Astronomers Find Comets Orbiting a Star 800 Light-Years Away

In the past thirty years, thousands of extra-solar planets have been discovered beyond our Solar System. For the most part, they have been detected by the Kepler Space Telescope using a technique called Transit Photometry. For this method, astronomers measure periodic dips in a star’s brightness – which are the result of planets passing in front of them relative to an observer – to confirm the presence of planets.

Thanks to a new research effort conducted by a team of professional and amateur astronomers, something much smaller than planets were recently detected orbiting a distant star. According to a new study published by the research team, six exocomets were observed orbiting around KIC 3542116, a spectral type F2V star located 800 light years from Earth. These comets are the smallest objects to date detecting the Transit Photometry method.

The study which details their findings, titled “Likely Transiting Exocomets Detected by Kepler“, recently appeared in the Monthly Notices of the Royal Astronomical Society. Led by Saul Rappaport of MIT’s Kavli Institute for Astrophysics and Space Research, the team also consisted of amateur astronomers, members of the Harvard-Smithsonian Center for Astrophysics (CfA), the University of Texas, Northeastern University, and NASA’s Ames Research Center.

Artist’s impression of an orbiting swarm of dusty comet fragments around Tabby’s Star. Credit: NASA/JPL-Caltech

This is the first time that Transit Photometry has been used to detect object as small as comets. These comets were balls of ice and dust – comparable in size to Halley’s Comet – that were found to be traveling at speeds of about 160,934 km/h (100,000 mph) before they vaporized. The researchers were able to detect them by picking out their tails, the clouds of dust and gas that form when comets get closer to their star and begin to sublimate.

This was no easy task, since the tails managed to obscure only about a tenth of 1% of the star’s light. As Saul Rappaport, who is also the professor emeritus of physics at the Kavli Institute for Astrophysics and Space Research, explained in an MIT press release:

“It’s amazing that something several orders of magnitude smaller than the Earth can be detected just by the fact that it’s emitting a lot of debris. It’s pretty impressive to be able to see something so small, so far away.”

Credit for the original detection goes to Thomas Jacobs, an amateur astronomer who lives in Bellevue, Washington, and is a member of Planet Hunters. This citizen scientist project was first established by Yale University and consists of amateur astronomers who dedicated their time to the search for exoplanets. Members are given access to data from the Kepler Space Telescope in the hopes that they would notice things that computer algorithms might miss.

NASA’s Kepler space telescope was the first agency mission capable of detecting Earth-size planets. Credit: NASA/Wendy Stenzel

Back in January, Jacobs began scanning four years of data obtained during Kepler‘s main mission. During this phase, which lasted from 2009 to 2013, Kepler scanned over 200,000 stars and conducted measurements of their light curves. After five months of sifting through the data (on March 18th), he noticed several curious light patterns amid background noise coming from KIC 3542116. As Jacobs said:

“Looking for objects of interest in the Kepler data requires patience, persistence, and perseverance. For me it is a form of treasure hunting, knowing that there is an interesting event waiting to be discovered. It is all about exploration and being on the hunt where few have traveled before.”

Specifically, Jacobs was searching for signs of single transits, which are not like those that are caused by planets orbiting a star (i.e. periodic). While looking at KIC 3542116, he noticed three single transits, and then alerted Rappaport and Andrew Vanderburg, as astrophysicist at University of Texas and member of the CfA. Jacobs had worked with both men in the past, and wanted their opinion on these findings.

As Rapport recalled, the process of interpreting the data was challenging, but rewarding. Initially, they noted that the lightcurves did not resemble those caused by planetary transits, which are characterized by a sudden and sharp drop in light, followed by a sharp rise. In time, Rapport noted the asymmetry in the three lightcurves resembled those of disintegrated planets, which they had observed before.

Artist’s impression of the Epsilon Eridani system, showing Epsilon Eridani b (a Jupiter-mass planet) and a series of asteroid belts and comets. Credit: NASA/SOFIA/Lynette Cook.

“We sat on this for a month, because we didn’t know what it was — planet transits don’t look like this,” said Rappaport. “Then it occurred to me that, ‘Hey, these look like something we’ve seen before’… We thought, the only kind of body that could do the same thing and not repeat is one that probably gets destroyed in the end. The only thing that fits the bill, and has a small enough mass to get destroyed, is a comet.”

Based on their calculations, which indicated that each comet blocked out about one-tenth of 1% of the star’s light, the research team concluded that the comet likely disintegrated entirely, creating a dust trail that was sufficient to block out light for several months before it disappeared. After conducting additional observations, they also noted three more transits in the same time period that were similar to the ones noticed by Jacobs.

The fact that these six exocomets appear to have transited very close to their star in the past four years raises some interesting questions, and answering them could have drastic implications for extra-solar research. It could also advance our understanding of our own Solar System. As Vanderburg explained:

“Why are there so many comets in the inner parts of these solar systems? Is this an extreme bombardment era in these systems? That was a really important part of our own solar system formation and may have brought water to Earth. Maybe studying exocomets and figuring out why they are found around this type of star… could give us some insight into how bombardment happens in other solar systems.”

This artist’s conception illustrates a storm of comets around a star near our own. Credit: NASA/JPL-Caltech

Between 4.1 and 3.8 billion years ago, the Solar System also experienced a period of intense comet activity known as the Late Heavy Bombardment. During this time, asteroids and comets are believed to have impacted bodies in the inner Solar System on a regular basis. Interestingly, this period of heavy bombardment is believed to be what was responsible for the distribution of water to Earth and the other terrestrial planets.

As noted, KIC 3542116 belongs to the spectral type F2V, a yellow-white class of star that is typically 1 to 1.4 times as massive as our Sun and quite bright. Since it is comparable in size and mass to our Sun, it is possible that the bombardment period it is experiencing is similar to what the Solar System went through. Watching it unfold could therefore tell us much about how similar activity influenced the evolution of our Solar System billions of years ago.

In addition to the study’s significance to the study of astrophysics and astronomy, it also demonstrates the important role citizen scientists play today. Were it not for the tireless work performed by Jacobs, who sifts through Kepler data between working his day job and on the weekends, this discovery would not have been possible.

“I could name 10 types of things these people have found in the Kepler data that algorithms could not find, because of the pattern-recognition capability in the human eye,” said Rappaport. “You could now write a computer algorithm to find this kind of comet shape. But they were missed in earlier searches. They were deep enough but didn’t have the right shape that was programmed into algorithms. I think it’s fair to say this would never have been found by any algorithm.”

