Kepler Mission Archives

February 8, 2013December 23, 2015 by Nancy Atkinson

Less Than 1% of Exoplanet Systems Have Intelligent Life, Researchers Say

Recent findings say that Earth-like exoplanets could be all around us in our cosmic neighborhood. But how many would be home to intelligent life?

A new study estimates that fewer than 1% of transiting exoplanet systems host civilizations technologically advanced enough to send out radio transmissions that could be detected by our current SETI searches.

That equates to less than one in a million stars in the Milky Way Galaxy that would have intelligent life we could possibly communicate with. But even with those odds, there could be millions of advanced ET’s in the galaxy that we could phone, researchers say.

A group of astronomers, including Jill Tarter from the SETI Institute and scientists at the University of California, Berkeley used the Green Bank Telescope in West Virginia to look for intelligent radio signals from planets around 86 of stars where the Kepler mission has found transiting exoplanets. These specific targets were chosen because they had exoplanets in the habitable zone around the star and there were either five or more exoplanets in the system, or there was super-Earths with relatively long orbits.

The search came up empty in detecting any signals.

“We didn’t find ET, but we were able to use this statistical sample to, for the first time, put rather explicit limits on the presence of intelligent civilizations transmitting in the radio band where we searched,” said Andrew Siemion from UC Berkeley.

The team looked for signals in the 1-2 GHz range which is the region we use here on Earth for our cell phones and television transmissions. Narrowing it down, the team looked for signals that cover no more than 5Hz of the spectrum since there is no known natural mechanism for producing such narrow band signals.

“Emission no more than a few Hz in spectral width is, as far as we know, an unmistakable indicator of engineering by an intelligent civilization,” the team said in their paper.

The telescope spent 12 hours collecting five minutes of radio emissions from each star. Most of the stars were more than 1,000 light-years away, so only signals intentionally aimed in our direction would have been detected. The scientists say that in the future, more sensitive radio telescopes, such as the Square Kilometer Array, should be able to detect much weaker radiation, perhaps even unintentional leakage radiation, from civilizations like our own.

The researchers said these results allows them to put limits on the likelihood of Kardashev Type II civilizations. The Karashev scale is a method of measuring a civilization’s level of technological advancement, based on the amount of energy a civilization is able to utilize. The team said that finding no signals implies that the number of these civilizations that are “noisy” in the 1-2GHz range must less than one in a million per sun-like star.

The team plans more observations with the Green Bank Telescope, focusing on multi-planet systems in which two of the planets occasionally align relative to Earth, potentially allowing them to eavesdrop on communications between the planets.

“This work illustrates the power of leveraging our latest understanding of exoplanets in SETI searches,” said UC Berkeley physicist Dan Werthimer, who heads the world’s longest running SETI project at the Arecibo Telescope in Puerto Rico. “We no longer have to guess about whether we are targeting Earth-like environments, we know it with certainty.”

Read the team’s paper.

Sources: UC Berkeley, MIT Technology Review

February 6, 2013December 23, 2015 by Jason Major

Earthlike Exoplanets Are All Around Us

Artist's impression of a Jupiter-sized exoplanet orbiting an M-dwarf star

Artist’s impression of a rocky planet orbiting a red dwarf. Credit: David A. Aguilar (CfA)

We may literally be surrounded by potentially habitable exoplanets, according to new research by a team from the Harvard-Smithsonian Center for Astrophysics.

Using data gathered by NASA’s exoplanet-hunting Kepler spacecraft, the CfA researchers discovered that many red dwarf stars harbor planets, and some of those planets are rocky, Earth-sized worlds. Considering that red dwarfs, albeit optically dim, are the most abundant type of stars in our galaxy, this means that even a small percentage of them being host to Earthlike exoplanets puts the total number of potentially habitable worlds very high — and some of them could be right next door.

“We thought we would have to search vast distances to find an Earth-like planet,” said CfA astronomer and the paper’s lead author Courtney Dressing. “Now we realize another Earth is probably in our own backyard, waiting to be spotted.”

And our own backyard, in cosmic terms, could mean a mere 13 light-years away.

Our solar system is surrounded by red dwarfs. You can’t see them in the night sky because they are much too dim — less than a thousandth the brightness of the Sun. But they make up 75% of the stars in the local neighborhood, and based on the Kepler data the CfA team estimates that 6% of those red dwarfs likely have an Earth-sized planet in orbit around them.

And with at least 75 billion red dwarfs scattered across the galaxy… well, you do the math.*

“We now know the rate of occurrence of habitable planets around the most common stars in our galaxy,” said co-author David Charbonneau (CfA). “That rate implies that it will be significantly easier to search for life beyond the solar system than we previously thought.”

