Extrasolar Planets Archives

December 12, 2011December 24, 2015 by Paul Scott Anderson

The Habitable Exoplanets Catalog is Now Online!

Credit: The Habitable Exoplanets Catalog, Planetary Habitability Laboratory @ UPR Arecibo (phl.upl.edu)

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Anyone who has an interest in exoplanets probably knows about the various online catalogs that have become available in recent years, such as The Extrasolar Planets Encyclopaedia for example, providing up-to-date information and statistics on the rapidly growing number of worlds being discovered orbiting other stars. So far, these have been listings of all known exoplanets, both candidates and confirmed. But now there is a new catalog published by the Planetary Habitability Laboratory (a project of the University of Puerto Rico at Arecibo), which focuses exclusively on those planets which have been determined to be potentially habitable. The Habitable Exoplanets Catalog is a database which will serve as a key resource for scientists and educators as well as the general public.

As of right now, there are two confirmed planets and fourteen candidates listed, but those numbers are expected to grow over the coming months and years as more candidates are found and more of those candidates are confirmed. There is even a listing of habitable moons, whose existence have been inferred from the data, although none have been observed yet (finding exoplanets is challenging enough, but exomoons even more so!).

According to Abel Méndez, Director of the PHL and principal investigator, “One important outcome of these rankings is the ability to compare exoplanets from best to worst candidates for life.” He adds: “New observations with ground and orbital observatories will discover thousands of exoplanets in the coming years. We expect that the analyses contained in our catalog will help to identify, organize, and compare the life potential of these discoveries.”

The big question of course is whether any habitable planets are actually inhabited, two different things. To help answer that, it will be necessary to further analyze the atmospheres and surfaces of those planets, looking for any indication of possible biosignatures such as oxygen or methane. Kepler can’t do that directly, but subsequent telescopes such as the Terrestrial Planet Finder (TPF) will be able to, and provide a more accurate assessment of their physical composition, climate, etc.

Not long ago it wasn’t known if there even were any planets orbiting other stars; now we’re finding them by the thousands and soon we’ll be able to distinguish their unique physical characteristics and have a better idea of how many habitable worlds are out there – exciting times.

December 5, 2011December 24, 2015 by Paul Scott Anderson

Kepler Confirms First Planet in Habitable Zone of Sun-Like Star

This artist's illustration of Kepler 22-b, an Earth-like planet in the habitable zone of a Sun-like star about 640 light years (166 parsecs) away. Credit: NASA/Ames/JPL-Caltech

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Scientists from the Kepler mission announced this morning the first confirmed exoplanet orbiting in the habitable zone of a Sun-like star, the region where liquid water could exist on the surface of a rocky planet like Earth. Evidence for others has already been found by Kepler, but this is the first confirmation. The planet, Kepler-22b, is also only about 2.4 times the radius of Earth — the smallest planet found in a habitable zone so far — and orbits its star, Kepler-22, in 290 days. It is about 600 light-years away from Earth, and Kepler-22 is only slightly smaller and cooler than our own Sun. Not only is the planet in the habitable zone, but astronomers have determined its surface temperature averages a comfortable 22 degrees C (72 degrees F). Since the planet’s mass is not yet known, astronomers haven’t determined if it is a rocky or gaseous planet. But this discovery is a major step toward finding Earth-like worlds around other stars. A very exciting discovery, but there’s more…

It was also announced that Kepler has found 1,094 more planetary candidates, increasing the number now to 2,326! That’s an increase of 89% since the last update this past February. Of these, 207 are near Earth size, 680 are super-Earth size, 1,181 are Neptune size, 203 are Jupiter size and 55 are larger than Jupiter. These findings continue the observational trend seen before, where smaller planets are apparently more numerous than larger gas giant planets. The number of Earth size candidates has increased by more than 200 percent and the number of super-Earth size candidates has increased by 140 percent.

According to Natalie Batalha, Kepler deputy science team lead at San Jose State University in San Jose, California, “The tremendous growth in the number of Earth-size candidates tells us that we’re honing in on the planets Kepler was designed to detect: those that are not only Earth-size, but also are potentially habitable. The more data we collect, the keener our eye for finding the smallest planets out at longer orbital periods.”

Regarding Kepler-22b, William Borucki, Kepler principal investigator at NASA Ames Research Center at Moffett Field, California stated: “Fortune smiled upon us with the detection of this planet. The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season.”