In the future, the research team expects that the deployment Transiting Exoplanet Survey Satellite (TESS) – which will be led by MIT – will continue to conduct the type of research performed by Kepler.

Further Reading: MIT, MNRAS

Three Possible Super-Earths Discovered Around Nearby Sun-Like Star

Since it was launched in 2009, NASA’s Kepler mission has continued to make important exoplanet discoveries. Even after the failure of two reaction wheels, the space observatory has found new life in the form of its K2 mission. All told, this space observatory has detected 5,017 candidates and confirmed the existence of 2,494 exoplanets using the Transit Method during its past eight years in service.

The most recent discovery was made by an international team of astronomers around Gliese 9827 (GJ 9827), a late K-type dwarf star located about 100 light-years from Earth. Using data provided by the K2 mission, they detected the presence of three Super-Earths. This star system is the closest exoplanet-hosting star discovered by K2 to date, which makes these planets well-suited for follow-up studies.

The study which describes their findings, titled “A System of Three Super Earths Transiting the Late K-Dwarf GJ 9827 at Thirty Parsecs“, was recently published online. Led by Dr. Jospeh E. Rodriguez from the Harvard-Smithsonian Center for Astrophysics (CfA), the team includes researchers from the University of Austin, the Massachusetts Institute of Technology (MIT), and the NASA Exoplanet Science Institute (NExSci) at Caltech.

The Transit Method, which remains one of the most trusted means for exoplanet detection, consists of monitoring stars for periodic dips in brightness. These dips correspond to planets passing (aka. transiting) in front of the star causing a measurable drop in the light coming from it. This method also offers unique opportunities to examine light passing through an exoplanet’s atmosphere. As Dr. Rodriguez told Universe Today via email:

“The success of Kepler combined with ground based radial velocity and transit surveys has now led to the discovery of over 4000 planetary system. Since we now know that planets appear to be quite common, the field has shifted its focus to understand architectures, interior structures, and atmospheres. These key properties of planetary systems help us understand some fundamental questions: how do planets form and evolve? What are the terrestrial planets around other stars like, are they similar to Earth in composition and atmosphere?”

These questions were central to the team’s study, which relied on data obtained during Campaign 12 of the K2 mission – from December 2016 to March 2017. After consulting this data, the team noted the presence of three super-Earth sized planets orbiting in a very compact configuration. This system, as they note in their study, was independently and simultaneously discovered by another team from Wesleyan University.

These three planetary objects, designated as GJ 9827 b, c, and d, are located at a distance of about 0.02, 0.04 and 0.06 AU from their host star (respectively). Owing to their sizes and radii, these planets are classified as “Super-Earths”, and have radii of 1.6, 1.2, and 2.1 times the radius of Earth. They are also located very close to their host star, completing orbits within 6.2 days.

The light curve obtained during Campaign 12 of the K2 mission of the GJ 9827 system. Credit: Rodriguez et al., 2017

Specifically, GJ 9827 b measures 1.64 Earth radii, has a mass of up to 4.25 Earth masses, a 1.2 day orbital period, and a temperature of 1,119 K (846 °C; 1555 °F). Meanwhile, GJ 9827 c measures 1.29 Earth radii, has a mass of 2.62 Earth masses, an orbital period of 3.6 days, and a temperature of 774 K (500 °C; 934°F). Lastly, GJ 9827 d measures 2.08 Earth radii, has a mass of 5.3 Earth masses, a 6.2 day period, and a temperature of 648 K (375 °C; 707 °F).

In short, all three planets are very hot, with temperatures that are hot as Venus and Mercury or (in the case of GJ 9827b) is even hotter! Interestingly, these radii and mass estimates place these planets within the transition boundary between terrestrial (i.e. rocky) planets and gas giants. In fact, the team found that GJ 9827 b and c fall in or close to the known gap in radius distribution for planets that are in between these two populations.

In other words, these planets could be rocky or gaseous, and the team won’t know for sure until they can place more accurate constraints on their masses. What’s more, none of these planets are likely to be capable of supporting life, certainly not as we know it! So if you were hoping that this latest find would produce an Earth-analog or potentially habitable planet, you’re sadly mistaken.

Nevertheless, the fact that these planets straddle the radius and mass boundary between terrestrial and gaseous planets – and the fact that this system is the closest planetary system to be identified by the K2 mission – makes the system well-situated for studies designed to probe the interior structure and atmosphere of exoplanets.

Artistic design of the super-Earth orbiting a Sun-like star. Credit: Gabriel Pérez/SMM (IAC)

The reason for this has much to do with the brightness of the host star. In addition to being relatively close to our Sun (~100 light-years), this K-type star is very bright and also relatively small – about 60% the size of our Sun. As a result, any planet passing in front of it would be able to block out more light than if the star were larger. But as noted, there’s also the curious nature of the planets themselves. As Dr. Rodriguez indicated:

Recently, we have found planets around other stars that have no analogue to a planet in our own system. These are known as “super Earths” and they have radii of 1-3 times the radius of the Earth. To add to the complexity of these planets, their is a clear dichotomy in their composition within this radius range. The larger super Earths (>1.6 x radius of the Earth) appear to be less dense, consistent with a puffy Hydrogen/Helium atmosphere. However, the smaller super Earths are more dense, consistent with an Earth-like composition (rock).

“As mentioned above, the GJ 9827 system hosts three super Earth sized planets. Interestingly, planet c has a radius consistent with it being rocky, planet d is consistent with being puffy, and planet b has a radius that is right on what we believe to be the transition boundary between rock and gas. Therefore, by studying the atmospheres of super-Earths, we may better understand the transition from dense rocky planets to puffier planets with very thick atmospheres (like Neptune).”

Artist’s impression of the super-Earth orbiting closely to its parent star. Credit: ESA/NASA

Looking ahead, the team hopes to conduct further studies to determine the masses of these planets more precisely. From this, they will be able to place better constraints on their compositions and determine if they are Super-Earths, mini gas giants, or some of each. Beyond that, they are to conduct more detailed studies of this system with next-generation instruments like the James Webb Space Telescope (JWST), which is scheduled to launch in 2018.