A visualization of the “unseen” red dwarfs in the night sky. Credit: D. Aguilar & C. Pulliam (CfA) See original here.

The conditions on a planet orbiting a red dwarf wouldn’t be exactly like Earth, of course. The planet would have to orbit rather closely to its star to be within its habitable zone, and would have to have a reasonably thick atmosphere to regulate heat and protect it from stellar outbursts. But one benefit to orbiting a red dwarf is that they have very long life spans — potentially longer than the current age of the Universe! So a habitable world around a red dwarf would literally have billions of years for life to evolve, thrive and develop on it.

“We might find an Earth that’s 10 billion years old,” Charbonneau said.

The team’s findings were presented today, Feb. 6, by Dressing during a press conference at the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA. The results will be published in The Astrophysical Journal. (Added 2/7/13: here’s the video of the press conference.)

CfA astronomers identified 95 planetary candidates circling red dwarf stars. Of those, three orbit within the habitable zone (marked in green) – the distance at which they should be warm enough to host liquid water on the surface. Those three planetary candidates (marked with blue dots) are 0.9, 1.4, and 1.7 times the size of Earth. Credit: C. Dressing (CfA)

Kepler Spacecraft Back in Action After Reaction Wheel Problem

Artist's concept of Kepler in action. NASA/Kepler mission/Wendy Stenzel.

There has been some concern about the Kepler spacecraft after one of the devices that provide the ability for super-precise pointing began misbehaving. Reaction wheels are devices which aim a spacecraft in different directions without firing rockets or jets, which reduces the amount of fuel a spacecraft needs; Kepler has four of them. Earlier this year, elevated friction was detected in reaction wheel #4, and so as a precaution for wheel safety, and as a measure to mitigate the friction, the reaction wheels were spun down to zero-speed and the spacecraft was placed in a thruster-controlled safe mode.

But now after a “rest” of the wheels for ten days, Kepler has now returned to science data collection beginning on January 28, 2013, and reaction wheel #4 seems to be operating normally, for now. During the 10-day resting safe mode, daily health and status checks with the spacecraft using NASA’s Deep Space Network were normal.

This is of special concern because last year, reaction wheel #2 failed. Kepler scientists say the spacecraft needs at least three wheels must operate until at least 2016 for Kepler to achieve its prime objective of finding Earth-like planets around sun-like stars. Last year, NASA approved an extended mission for Kepler through 2016, and so a lot is riding on the health of the spacecraft’s reaction wheels.

During much of the mission, ground controllers have observed intermittent friction on wheel # 4. Wheel # 2, on the other hand, showed no problems until early 2012, and it failed several months later.

“Since the failure of reaction wheel #2 in July 2012, the performance of the spacecraft on three wheels has been excellent,” said Kepler Project Manager Roger Hunter, writing an update on the Kepler website, noting that when reaction wheel #2 began to fail, it also exhibited elevated and somewhat chaotic friction.

“Reaction wheel #4 has been something of a free spirit since launch, with a variety of friction signatures, none of which look like reaction wheel #2, and all of which disappeared on their own after a time,” Hunter said. “Resting the wheels can provide an opportunity for the lubricant in the bearings to redistribute and potentially return the friction to nominal levels. Over the next month, the engineering team will review the performance of reaction wheel #4 before, during, and after the safe mode to determine the efficacy of the rest operation.”

As Emily Lakdawalla noted in one of the Weekly Space Hangouts, engineers are getting creative in how to deal with hardware issues in spacecraft, and compared the Kepler team’s approach to “resting” the reaction wheel to how engineers working with the Spirit Mars rover came up with the plan to have the rover drive backwards when one of the wheels started acting up, and the lubricant lasted longer when the wheel was used in the opposite direction.

Engineers for Kepler have implemented additional procedures to extend the lives of the reaction wheels, including running the wheels at warmer temperatures and alternating their spin directions.

Kepler was launched in March 2009, and is in an Earth-trailing solar orbit. It is pointed toward constellations Cygnus and Lyra, observing a 10-degree-wide field containing at least 4.5 million stars. Kepler is focusing on approximately 156,000 stars for the purposes of its research. Kepler scientists have found 105 new planets around other stars, and the mission’s data archive has evidence for more than 2,700 planet candidates.

January 14, 2013December 23, 2015 by Jason Major

A Moon With Two Suns: Making Art from Science

A view of Kepler 47c and binary stars. ©Digital Drew. All rights reserved.