Comparison of the Kepler-22 system with our own inner solar system. Credit: NASA/Ames/JPL-Caltech

Previously there were 54 planetary candidates in habitable zones, but this was changed to 48, after the Kepler team redefined the definition of what constitutes a habitable zone in order to account for the warming effects of atmospheres which could shift the zone farther out from a star.

The announcements were made at the inaugural Kepler science conference which runs from December 5-9 at Ames Research Center.

See also the press release from the Carnegie Institution for Science here.

November 28, 2011December 24, 2015 by Paul Scott Anderson

Life on Alien Planets May Not Require a Large Moon After All

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Ever since a study conducted back in 1993, it has been proposed that in order for a planet to support more complex life, it would be most advantageous for that planet to have a large moon orbiting it, much like the Earth’s moon. Our moon helps to stabilize the Earth’s rotational axis against perturbations caused by the gravitational influence of Jupiter. Without that stabilizing force, there would be huge climate fluctuations caused by the tilt of Earth’s axis swinging between about 0 and 85 degrees.

But now that belief is being called into question thanks to newer research, which may mean that the number of planets capable of supporting complex life could be even higher than previously thought.

Since planets with relatively large moons are thought to be fairly rare, that would mean most terrestrial-type planets like Earth would have either smaller moons or no moons at all, limiting their potential to support life. But if the new research results are right, the dependence on a large moon might not be as important after all. “There could be a lot more habitable worlds out there,” according to Jack Lissauer of NASA’s Ames Research Center in Moffett Field, California, who leads the research team.

It seems that the 1993 study did not take into account how fast the changes in tilt would occur; the impression given was that the axis fluctuations would be wild and chaotic. Lissauer and his team conducted a new experiment simulating a moonless Earth over a time period of 4 billion years. The results were surprising – the axis tilt of the Earth varied only between about 10 and 50 degrees, much less than the original study suggested. There were also long periods of time, up to 500 million years, when the tilt was only between 17 and 32 degrees, a lot more stable than previously thought possible.

So what does this mean for planets in other solar systems? According to Darren Williams of Pennsylvania State University, “Large moons are not required for a stable tilt and climate. In some circumstances, large moons can even be detrimental, depending on the arrangement of planets in a given system. Every system is going to be different.”

Apparently the assumption that a planet needs a large moon in order to be capable of supporting life was a bit premature. The results so far from the Kepler mission and other telescopes have shown that there is a wide variety of planets orbiting other stars, and so probably also moons, which we are now also on the verge of being able to detect. It’s nice to think that more of the terrestrial-type rocky planets, with or without moons, might be habitable after all.

November 24, 2011December 24, 2015 by Jon Voisey

Forget Exomoons. Let’s talk Exorings

An artist impression of an exomoon orbiting an exoplanet, could the exoplanet's wobble help astronomers? (Andy McLatchie)

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In an article earlier this month, I discussed the potential for discovering moons orbiting extrasolar planets. I’d used an image of an exoplant system with rings, prompting one reader to ask if those would be possible to detect. Apparently he wasn’t the only person wondering. A new paper looks more at exomoons and explores exoring systems.

The idea of detecting rings around distant planets dates back to at least 2004. Then, Barnes & Fortney suggested that rings would be potentially detectable from the eclipse they would cause if the photometric precision were as one part in ten-thousand. This is a big challenge, but one that’s more than met by telescopes like Kepler today. But for this to be possible, the rings needed to block the most light possible, meaning that they would have to be viewed face on, instead of edge on.

Fortunately, a study this year by Schlichting & Chang demonstrated that, even if the planet’s spin is aligned with the plane of orbit, it’s quite possible that the rings will be significantly warped due to gravitational interactions with the star.

So it should be possible, but what do astronomers need to look for?

The new paper attempts to answer this question by simulating light curves for a hypothetical ringed exoplanet. The first result is that the extra area of the star’s surface covered by the rings reduces the light detected. However, this is difficult to disentangle from the effects of simply having a larger planet that blocks the light.

Simulated light curve for exoplanet system with rings vs model lacking rings. Credit: Tusnski & Valio

A second effect is based on the shape of the light curve (a graph of the brightness as a function of time) as the planet begins and ends the transit. In short, the semi-transparent nature of the rings makes the drop in brightness softer, rounding off the edges of the light curve. When modeled against a planet that lacked rings, this would be readily detectable for an instrument like Kepler.