“I am really interested in studying the atmosphere of GJ 9827 b, whether it is rocky or puffy,” said Dr. Rodriguez. “This planet has a radius at the rock/gas transition but it is very close to its host star. Therefore, by studying the chemical composition of its atmosphere we may better understand the impact of the host star’s proximity has on the evolution of its atmosphere.  To do this we would use JWST to take spectroscopic observations during the transit of GJ 9827b (known as “Transmission Spectroscopy”). From this observations we will gather information on the chemical composition and extent of the planet’s atmosphere.

Now that we have thousands of extra-solar planet discoveries under our belt, its only natural that research would be shifting towards trying to understand these planets better. In the coming years and decades, we are likely to learn volumes about the respective structures, compositions, atmospheres, and surface features of many distant worlds. One can only imagine what kind of things these studies will turn up!

Further Reading: arXiv

Exoplanet-Hunting Aliens Could Be Looking at Earth Right Now!

In the past few decades, the search for extra-solar planets has turned up a wealth of discoveries. Between the many direct and indirect methods used by exoplanet-hunters, thousands of gas giants, rocky planets and other bodies have been found orbiting distant stars. Aside from learning more about the Universe we inhabit, one of the main driving forces behind these efforts has been the desire to find evidence of Extra-Terrestrial Intelligence (ETI).

But suppose there are ETIs out there that are are also looking for signs of intelligence other than their own? How likely would they be to spot Earth? According to a new study by a team of astrophysicists from Queen’s University Belfast and the Max Planck Institute for Solar System Research in Germany, Earth would be detectable (using existing technology) from several star systems in our galaxy.

This study, titled “Transit Visibility Zones of the Solar System Planet“, was recently published in the Monthly Notices of the Royal Astronomical Society. Led by Robert Wells, a PhD student at the Astrophysics Research Center at Queen’s University Belfast, the team considered whether or not Earth would be detectable from other star systems using the Transit Method.

Diagram of a planet (e.g. the Earth, blue) transiting in front of its host star (e.g. the Sun, yellow). The lower black curve shows the brightness of the star noticeably dimming over the transit event, when the planet is blocking some of the light from the star. Credit: R. Wells.

This method consists of astronomers observing stars for periodic dips in brightness, which are attributed to planets passing (i.e. transiting) between them and the observer. For the sake of their study, Wells and his colleagues reversed the concept in order to determine if Earth would be visible to any species conducting observations from vantage points beyond our Solar System.

To answer this question, the team looked for parts of the sky from which one planet would be visible crossing the face of the Sun – aka. “transit zones”. Interestingly enough, they determined that the terrestrial planets that are closer to the Sun (Mercury, Venus, Earth and Mars) would easier to detect than the gas and ice giants – i.e.  Jupiter, Saturn, Uranus and Neptune.

While considerably larger, the gas/ice giants would be more difficult to detect using the transit method because of their long-period orbits. From Jupiter to Neptune, these planets take about 12 to 165 years to complete a single orbit! But more important than that is the fact that they orbit the Sun at much greater distances than the terrestrial planets. As Robert Wells indicated in a Royal Astronomical Society press statement:

”Larger planets would naturally block out more light as they pass in front of their star. However the more important factor is actually how close the planet is to its parent star – since the terrestrial planets are much closer to the Sun than the gas giants, they’ll be more likely to be seen in transit.”

How the transit zone of a Solar System planet is projected out from the Sun. The observer on the green exoplanet is situated in the transit zone and can therefore see transits of the Earth. Credit: R. Wells

Ultimately, what the team found was that at most, three planets could be observed from anywhere outside of the Solar System, and that not all combinations of these three planets was possible. For the most part, an observer would see only planet making a transit, and it would most likely be a rocky one. As Katja Poppenhaeger, a lecturer at the School of Mathematics and Physics at Queen’s University Belfast and a co-author of the study, explained:

“We estimate that a randomly positioned observer would have roughly a 1 in 40 chance of observing at least one planet. The probability of detecting at least two planets would be about ten times lower, and to detect three would be a further ten times smaller than this.”

What’s more, the team identified sixty-eight worlds where observers would be able to see one or more of the Solar planets making transits in front of the Sun. Nine of these planets are ideally situated to observe transits of the Earth, though none of them have been deemed to be habitable. These planets include HATS-11 b, 1RXS 1609 b, LKCA 15 b, WASP-68 b, WD 1145+017 b, and four planets in the WASP-47 system (b, c, d, e).

On top of that, they estimated (based on statistical analysis) that there could be as many as ten undiscovered and potentially habitable worlds in our galaxy which would be favorably located to detect Earth using our current level of technology. This last part is encouraging since, to date, not a single potentially habitable planet has been discovered where Earth could be seen making transits in front of the Sun.

Image showing where transits of our Solar System planets can be observed. Each line represents where one of the planets could be seen to transit, with the blue line representing Earth; an observer located here could detect us. Credit: 2MASS/A. Mellinger/R. Wells.

The team also indicated that further discoveries made by the Kepler and K2 missions will reveal additional exoplanets that have “a favorable geometric perspective to allow transit detections in the Solar System”. In the future, Wells and his team plan to study these transit zones to search for exoplanets, which will hopefully reveal some that could also be habitable.

One of the defining characteristics in the Search for Extra-Terrestrial Intelligence (SETI) has been the act of guessing about what we don’t know based on what we do. In this respect, scientists are forced to consider what extra-terrestrial civilizations would be capable of based on what humans are currently capable of. This is similar to how our search for potentially habitable planets is limited since we know of only one where life exists (i.e. Earth).

While it might seem a bit anthropocentric, it’s actually in keeping with our current frame of reference. Assuming that intelligent species could be looking at Earth using the same methods we do is like looking for planets that orbit within their star’s habitable zones, have atmospheres and liquid water on the surfaces.

In other words, it’s the “low-hanging fruit” approach. But thanks to ongoing studies and new discoveries, our reach is slowly extending further!

Further Reading: RAS, MNRAS

Advanced Civilizations Could Build a Galactic Internet with Planetary Transits

In a series of papers, Professor Loeb and Michael Hippke indicate that conventional rockets would have a hard time escaping from certain kinds of extra-solar planets. Credit: NASA/Tim Pyle

Decades after Enrico Fermi’s uttered his famous words – “Where is everybody?” – the Paradox that bears his name still haunts us. Despite repeated attempts to locate radio signals coming from space and our ongoing efforts to find visible indications of alien civilizations in distant star systems, the search extra-terrestrial intelligence (SETI) has yet to produce anything substantive.