What would it look like on a hypothetical icy moon orbiting the exoplanet Kepler 47c? Perhaps something like this.

This is an illustration by an artist who goes by the name Digital Drew on Flickr. Drew creates landscapes of imagined alien worlds orbiting stars (and sometimes planets) that actually exist in the Universe. With 3D software, a little science and a lot of imagination, Drew shows us what skies might look like on other planets.

Kepler 47c (KOI-3154.02) is a Neptune-sized exoplanet orbiting a binary star pair 4,600 light-years away. It is part of the first circumbinary system ever discovered — one of at least two planets orbiting a pair of stars. In the image here, Kepler 47c is seen at upper left.

What makes this exoplanet so exciting is that it is within the habitable zone around the stellar pair. So even though the planet itself may be a gas giant and thus not particularly suitable for life, any moons it has in orbit just might be.

While its slightly smaller planetary companion Kepler 47b orbits much too closely to the twin suns for water to exist as a liquid, 47c’s orbit is much farther out, completing one revolution every 303 days. Mainly illuminated by a star like our Sun but about 15% dimmer, this is a region where you could very well find a large rocky moon with conditions similar to Earth’s.

Fly a spacecraft over its higher elevations and you just might see a scene like this, a double sunset over a glacier-filled valley with a crescent gas giant dominating the sky. (Makes one wonder what the balmier regions might look like!)

“Unlike our sun, many stars are part of multiple-star systems where two or more stars orbit one another. The question always has been — do they have planets and planetary systems? This Kepler discovery proves that they do. In our search for habitable planets, we have found more opportunities for life to exist.”

– William Borucki, Kepler mission principal investigator (Sept. 2012)

And as more giant planets are discovered within their system’s habitable zones, the more there’s a chance that habitable moons could exist — or perhaps even be more common than habitable planets! Just recently the citizen science project Planet Hunters announced the potential exoplanet PH2 b, a Jupiter-sized world that orbits within a habitable zone. In our Solar System Jupiter has lots of moons; PH2 b could very well have a large number of moons of its own, any number of them with liquid water on their surfaces and temperatures “just right” for life.

While it will likely be quite some time before we see any direct observations of an actual exomoon, and possibly never from one, we must rely on the work of artists like Digital Drew to illustrate the many possibilities that exist.

See more of Drew’s work on his Flickr page here, and read more about the discovery of the Kepler 47 system here.

Inset image: Diagram of the Kepler 47 system compared to the inner Solar System. Credit: NASA/JPL-Caltech/T. Pyle.

January 7, 2013December 23, 2015 by Jason Major

Kepler Finds Hundreds of New Exoplanet Candidates

Artist’s depiction of the Kepler 10 system, which contains planets 2.2 and 1.4 times the size of Earth. (NASA/Ames/JPL-Caltech)

Kepler mission scientists announced today the discovery of literally hundreds of new exoplanet candidates — 461, to be exact — orbiting distant stars within a relatively small cross-section of our galaxy, bringing the total number of potential planets awaiting confirmation to 2,740. What’s more, at least 4 of these new candidates appear to be fairly Earth-sized worlds located within their stars’ habitable zone, the orbital “sweet spot” where surface water could exist as a liquid.

Impressive results, considering that NASA’s planet-hunting spacecraft was launched a little under 4 years ago (and watching 150,000 stars to spot the shadows of planets is no easy task!)

“… the ways by which men arrive at knowledge of the celestial things are hardly less wonderful than the nature of these things themselves.”

— Johannes Kepler

Since the last official announcement of Kepler candidates in Feb. 2012 the number of smaller Earth- and super-Earth-sized worlds observed has risen considerably, as well as the identification of multi-planet systems that are organized more-or-less along a flat plane… just like ours.

“There is no better way to kickoff the start of the Kepler extended mission,” said Kepler scientist Christopher Burke, “than to discover more possible outposts on the frontier of potentially life bearing worlds.”

From the NASA press release:

Since the last Kepler catalog was released in February 2012, the number of candidates discovered in the Kepler data has increased by 20 percent and now totals 2,740 potential planets orbiting 2,036 stars. The most dramatic increases are seen in the number of Earth-size and super Earth-size candidates discovered, which grew by 43 and 21 percent respectively.

The new data increases the number of stars discovered to have more than one planet candidate from 365 to 467. Today, 43 percent of Kepler’s planet candidates are observed to have neighbor planets.

The most dramatic increases are seen in the number of Earth-size and super Earth-size candidates discovered, which grew by 43 and 21 percent respectively. (NASA)

Although some of the new candidates announced today are large Neptune-sized planets, more than half are Earth- to super-Earth sized worlds less than twice the radius of our own planet.