With such precision, the team suggests that Kepler should be more than capable of detecting a ring system similar in size and nature to those of Saturn. However, other transit finding telescopes, such as CoRoT, would mistake the rings for a slightly larger planet.

In the future, the team plans to take their model and reexamine data from Kepler and CoRoT to search for both rings and moons.

November 14, 2011December 24, 2015 by Jon Voisey

Exploring the Atmosphere of Exoplanet WASP-14b

Conceptual orbit of WASP 14b system. Credit: SuperWASP team

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First discovered in 2008, WASP 14b is an interesting exoplanet. It is roughly seven times as massive as Jupiter, but only 30% larger, making it among the densest known exoplanets. Recently, it was the target of observations from the Spitzer space telescope which was able to pick out the infrared radiation emitted by the planet and is giving astronomers new clues to how the atmospheres of Hot Jupiters function, contradicting expectations based on observations of other exoplanet atmospheres.

Images of the system were taken by a team of astronomers led by Jasmina Blecic and Joseph Harrington at the University of Central Florida. The team took images using three filters which allowed them to analyze the light at specific wavelengths. The brightness in each one was then compared to predictions made by models of atmospheres which included molecules such as H₂O, CO, CH₄, TiO, and VO as well as more typical atmospheric gasses like hydrogen, oxygen, and nitrogen.

While not having a large number of filters wouldn’t allow the team to conclusively match a specific model, they were able to confidently rule out some possible characteristics. In particular, the team rules out the presence of a layer of atmosphere that changes sharply in temperature from the regions directly around it, known as a “thermal inversion layer”. This comes as quite a surprise since observations of other hot Jupiters have consistently shown evidence of just such a layer. It was believed that all hot Jupiter type exoplanets should feature them if their atmospheres contained TiO or VO, molecules which filter out visible light. If they were present at a specific altitude, then that sudden layer of absorption would create a sudden shift in the temperature. The lack of this layer supports a 2009 study which suggested that such heavy molecules should settle out of the atmosphere and not be responsible for the thermal inversion layers. But this leaves astronomers with a fresh puzzle: If those molecules don’t cause them, then what does?

The team also found that the planet was brighter than expected when it was near the full phase which suggested that it is not as capable of redistributing its heat as some other exoplanets have been found to be. The team also confirmed that the planet has a notably elliptical orbit, despite being close to the star which should circularize the orbit. The astronomers that originally made the discovery of this planet postulated that this may be due to the presence of another planet which had a recent interaction that placed WASP 14b into its present orbit.

November 6, 2011December 24, 2015 by Jon Voisey

Forget Exoplanets. Let’s Talk Exomoons

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It wasn’t that long ago that astronomers began discovering the first planets around other stars. But as the field of exoplanetary astronomy explodes, astronomers have begun looking to the future and considering the possibility of detecting moons around these planets. Surprisingly, the potential for doing so may not be that far off.

Before exploring how we might detect satellites of distant planets, astronomers must first attempt to get an understanding of what they may be looking for. Fortunately, this question ties in well with the rapidly developing understanding of how solar systems form.

In general, there are three mechanisms by which planets may obtain satellites. The simplest is for them to simply form together from a single accretion disk. Another is that a massive impact may knock material off of a planet which forms into a satellite as astronomers believe happened with our own Moon. Some estimates have indicated that such impacts should be frequent and as many as 1 in 12 Earth like planets may have formed moons in this way. Lastly, a satellite may be a captured asteroid or comet as is likely for many of the moons of Jupiter and Saturn.

Each of these cases produces a different range of masses. Captured bodies are likely to be the smallest and therefor are unlikely to be detectable in the near future. Impact generated moons are expected to only be able to form bodies with 4% of the total mass of the planet and as such, are rather limited as well. The largest moons are thought to form in the disks around forming Jupiter like planets. These are the most likely to be detectable.

The first method by which astronomers may detect such moons is by the changes they would make in the wobble of the star that has been used to detect many extrasolar planets to date. Astronomers have already studied how a pair of binary stars may affect a binary star system may have on a third star it orbits. If the binary star is swapped out for a planet and a moon it turns out that the easiest systems to detect are massive moons that are distant from the planet, but close to the parent star. However, except in extreme cases, the amount of wobble that the pair could induce in the star is so small that it would be swamped by the convective motion of the star’s surface, making detection through this method nearly impossible.