But as history has taught us, failure has a way of stimulated new and interesting ideas. For example, in a recently-published paper, Dr. Duncan H. Forgan of St. Andrews University proposed that extra-terrestrial civilizations could be communicating with each other by creating artificial transits of their respective stars. This sort of “galactic internet” could be how advanced species are attempting to signal us right now.

Forgan’s paper, “Exoplanet Transits as the Foundation of an Interstellar Communications Network“, was recently published online. In addition to being a research fellow at the School of Physics and Astronomy and the Scottish Universities Physics Alliance at the University of St Andrews (Scotland’s oldest academic institution), he is also a member of the St Andrews Center for Exoplanet Science.

The paper begins by addressing the two fundamental problems associated with interstellar communication – timing and energy consumption. When it comes to things like radio transmissions, the amount of energy that would be needed to transmit a coherent message over interstellar distances is prohibitive. Optical communications (i.e. lasers) need less energy, but spotting them would require incredibly precise timing.

As such, neither method would be particularly reliable for establishing an interstellar communications system. Taking a cue from humanity’s recent exoplanet-hunting efforts, Forgan argues that a method where transits in front of a stars are a basis of communication would solve both problems. The reason for this is largely due to the fact that the Transit Method is currently one of the most popular and reliable ways of detecting exoplanets.

By monitoring a star for periodic dips in brightness, which are caused by a planet or object passing between the observer and the star, astronomers are able to determine if the star has a system of planets. The method is also useful for determining the presence and composition of atmospheres around exoplanet. As Forgan indicates in the paper, this method could therefore be used as a means of signalling other civilizations:

“An ETI ’A’ can communicate with ETI ’B’ if B is observing transiting planets in A’s star system, either by building structures to produce artificial transits observable by B, or by emitting signals at B during transit, at significantly lower energy consumption than typical electromagnetic transmission schemes.”
The Milky Way’s habitable zone. Credit: NASA/Caltech

In short, Forgan argued that within the Galactic Habitable Zone (GHZ) – the region of the Milky Way in which life is most likely develop – species may find that the best way to communicate with each other is by creating artificial megastructures to transit their star. These transits, which other civilizations will be looking for (looking for exoplanets, like us!) will lead them to conclude that an advanced civilization exists in another star system.

He even offers estimates on how often such transmissions could be made. As he put it:

“A message with a path of 20 kpc (the diameter of the GHZ) has a total travel time at lightspeed of just under 0.06 Myr. If we assume a relatively short timescale on which both ETIs remain in the transit zone of 100,000 years (which is approaching the timescale on which both secular evolution of planetary orbits and the star’s orbit become important), then a total of 30 exchanges can be made. This of course does not forbid a continuing conversation by other means.”

If this is starting to sound familiar, that’s probably because this is precisely what some theorists say is happening around KIC 8462852 (aka. Tabby’s Star). Back in May of 2015, astronomers noticed that the star had been undergoing considerable drops in brightness in the past few years. This behavior confounded natural explanations, which led some to argue that it could be the result of an alien megastructure passing in front of the star.

According to Forgan, such a possibility is hardly far-fetched, and would actually be a relatively economical means of communicating with other advanced species. Using graph theory, he estimated that civilizations within the GHZ could establish a fully connected network within a million years, where all civilizations are in communication with each other (either directly or via intermediate civilizations).

Artist’s concept of KIC 8462852, which has experienced unusual changes in luminosity over the past few years. Credit: NASA, JPL-Caltech

Not only would this network require far less energy to transmit data, but the range of any signal would be limited only by the extent of these civilizations themselves. Beyond saving energy and having greater range (assuming intermediate civilizations are able to pass messages along), this method presents other advantages. For one, a high level of technological sophistication would be required to pick up the transit of exoplanets.

In other words, civilizations would need to reach a certain level of development before they could hope to join the network. This would prevent any unfortunate “cultural contamination”, where less-advanced civilizations learned about the existence of aliens before they were ready. Second, once acquired, the transit network signals would be extremely predictable, with each transmission corresponding to a known orbital period.

That being said, there are some downsides that Forgan was sure to acknowledge. For starters, the periodicity of these signals would be a double edged sword, as signals could only be sent if and when the receiver begins to see the transit. And while a megastructure could be moved to alter the transit period, this poses problems in terms of synchronizing transmission and reception.

Addressing the limitations of the analysis, Forgan also acknowledges that the study relies on fixed stellar orbits. The orbits of stars are known to change over time, with stars passing in and out of the GHZ regularly on cosmic timescales. In addition, there is also the issue of how such a network would differ between denser regions in the galaxy – i.e. globular clusters – and areas populated by field stars. Binary stars are also not considered in the analysis.

Could alien megastructures be the key to interstellar communications? Credit: Kevin Gill

In addition, planetary orbits are known to change over time, due to perturbations caused by neighboring planets, companion stars, or close encounters with passing stars. As a result, the visibility of transiting planets can vary even more over cosmic timescales. Last, but not least, the study assumes that civilizations have a natural lifespan of about a billion years, which is not based in any concrete knowledge.

However, these considerations do not alter the overall conclusions reached by Forgan. Making allowances for the dynamic nature of stars and planets, and assuming that civilizations exist for only 1 million years, Forgan maintains that the creation of an interstellar network of this kind is still mathematically feasible. On top of that, an artificial object could continue to signal other species long after a civilization has gone extinct.

Addressing the Fermi Paradox, Forgan concludes that this sort of communication would take a long time to detect.As he summarizes in the paper (bold added for emphasis):

“I find that at any instant, only a few civilizations are correctly aligned to communicate via transits. However, we should expect the true network to be cumulative, where a “handshake” connection at any time guarantees connection in the future via e.g. electromagnetic signals. In all our simulations, the cumulative network connects all civilizations together in a complete network. If civilizations share knowledge of their network connections, the network can be fully complete on timescales of order a hundred thousand years. Once established, this network can connect any two civilizations either directly, or via intermediate civilizations, with a path much less than the dimensions of the GHZ.”

In short, the reason we haven’t heard from or found evidence of ETI could be an issue of timing. Or, it could be that we simply didn’t realize we were being communicated with. While such an analysis is subject to guess-work and perhaps a few anthropocentric assumptions, it is certainly fascinating because of the possibilities it presents. It also offers us a potential tool in the search for extra-terrestrial intelligence (SETI), one which we are already engaged in.