In order for Kepler candidates to be “officially” called exoplanets, they must be observed 3 times on a regular orbit — that is, their signature dimming of the light from their home star must occur as predicted once their presence and then orbital period is calculated. Only then is an exoplanet confirmed.

To date Kepler has confirmed 105 exoplanets.

The longer the mission continues, the better the chance that Kepler will be able to confirm smaller Earth-sized worlds in longer-period orbits.

“The analysis of increasingly longer time periods of Kepler data uncovers smaller planets in longer period orbits — orbital periods similar to Earth’s,” said Steve Howell, Kepler mission scientist. “It is no longer a question of will we find a true Earth analogue, but a question of when.”

Scientists analyzed more than 13,000 transit-like signals called ‘threshold crossing events’ to eliminate known spacecraft instrumentation and astrophysical false positives, phenomena that masquerade as planetary candidates, to identify the potential new planets. Watch the video below to see how Kepler observes the light-curve of transit events.

Read more on the NASA press release, and learn more about the Kepler mission here.

January 7, 2013December 23, 2015 by Nancy Atkinson

Nearly All Sun-Like Stars Have Planetary Systems

A new analysis examined the frequencies of planets of different sizes based on findings from NASA's Kepler spacecraft, correcting for both incompleteness and false positives. The results show that one in six stars has an Earth-sized planet in a tight orbit. Credit: F. Fressin (CfA)

The latest analysis of data from the Kepler planet-hunting spacecraft reveals that almost all stars have planets, and about 17 percent of stars have an Earth-sized planet in an orbit closer than Mercury. Since the Milky Way has about 100 billion stars, there are at least 17 billion Earth-sized worlds out there, according to Francois Fressin of the Harvard-Smithsonian Center for Astrophysics (CfA), who presented new findings today in a press conference at the American Astronomical Society meeting in Long Beach, California. Moreover, he said, almost all Sun-like stars have planetary systems.

The holy grail of planet-hunting is finding a twin of Earth – a planet of about the same size and in the habitable zone around similar star. The odds of finding such a planet is becoming more likely Fressin said, as the latest analysis shows that small planets are equally common around small and large stars.

While the list of Kepler planetary candidates contains majority of the knowledge we have about exoplanets, Fressin said the catalog is not yet complete, and the catalog is not pure. “There are false positives from events such as eclipsing binaries and other astrophysical configurations that can mimic planet signals,” Fressin said.

By doing a simulation of the Kepler survey and focusing on the false positives, they can only account for 9.5% of the huge number of Kepler candidates. The rest are bona-fide planets.

This artist's illustration represents the variety of planets being detected by NASA's Kepler spacecraft. Credit: C. Pulliam & D. Aguilar (CfA)

Altogether, the researchers found that 50 percent of stars have a planet of Earth-size or larger in a close orbit. By adding larger planets, which have been detected in wider orbits up to the orbital distance of the Earth, this number reaches 70 percent.

Extrapolating from Kepler’s currently ongoing observations and results from other detection techniques, it looks like practically all Sun-like stars have planets.

The team then grouped planets into five different sizes. They found that 17 percent of stars have a planet 0.8 – 1.25 times the size of Earth in an orbit of 85 days or less. About one-fourth of stars have a super-Earth (1.25 – 2 times the size of Earth) in an orbit of 150 days or less. (Larger planets can be detected at greater distances more easily.) The same fraction of stars has a mini-Neptune (2 – 4 times Earth) in orbits up to 250 days long.

Larger planets are much less common. Only about 3 percent of stars have a large Neptune (4 – 6 times Earth), and only 5 percent of stars have a gas giant (6 – 22 times Earth) in an orbit of 400 days or less.

The researchers also asked whether certain sizes of planets are more or less common around certain types of stars. They found that for every planet size except gas giants, the type of star doesn’t matter. Neptunes are found just as frequently around red dwarfs as they are around sun-like stars. The same is true for smaller worlds. This contradicts previous findings.

“Earths and super-Earths aren’t picky. We’re finding them in all kinds of neighborhoods,” says co-author Guillermo Torres of the CfA.

Planets closer to their stars are easier to find because they transit more frequently. As more data are gathered, planets in larger orbits will come to light. In particular, Kepler’s extended mission should allow it to spot Earth-sized planets at greater distances, including Earth-like orbits in the habitable zone.

Kepler detects planetary candidates using the transit method, watching for a planet to cross its star and create a mini-eclipse that dims the star slightly.