Astronomers have begun detecting large numbers of exoplanets by transits, where the planet causes minor eclipses. Could astronomers also detect the presence of moons this way? In this case, the limit on detection would again be based on the size of the moon. Currently, the Kepler satellite is expected to detect planets similar in mass to Earth. If moons exist around a super-Jovian planet that are also similar in size to Earth, they too should be detected. However, forming moons this large is difficult. The largest moon in the solar system in Ganymede which is 40% of the diameter of Earth, putting it modestly below current detection thresholds, but potentially in reach of future exoplanet missions.

However, direct detection of the eclipses caused by transits isn’t the only way transits could be used to discover exomoons. In the past few years, astronomers have begun using the wobble of other planets on the ones they had already discovered to infer the existence of other planets in the system in the same way the gravitational tug of Neptune on Uranus allowed astronomers to predict Neptune’s existence before it was discovered. A sufficiently massive moon could cause detectable variations in when the transit of the planet would begin and end. Astronomers have already used this technique to place limits on the mass of potential moons around exoplanets HD 209458 and OGLE-TR-113b at 3 and 7 Earth masses respectively.

The first discovered exoplanet was discovered around a pulsar. The tug of this planet caused variation of the regular pulsation of the pulsar’s beat. Pulsars often beat hundreds to thousands of times per second and as such, are extremely sensitive indicators of the presence of planets. The pulsar PSR B1257+12 is known to harbor one planet that is a mere 0.04% the mass of Earth, which is well below the mass threshold of many moons. As such, variations in these systems, caused by moons would be potentially detectable with current technology. Astronomers have already used it to search for moons around the planet orbiting PSR B1620-26 and ruled out moons more than 12% the mass of Jupiter within half an Astronomical Unit (the distance between the Earth and Sun or 93 million miles) of the planet.

The last method by which astronomers have detected planets that could potentially be used for exomoons is direct observation. Since direct imaging of exoplanets has only become realized in the past few years, this option is likely still a ways off, but future missions like the Terrestrial Planet Finder Coronagraph may put it into the realm of possibility. Even if the moon is not fully resolved, the offset of the center of the dot of the pair may be detectable with current instruments.

Overall, if the explosion of knowledge on planetary systems continues, astronomers should be capable of detecting exomoons within the near future. The possibility already exists for some cases, like pulsar planets, but due to their rarity, the statistical likelihood of finding a planet with a sufficiently large moon is low. But as equipment continues to improve, making detection thresholds lower for various methods, the first exomoons should come into view. Undoubtedly, the first ones will be large. This will beg the question of what sorts of surfaces and potentially atmospheres they may have. In turn, this would inspire more questions about what life may exist.

Source:
The Detectability of Moons of Extra-Solar Planets – Karen M. Lewis

November 4, 2011December 24, 2015 by Paul Scott Anderson

Looking For the City Lights of Alien Civilizations

Artist's conception of city lights on an alien planet. Credit: David A. Aguilar (CfA)

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When most people think about the search for alien life, the first thing that usually pops into mind is SETI (Search for Extraterrestrial Intelligence). Primarily a search for extraterrestrial radio signals, another more recent facet of SETI is now looking for laser pulses as a conceivable means of communication across interstellar distances. But now, a third option has been presented: looking for sources of artificial light on the surfaces of exoplanets, like the lights of cities on Earth.

According to Avi Loeb at the Harvard-Smithsonian Center for Astrophysics, “Looking for alien cities would be a long shot, but wouldn’t require extra resources. And if we succeed, it would change our perception of our place in the universe.”

Like the other SETI initiatives, it relies on an assumption that an alien civilization would use technologies that are similar to ours or at least recognizable. That assumption itself has been the subject of contentious debate over the years. If an alien society was thousands or millions of years more advanced than us, would any of its technology even be recognizable to us?

That aside, how easy (or not) would it be to spot the signs of artificial lighting on an alien planet light-years away from us? The suggestion is to look at the changes in light from an exoplanet as it orbits its star. Artificial light would increase in brightness on the dark side of a planet as it orbits the star (as the planet goes through its phases, like our Moon or other planets in our own solar system), becoming more visible than any light that is reflected from the day side.