So many stars, so many planets. So many opportunities for connection! Credit: ESO/M. Kornmesser

And last, but not least, it offers a potential resolution to the Fermi Paradox, one which we may have already stumbled upon and are simply not yet aware of. For all we know, the observed drops in brightness coming from Tabby’s Star are evidence of an alien civilization (possibly an extinct one). Of course, the key word here is “perhaps”, as no evidence exists that could confirm this.

The possibilities raised by this paper are also exciting given that exoplanet-hunting is expected to ramp up in the coming years. With the deployment of next-generations missions like the James Webb Space Telescope and the Transiting Exoplanet Survey Satellite (TESS), we expect to be learning a great deal more about star systems both near and far.

Will we find more examples of unexplained drops in brightness? Who knows? The point is, if we do (and can’t find a natural cause for them) we have a possible explanation. Maybe its neighbors inviting us to “log on”!

Further Reading: arXiv

Finally! A Low Mass Super-Earth With Some Funky Atmosphere

In 2015, astronomers discovered an intriguing extrasolar planet located in a star system some 39 light years from Earth. Despite orbiting very close to its parent star, this “Venus-like” planet – known as GJ 1138b – appeared to still be cool enough to have an atmosphere. In short order, a debate ensued as to what kind of atmosphere it might have, whether it was a “dry Venus” or a “wet Venus”.

And now, thanks to the efforts of an international team of researchers, the existence of an atmosphere has been confirmed around GJ 1138b. In addition to settling the debate about the nature of this planet, it also marks the first time that an atmosphere has been detected around a low-mass Super-Earth. On top of that, GJ 1138b is now the farthest Earth-like planet that is known to have an atmosphere.

Led by John Southworth (of Keele University) and Luigi Mancini (of the University of Rome Tor Vergata), the research team included members from the Max Planck Institute for Astronomy (MPIA), the National Institute for Astrophysics (INAF), the University of Cambridge and Stockholm University. Their study, titled “Detection of the atmosphere of the 1.6 Earth mass exoplanet GJ 1132b“, recently appeared in The Astrophysical Journal.

Artist’s impression of the “Venus-like” exoplanet GJ 1132b. Credit: cfa.harvard.edu

Using the GROND imager on the La Silla Observatory’s 2.2m ESO/MPG telescope, the team monitored GJ 1132b in different wavelengths as it transited in front of its parent star. Given the planet’s orbital period (1.6 days), these transits happen quite often, which presented plenty of opportunities to view it pass in front of its star. In so doing, they monitored the star for slight decreases in its brightness.

As Dr. Southworth explained to Universe via email, these observations confirmed the existence of an atmosphere:

“What we did was to measure the amount of dimming at 7 different wavelengths in optical and near-infrared light. At one of these wavelengths (IR) the planet seemed to be slightly bigger. This indicated that the planet has a large atmosphere around it which allows most of the starlight to pass through, but is opaque at one wavelength.”

The team members from the University of Cambridge and the MPIA then conducted simulations to see what this atmosphere’s composition could be. Ultimately, they concluded that it most likely has a thick atmosphere that is rich in water and/or methane – which contradicted recent theories that the planet had a thin and tenuous atmosphere (i.e. a “dry Venus”).

The ESO’s Paranal Observatory, located in the Atacama Desert of Chile. Credit: ESO

It was also the first time that an atmosphere has been confirmed around a planet that is not significantly greater in size and mass to Earth. In the past, astronomers have detected atmospheres around many other exoplanets. But in these cases, the planets were either gas giants or planets that were many times Earth’s size and mass (aka. “Super-Earths”). GJ 1132b, however, is 1.6 times as massive as Earth, and measures 1.4 Earth radii.

In addition, these findings are a significant step in the search for life beyond our Solar System. At present, astronomers seek to determine the chemical composition of a planet’s atmosphere to determine if it could be habitable. Where the right combination of chemical imbalances exist, the presence of living organisms is seen as a possible cause.

By being able to determine that a planet at lower end of the super-Earth scale has an atmosphere, we are one step closer to being able to determine exoplanet habitability. The detection of an atmosphere-bearing planet around an M-type (red dwarf) star is also good news in and of itself. Low-mass red dwarf stars are the most common star in the galaxy, and recent findings have indicated that they might be our best shot for finding habitable worlds.

Besides detecting several terrestrial planets around red dwarf stars in recent years – including seven around a single star (TRAPPIST-1) – there is also research that suggests that these stars are capable of hosting large numbers of planets. At the same time, there have been concerns about whether red dwarfs are too variable and unstable to support habitable worlds.

Artist’s impression of Kepler-1649b, the “Venus-like” world orbiting an M-class star 219 light-years from Earth. Credit: Danielle Futselaar

As Southworth explained, spotting an atmosphere around a planet that closely orbits a red dwarf could help bolster the case for red dwarf habitability:

“One of the big issues has been that very-low-mass stars typically have strong magnetic fields and thus throw out a lot of X-ray and ultraviolet light. These high-energy photons tend to destroy molecules in atmospheres, and might also evaporate them completely. The fact that we have detected an atmosphere around GJ 1132b means that this kind of planet is indeed capable of retaining an atmosphere for billions of years, even whilst being bombarded by the high-energy photons from their host stars.

In the future, GJ 1132b is expected to be a high-priority target for study with the Hubble Space Telescope, the Very Large Telescope (VLT) at the Paranal Observatory in Chile, and next-generation telescopes like the James Webb Space Telescope (scheduled for launch in 2018). Already, observations are being made, and the results are being eagerly anticipated.

I’m sure I’m not the only one who would like to hear what astronomers discover as they set their sights on this nearby star system and it’s Venus-like world! In the meantime, be sure to check out this video about GJ 1132b, courtesy of MIT news:

Further Reading: Max Planck Institute for Astronomy

Who Else Is Looking For Cool Worlds Around Proxima Centauri?

Finding exoplanets is hard work. In addition to requiring seriously sophisticated instruments, it also takes teams of committed scientists; people willing to pour over volumes of data to find the evidence of distant worlds. Professor Kipping, an astronomer based at the Harvard-Smithsonian Center for Astrophysics, is one such person.

Within the astronomical community, Kipping is best known for his work with exomoons. But his research also extends to the study and characterization of exoplanets, which he pursues with his colleagues at the Cool Worlds Laboratory at Columbia University. And what has interested him most in recent years is finding exoplanets around our Sun’s closest neighbor – Proxima Centauri.

Kipping describes himself as a “modeler”, combining novel theoretical modeling with modern statistical data analysis techniques applied to observations. He is also the Principal Investigator (PI) of The Hunt for Exomoons with Kepler (HEK) project and a fellow at the Harvard College Observatory. For the past few years, he and his team have been taking the hunt for exoplanets to the local stellar neighborhood.

The inspiration for this search goes back to 2012, when Kipping was at a conference and heard the news about a series of exoplanets being discovery around Kepler 42 (aka. KOI-961). Using data from the Kepler mission, a team from the California Institute of Technology discovered three exoplanets orbiting this red dwarf star, which is located about 126 light years from Earth.

At the time, Kipping recalled how the author of the study – Professor Philip Steven Muirhead, now an associate professor at the Institute for Astrophysical Research at Boston University – commented that this star system looked a lot like our nearest red dwarf stars – Barnard’s Star and Proxima Centauri.

In addition, Kepler 42’s planets were easy to spot, given that their proximity to the star meant that they completed an orbital period in about a day. Since they pass regularly in front of their star, the odds of catching sight of them using the Transit Method were good.

As Prof. Kipping told Universe Today via email, this was the “ah-ha moment” that would inspire him to look at Proxima Centauri to see if it too had a system of planets:

“We were inspired by the discovery of planets transiting KOI-961 by Phil Muirhead and his team using the Kepler data. The star is very similar to Proxima, a late M-dwarf harboring three sub-Earth sized planets very close to the star. It made me realize that if that system was around Proxima, the transit probability would be 10% and the star’s small size would lead to quite detectable signals.”

The MOST satellite, a Canadian built space telescope. Credit: Canadian Space Agency
The MOST satellite, a Canadian built space telescope. Credit: Canadian Space Agency

In essence, Kipping realized that if such a planetary system also existed around Proxima Centauri, a star with similar characteristics, then they would very easy to detect. After that, he and his team began attempting to book time with a space telescope. And by 2014-15, they had been given permission to use the Canadian Space Agency’s Microvariability and Oscillation of Stars (MOST) satellite.

Roughly the same size as a suitcase, the MOST satellite weighs only 54 kg and is equipped with an ultra-high definition telescope that measures just 15 cm in diameter. It is the first Canadian scientific satellite to be placed in orbit in 33 years, and was the first space telescope to be entirely designed and built in Canada.

Despite its size, MOST is ten times more sensitive than the Hubble Space Telescope. In addition, Kipping and his team knew that a mission to look for transiting exoplanets around Proxima Centauri would be too high-risk for something like Hubble. In fact, the CSA initially rejected their applications for this same reason.

“MOST initially denied us because they wanted to look at Alpha Centauri following the announcement by Dumusque et al. of a planet there,” said Kipping. “So understandably Proxima, for which no planets were known at the time, was not as high priority as Alpha Cen. We never even tried for Hubble time, it would be a huge ask to stare HST at a single star for months on end with just a a 10% chance for success.”

Artist's impression of the Earth-like exoplanet discovered orbiting Alpha Centauri B iby the European Southern Observatory on October 17, 2012. Credit: ESO
Artist’s impression of the Earth-like exoplanet discovered orbiting Alpha Centauri B iby the European Southern Observatory on October 17, 2012. Credit: ESO

By 2014 and 2015, they secured permission to use MOST and observed Proxima Centauri twice – in May of both years. From this, they acquired a month and half’s-worth of space-based photometry, which they are currently processing to look for transits. As Kipping explained, this was rather challenging, since Proxima Centauri is a very active star – subject to star flares.

“The star flares very frequently and prominently in our data,” he said. “Correcting for this effect has been one the major obstacles in our analysis. On the plus side, the rotational activity is fairly subdued. The other issue we have is that MOST orbits the Earth once every 100 minutes, so we get data gaps every time MOST goes behind the Earth.”

Their efforts to find exoplanets around Proxima Centauri are especially significant in light of the European Southern Observatory’s recent announcement about the discovery of a terrestrial exoplanet within Proxima Centauri’s habitable zone (Proxima b). But compared to the ESO’s Pale Red Dot project, Kipping and his team were relying on different methods.

As Kipping explained, this came down to the difference between the Transit Method and the Radial Velocity Method:

“Essentially, we seek planets which have the right alignment to transit (or eclipse) across the face of the star, whereas radial velocities look for the wobbling motion of a star in response to the gravitational influence of an orbiting planet. Transits are always less likely to succeed for a given star, because we require the alignment to be just right. However, the payoff is that we can learn way more about the planet, including things like it’s size, density, atmosphere and presence of moons and rings.”

Artist’s impression of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Credit: ESO/M. Kornmesser
Artist’s impression of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. Credit: ESO/M. Kornmesser

In the coming months and years, Kipping and his team may be called upon to follow up on the success of the ESO’s discovery. Having detected Proxima b using the Radial Velocity method, it now lies to astronomers to confirm the existence of this planet using another detection method.

In addition, much can be learned about a planet through the Transit Method, which would be helpful considering all the things we still don’t know about Proxima b. This includes information about its atmosphere, which the Transit Method is often able to reveal through spectroscopic measurements.

Suffice it to say, Kipping and his colleagues are quite excited by the announcement of Proxima b. As he put it:

“This is perhaps the most important exoplanet discovery in the last decade. It would be bitterly disappointing if Proxima b does not transit though, a planet which is paradoxically so close yet so far in terms of our ability to learn more about it. For us, transits would not just be the icing on the cake, serving merely as a confirmation signal – rather, transits open the door to learning the intimate secrets of Proxima, changing Proxima b from a single, anonymous data point to a rich world where each month we would hear about new discoveries of her nature and character.”

This coming September, Kipping will be joining the faculty at Columbia University, where he will continue in his hunt for exoplanets. One can only hope that those he and his colleagues find are also within reach!

Further Reading: Cool Worlds

A Planet With A 27,000 Year Orbit & That’s Just Where The Strangeness Begins

Every planet in the Solar System has its own peculiar orbit, and these vary considerably. Whereas planet Earth takes 365.25 days to complete a single orbit about our Sun, Mars takes almost twice as long – 686.971 days. Then you have Jupiter and the other gas giants, which take between 11.86 and 164.8 years to orbit our Sun. But even with these serving as examples, astronomers were not prepared for what they found when they looked at CVSO 30.