That type of discovery will require the next generation of telescopes, but today’s telescopes could test the idea, being able to find something similar as far out as the Kuiper Belt in our solar system, where Pluto and thousands of other small icy bodies reside. As noted by Edwin Turner at Princeton University, “It’s very unlikely that there are alien cities on the edge of our solar system, but the principle of science is to find a method to check. Before Galileo, it was conventional wisdom that heavier objects fall faster than light objects, but he tested the belief and found they actually fall at the same rate.”

The paper has been submitted to the journal Astrobiology and is available here.

November 2, 2011December 24, 2015 by Paul Scott Anderson

Kepler Space Telescope Mission Extension Proposal

Artist's conception of the Kepler 16 system, where the planet Kepler 16-b orbits two stars, much like Tatooine from Star Wars. Credit: NASA/JPL-Caltech/R. Hurt

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Some potentially good news for exoplanet fans, and Kepler fans in particular – Kepler scientists are asking for a mission extension and seem reasonably confident they will get it. Otherwise, funding is due to run out in November of 2012. It is crucial that Kepler receive renewed funding in order to continue its already incredibly successful search for planets orbiting other stars. Its primary goal — and the holy grail of exoplanet research — is finding worlds that are about the size of Earth, orbiting in the “habitable zone” of stars that are similar to our Sun, where temperatures could allow liquid water on their surfaces.

But finding those ideal smaller planets requires several years of observations, in order for Kepler to confirm a repeated orbit as a planet transits its star. The larger the orbit, the longer the observation time needed to view multilple transits. Most of the planetary candidates found already orbit much closer to their stars, hence taking less time to complete an orbit, and can more easily be detected within the first few years of the mission.

Kepler has already obtained very compelling data on a wide variety of planets since it was launched in 2009, with 1,235 candidates found so far (about 25 of which have been confirmed to date), but further refining of the data will take more time; a few more years would do just fine. The exciting trend has been that smaller, rocky planets appear to be much more common than gas giants; good news for those hoping to finds worlds similar to Earth that could be habitable (or, of course, inhabited!).

It is estimated it would cost about $20 million per year to keep Kepler functioning past 2012, which doesn’t sound too bad considering that about $600 million has already been invested in the mission. NASA’s budget, like everyone else’s, is tight though these days, so it isn’t a done deal yet.

The proposal will be submitted in January, with an answer expected by next April or May.

October 31, 2011December 24, 2015 by Paul Scott Anderson

Three New Planets and a Mystery Object Found Orbiting Dying Stars

A planet about to be consumed by its expanding red giant star. Credit: Mark Garlik/HELAS

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Some interesting new additions to the exoplanet family were announced last week by astronomers from Penn State University. While finding exoplanets these days may be considered “just another day at the office,” astronomers discovered three unique planets and an additional “mystery” object. What’s unique about these planets is the fact that the stars they orbit are all old and dying – red giant stars which have swollen up as they near the end of their lives, which ordinarily would consume any unlucky planets which may be too close to escape…

The three stars are HD 240237, BD +48 738, and HD 96127; the second one also has the mystery object orbiting it, which may be another planet, a low-mass star or a brown dwarf — something whose mass is in between that of a smaller, cooler star and a giant planet.

“We will continue to watch this strange object and, in a few more years, we hope to be able to reveal its identity,” said team leader, Alex Wolszczan.

Wolszczan was the first astronomer to discover exoplanets, three small planets orbiting a pulsar (neutron star) in 1992.

It is expected that our own Sun will also become a red giant star in another five billion years or so. Not a good thing for us obviously, but still a long ways off thankfully, since at that time, all of the inner planets of the solar system will probably be consumed by the expanding Sun.

The subject of planets orbiting dying stars will also be the focus of an upcoming conference, Planets Around Stellar Remnants, in Puerto Rico next January. It is organized by Penn State’s Center for Exoplanets and Habitable Worlds, and will take place exactly 20 years since Wolszczan made his discovery.

Interesting, since by far most of the exoplanets found so far orbit “normal” stars, like our Sun, which are still in mid-life or younger. But now, they’ve been observed around stars at all different stages of evolution, from the youngest stars, even those still with protoplanetary disks, to the oldest, stars which have already died and burned out, like pulsars. What this seems to indicate is that planets are a normal part of star formation, from beginning to end. The numbers now being found by astronomers, in the thousands and likely millions or billions, also suggest this; a big change from just a few decades ago when it was unknown if there were any other solar systems out there at all. There are, a lot of them.