This star system, which lies some 1200 light years from Earth, has been found in recent years to have two candidate exoplanets. These planets, which are many times the mass of Jupiter, were discovered by an international team of astronomers using both the Transit Method and Direct Imaging. And what they found was very interesting: one planet has an orbital period of less than 11 days while the other takes a whopping 27,000 years to orbit its parent star!

In addition to being a big surprise, the detection of these two planets using different methods was an historic achievement. Up until now, the vast majority of the over 2,000 exoplanets discovered have been detected thanks to indirect methods. These include the aforementioned Transit Method, which detects planets by measuring the dimming effect they cause when crossing their parent star’s path, and the Radial Velocity Method, which measures the gravitational effect planets have on their parent star.

In 2012, astronomers used the Transit Method to detect CVSO 30b, a planet with 5 to 6 times the mass of Jupiter, and which orbits its star at a distance of only 1.2 million kilometers (by comparison, Mercury orbits our Sun at a distance of 58 million kilometers). From these characteristics, CVSO 30b can be described as a particularly “hot-Jupiter”.

In contrast, Direct Imaging has been used to spot only a few dozen exoplanets. The reason for this is because it is typically quite difficult to detect the light reflected by a planet’s atmosphere due it being drowned out by the light of its parent star. It can also be quite demanding when it comes to the instrument involved. Still, compared to indirect methods, it can be more effective when it comes to exploring the remote regions of a star.

Thanks to the efforts of an international team of astronomers, who combined the use of the Keck Observatory in Hawaii, the ESO’s Very Large Telescope in Chile, and the Spanish National Research Council’s (CSIC) Calar Alto Observatory, CVSO 30c was spotted in remote regions around its parent star, orbiting at a distance of around 666 AU.

The details of the discovery were published in a paper titled “Direct Imaging discovery of a second planet candidate around the possibly transiting planet host CVSO 30“. In it, the researchers – who hail from such prestigious institutions as the Cerro Tololo Inter-American Observatory, the Jena Observatory, the European Space Agency and the Max Planck Institute for Astronomy – explained the methods used to find the exoplanet, and the significance of its discovery.

The star CVSO30, showing the two detection methods that revealed its exoplanet candidates. Credit: Keck Observatory/ESO/VLT/NACO
The star CVSO30, showing the two detection methods that revealed its exoplanet candidates. Credit: Keck Observatory/ESO/VLT/NACO

As Tobias Schmidt – of the University of Hamburg, the Astrophysical Institute and University Observatory Jena, and the lead author of the paper – told Universe Today via email:

“[30b and 30c] are both unusual on their own. CVSO 30b is the first transiting planet around a star as young as 2.5 million years. Published in 2012, all previously detected transiting planets were older than few hundred million years… It has been a surprise to find a planetary mass companion at 662 AU, or 662 times the distance from Earth to the Sun, from a primary star having only about 0.4 solar masses. According to the standard model, planets form in disks around the star. But none of the observed disks around such low-mass stars is large enough to form such an object.”

In other words, it is surprising to find two exoplanet candidates with several times the mass of Jupiter (aka. Super-Jupiters) orbiting a star as small as CVSO 30. But to find two exoplanets with such a disparity in terms of their respective distance from their star (despite being similar in mass) was particularly surprising.

Relying on high-contrast photometric and spectroscopic observations from the Very Large Telescope, the Keck telescopes and the Calar Alto observatory, the international team was able to spot 30c using a technique known as lucky imaging. This process, which is used by ground-based telescopes, involves many high-speed, quick exposure photos being taken to minimize atmospheric interference.

An artist's conception of a T-type brown dwarf. (Credit: Tyrogthekreeper under a Wikimedia Commons Attribution-Share Alike 3.0 Unported license).
An artist’s conception of a T-type brown dwarf. Credit: Tyrogthekreeper/Wikimedia Commons.

What they found was an exoplanet with a wide orbit that was between 4 and 5 Jupiter masses, and was also very young – less than 10 million years old. What’s more, the spectroscopic data indicated that it is unusually blue for a planet, as most other planet candidates of its kind are very red. The researchers concluded from this that it is likely that 30c is the first young planet of its kind to be directly imaged.

They further concluded that 30 c is also likely the first “L-T transition object” younger than 10 million years to be found orbiting a star. L-T transition objects are a type of brown dwarf – objects that are too large to be considered planets, but too small to be considered stars. Typically they are found embedded in large clouds of gas and dust, or on their own in space.

Paired with its companion – 30 b, which is impossibly close to its parent star – 30 c is not believed to have formed at its current position, and is likely not stable in the long-term. At least, not where current models of planetary formation and orbit are concerned. However, as Prof. Schmidt indicated, this offers a potential explanation for the odd nature of these exoplanets.

“We do think this is a very good hint,” he said, “that the two objects might have formed regularly around the star at a separation comparable to Jupiter or Saturn’s separation from the Sun, then interacted gravitationally and were scattered to their current orbits. However this is still speculation, further investigations will try to prove this. Both have about the same mass of few Jupiter masses, the inner one might be even lower.”

The Very Large Telescoping Interferometer firing it's adaptive optics laser. Credit: ESO/G. Hüdepohl
The Very Large Telescoping Interferometer firing it’s adaptive optics laser. Credit: ESO/G. Hüdepohl

The discovery is also significant since it was the first time that these two detection methods – Transit and Direct Imaging – were used to confirm exoplanet candidates around the same star. In this case, the methods were quite complimentary, and present opportunities to learn more about exoplanets. As Professor Schmidt explained:

“Both Transit method and radial velocity method have problems finding planets around young stars, as the activity of young stars is disturbing the search for them. CVSO 30 b was the first very young planet found with these methods, currently a hand full of candidates exist. Direct imaging, on the other hand, is working best for young planets as they still contract and are thus self-luminous. It is therefore great luck that a far out planet was found around the very first young star hosting a inner planet…

“However, the real advantage of transit and direct imaging methods is that the two objects can now be investigated in greater detail. While we can use the direct light from the imaging for spectroscopy, i.e. split the light according to its wavelength, we hope to achieve the same for the inner planet candidate. This is possible as the light passes through the atmosphere of the planet during transits and some of the elements are absorbed by the composition material of the atmosphere. So we do hope to learn a lot about planet formation, thus also formation of the early Solar System and about young planets in particular from the CVSO 30 system.”

Since astronomers first began began to find exoplanet candidates in distant star systems, we have come to learn just how diverse our Universe really is. Many of the discoveries have challenged our notions about where planets can form around their parent star, while others have showed us that planets can take many different forms.

As time goes on and our exploration of the local Universe advances, we will be challenged to find explanations for how it all fits together. And from that, new and more comprehensive models will no doubt emerge.

Further Reading: IAA, arXiv

Starshade Prepares To Image New Earths

Artist's concept of the prototype starshade, a giant structure designed to block the glare of stars so that future space telescopes can take pictures of planets. Credit: NASA/JPL

For countless generations, people have looked up at the stars and wondered if life exists somewhere out there, perhaps on planets much like ours. But it has only been in recent decades that we have been able to confirm the existence of extrasolar planets (aka. exoplanets) in other star systems. In fact, between 1988 and April 20th of 2016, astronomers have been able to account for the existence of 2108 planets in 1350 different star systems, including 511 multiple planetary systems.

Most of these discoveries have taken place within just the past three years, thanks to improvements in our detection methods, and the deployment of the Kepler space observatory in 2009. Looking ahead, astronomers hope to improve on these methods even further with the introduction of the Starshade, a giant space structure designed to block the glare of stars, thus making it easier to find planets – and perhaps another Earth!

Continue reading “Starshade Prepares To Image New Earths”

Russia Will Begin Hunt For Extrasolar Planets

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Located just south of Saint Petersburg on Pulkovo Heights, one of the greatest Russian Observatories of all times – the Pulkovo Observatory – is about to embark on a very noble study. According to the head of the Institute for Space Research, Lev Zelyony, the Soviet telescopes are about to turn their eyes towards deep skies in search of extrasolar planets. “Scientists from the Pulkovo Observatory are planning to use ground-based instruments to study the transit of planets around their parent stars,” Zelyony said at a roundtable meeting at RIA Novosti headquarters in Moscow.

The observatory was absolutely state-of-the-art when it opened for business in 1839 and employed Wilhelm von Struve as its director. It houses some of the largest refractor telescopes in the world, including a 38-cm (15 in.) aperture refractor and a 30-inch (76 cm) refractor – both built by Alvan Clarke and Sons. Fifty years later, they added an astrophysical laboratory, a mechanical workshop and installed one of Europe’s largest lensed telescope, a 76-cm refractor (30 inch). Later additions to the observatory included a Littrow spectrograph and horizontal solar telescope and the facility blossomed into a world leader in stellar spectroscopy, cataloging and more. Modern improvements include astrograph equipment, an interferometer, radio telescope and even an additional 65-cm (26-inch) refractor. The Pulkovo Observatory is up to the task.

Pulkovo Observatory 2004 - Credit: Vladimir Ivanov

The hunt for exoplanets is one of the most popular aspects of modern astronomy and one of the fastest growing fields. In less than 25 years, 755 and an ever-increasing number of planets have been cataloged… and the research just doesn’t end. The United States Kepler Mission and French CoRoT space telescope have had their share of fun, but using a ground-based telescope could also be a viable source of planet detection, Zelyony said. He also cited the example of the Hungarian Automated Telescope Network (HATNet) which so far has discovered 29 exoplanets. By using the transit detection method, the Russian astronomers are eager to begin observations where a small change in magnitude could mean a big change in the way their telescopes perceive the stars.

“It is an interesting research, which should be pursued,” Zelyony said. “It will also help us look at our Solar System from a different perspective.”

Original Story Source: Rionovosti News Release.

11 New Planetary Systems… 26 New Planets… Kepler Racks ‘Em Up!

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Eleven ball in the side pocket. Whack! And another 26 planets are discovered! NASA just announced the latest tally and the new discoveries come close to doubling the amount of verified planets and tripling the number of stars which are confirmed to have more than one transiting planet. It’s just another score for understanding how planets came to be… planets which run the gambit from about one and half times the size of Earth up to the size of Jupiter. Of these, fifteen are judged to be between the size of Earth and Neptune – while more observations will reveal their structure. The new bodies orbit the parent star between 6 and 143 days and all are closer than our Sun/Venus distance.

“Prior to the Kepler mission, we knew of perhaps 500 exoplanets across the whole sky,” said Doug Hudgins, Kepler program scientist at NASA Headquarters in Washington. “Now, in just two years staring at a patch of sky not much bigger than your fist, Kepler has discovered more than 60 planets and more than 2,300 planet candidates. This tells us that our galaxy is positively loaded with planets of all sizes and orbits.”

Kepler is a busy-body. It monitors the brightness changes in more than 150,000 stars. Through repeated measurements, it is able to pick out minute magnitude fluctuations which occur as a planet passes between us, Kepler and the parent sun. The newly documented solar systems are host to between two and five closely situated transiting bodies. In such cramped systems, the gravitational interaction between the orbiting members means some are accelerated – and others decelerated – in their tracks. Faster orbital speeds account for changes in orbital periods… Changes that the Kepler mission documents as Transit Timing Variations (TTVs). For planetary systems possessing TTVs, no extreme study with ground-based telescopes is required to verify their existence and the technique allows Kepler to validate the presence of planetary systems around further and fainter stars.

What’s been found? Five of the systems documented as Kepler-25, Kepler-27, Kepler-30, Kepler-31 and Kepler-33, are home to a set of planets whose orbits double each other. The outer body orbits twice for every inner body orbit. Four of the systems, Kepler-23, Kepler-24, Kepler-28 and Kepler-32, are home to a pairing where the outer planet circles the star twice for every three times the inner planet orbits.

“These configurations help to amplify the gravitational interactions between the planets, similar to how my sons kick their legs on a swing at the right time to go higher,” said Jason Steffen, the Brinson postdoctoral fellow at Fermilab Center for Particle Astrophysics in Batavia, Ill., and lead author of a paper confirming four of the systems.

And now for the game ball… Kepler-33 had the most planets of all. With a parent star older and more massive than Sol, the system gives rise to five planets whose sizes run between one and a half to five times the size of Earth. But, this is one crowded grouping. All of the planets orbiting this star are closer than Mercury is to our Sun! Thanks to stellar properties, Kepler is able to distinguish planets like these. The drop in the sun’s brightness and the length of time it takes for the planet to transit all play a role in determining presence. With similar signatures verified around the same star, chances of false readings are unlikely.

“The approach used to verify the Kepler-33 planets shows the overall reliability is quite high,” said Jack Lissauer, planetary scientist at NASA Ames Research Center at Moffett Field, Calif., and lead author of the paper on Kepler-33. “This is a validation by multiplicity.”

Original Story Source: NASA News Release.