Source: Penn State University

October 24, 2011December 24, 2015 by Gemma Lavender

“Baby” Planet Caught in the Act of Forming

The left image shows the transitional disk around the star LkCa 15. All of the light at this wavelength is emitted by cold dust in the disk. The hole in the centre indicates an inner gap with a radius of around 55 times the distance from the Earth to the Sun. The right image is an expanded view of the central part of the cleared region, illustrating a composite of two reconstructed images (blue: 2.1 micrometres, from November 2010; red: 3.7 micrometres) for LkCa 15. The location of the central star is also marked. Image: Kraus & Ireland 2011.

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Astronomers have taken a step closer to finding out how planetary systems form with the discovery of the ‘youngest’ planet ever found. LkCa 15 b is so young, it is still in the act of forming. This is the first direct image of a planet in the process of forming, and data indicates the planet is still being pieced together by gas and dust falling into its clutches from a cooler envelope that surrounds it.

The hot protoplanet orbits a star which possesses a mass comparable to our Sun, and is the youngest planetary system ever to be identified, with LkCa 15 aged at 2 million years, “We really have the age of the star and not the planet,” said Michael Ireland, a lecturer in astrophotonics at the Australian Astronomical Observatory. “The age of the star was determined by a great many people studying the gravitational contraction of both LkCa 15 and all of the other stars in the Taurus star forming region, which formed at nearly the same time.”

The observations were made by astronomers from the University of Hawaii and the Australian Astronomical Observatory using the keen eyesight of the twin 10-metre Keck telescopes located on the summit of Hawaii’s dormant Mauna Kea volcano.

For decades, astronomers have been aware that many young stars that pepper the Universe are shrouded by clouds of gas and dust. And since this realization they have enlisted the help of powerful infrared space observatories such as NASA’s Spitzer Space Telescope to peer into dusty cosmic regions that are hidden from optical telescopes.

Until now scientists had not been lucky enough to capture observations of new planets forming around these young stars, but thanks to the trickery of adaptive optics combined with ‘aperture mask interferometry’ that allows astronomers to resolve discs of dust around stars without the hindrance of dazzling starlight, imaging LkCa 15 b became possible. “It’s like we have an array of small mirrors,” said Adam Kraus of the University of Hawaii’s Institute for Astronomy. “We can manipulate the light and cancel out distortions.”

The location of LkCa 15 can be found using the above chart. Image: Adam Kraus/IAU/Sky & Telescope.

The astronomers have made the clever technique operable since 2008, which allowed them to search for gaps between stars and their protoplanetary dust discs where they figured planets are most likely to be lurking. In 2009 they were rewarded for their efforts as LkCa 15 b presented itself hugging its star, still bright from the energy of its formation. “LkCa 15 was only our second target and we immediately knew we were seeing something new,” said Kraus. “We could see a faint point source near the star, so thinking it might be a Jupiter-like planet we went back a year later to get more data.”

This hot, young world provides a view of the hellish birth of nascent planets.

“The protoplanet is heated up by its gravitational contraction energy,” said Ireland. “Gravitational potential energy is enough to make a truck’s brakes really hot when it goes down a mountain too fast. The potential energy of an entire planet being dropped onto itself is enough to make it glow red hot for millions of years. The planet is more than 1000 degrees Celsius – measuring its temperature more accurately is one of our goals next year. The dust and gas is mostly heated by the radiation field of the star and planet, and in equilibrium, reaches a temperature of less than 100 kelvins [-170 degrees Celsius].”

However, as the young planet pulls in more gas and dust onto itself, the astronomers can only guess as to how big this distant world could get. “The large outer disc around LkCa 15 still has about 55 Jupiter masses of material left in it,” said Ireland. “It is very difficult to estimate just how much of this material could end up on LkCa 15 b. If the orbit is nearly circular, and there is only one planet, then I believe that only a very small fraction of this matter could end up as part of LkCa 15 b. If I had to guess, I’d say around 10 times the mass of Jupiter for a final mass, with a little orbital migration to a closer orbit. However, we’ll get a better idea on this over the coming years with new theoretical models and after we see more of the orbit of the planet.”

The team’s paper can be found here.