Sources: Harvard Smithsonian CfA, AAS Press Conference

October 16, 2012December 23, 2015 by Nancy Atkinson

Extreme Solar Systems: Why Aren’t We Finding Other Planetary Systems Like Our Own?

Artist concept of a previous multi-planet solar system found by the Kepler spacecraft. Credit: NASA/Tim Pyle

Most planetary systems found by astronomers so far are quite different than our own. Many have giant planets whizzing around in a compact configuration, very close to their star. An extreme case in point is a newly found solar system that was announced on October 15, 2012 which packs five — count ‘em — five planets into a region less than one-twelve the size of Earth’s orbit!

“This is an extreme example of a compact solar system,” said researcher Darin Ragozzine from the University of Florida, speaking at a press conference at the American Astronomical Society’s Division for Planetary Sciences meeting. “If we can understand this one, hopefully we can understand how these types of systems form and why most known planetary systems appear different from our own solar system.”

This new system, currently named KOI-500, was found with data from the Kepler planet-finding spacecraft, and Ragozzine said astronomers have now uncovered a new realm of exo-planetary systems.

“The real exciting thing is that Kepler has found hundreds of stars with multiple transiting planets,” he said. “These are the most information-rich systems, as they can tell you not only about the planets, but also the architecture of how solar systems are put together.”

The fact that almost all solar systems found so far are vastly different than our own has astronomers wondering if we are, in fact, the oddballs. A study from 2010 concluded that only about 10 – 15 percent of stars in the Universe host systems of planets like our own, with terrestrial planets nearer the star and several gas giant planets in the outer part of the solar system.

Part of the reason our dataset of exoplanets is skewed with planets that are close to the star is because currently, that is all we are capable of detecting.

But the surprising new population of planetary systems discovered in the Kepler data that contain several planets packed in a tiny space around their host stars does give credence to the thinking that our solar system may be somewhat unique.

However, perhaps KOI-500 used to be more like our solar system.

“From the architecture of this planetary system, we infer that these planets did not form at their current locations,” Ragozzine said. “The planets were originally more spread out and have ‘migrated’ into the ultra-compact configuration we see today.”

There are several theories about the formation of the large planets in our outer solar system which involves the planets moving and migrating inward and outward during the formation process. But why didn’t the inner planets, including Earth, move in closer, too?

“We don’t know why this didn’t happen in our solar system,” Ragozzine said, but added that KOI-500 will “become a touchstone for future theories that will attempt to describe how compact planetary systems form. Learning about these systems will inspire a new generation of theories to explain why our solar system turned out so differently.”

A few notes of interest about KOI-500:

The five planets have “years” that are only 1.0, 3.1, 4.6, 7.1, and 9.5 days.

“All five planets zip around their star within a region 150 times smaller in area than the Earth’s orbit, despite containing more material than several Earths (the planets range from 1.3 to 2.6 times the size of the Earth). At this rate, you could easily pack in 10 more planets, and they would still all fit comfortably inside the Earth’s orbit,” Ragozzine noted. KOI-500 is approximately 1,100 light-years away in the constellation Lyra, the harp.

Four of the planets orbiting KOI-500 follow synchronized orbits around their host star in a completely unique way — no other known system contains a similar configuration. Work by Ragozzine and his colleagues suggests that planetary migration helped to synchronize the planets.

“KOI” stands for Kepler Object of Interest, and Ragozzine’s findings on this system have not yet been published, and so the system has yet to officially be considered a confirmed planetary system. “Every time we find something like this we give it a license-plate-like number starting with KOI,” Ragozzine said.

When does a KOI become an official planet? Ragozzine said the process is by confirming and validating the data. “Basically you need to prove statistically or by getting a specific measurement that it is not some other astronomical signal,” he said.

This infographic from Space.com supplies more visual details:

Sources: AAS, University of Florida

October 15, 2012April 26, 2016 by Nancy Atkinson

Citizen Planet Hunters Find a Planet in a Four-Star System

A family portrait of the PH1 planetary system that was discovered in part due to crowdsourcing. Image Credit: Haven Giguere/Yale.

A family portrait of the PH1 planetary system: The newly discovered planet is depicted in this artist’s rendition transiting the larger of the two eclipsing stars it orbits. Off in the distance, well beyond the planet orbit, resides a second pair of stars bound to the planetary system. Image Credit: Haven Giguere/Yale.

A planet has been discovered orbiting in a four-star system — and no, that doesn’t mean the accommodations and conditions are excellent. It literally means four stars, where a planet is orbiting a binary star system that in turn is orbited by a second distant pair of stars. This is the first system like this that has ever been found, and its discovery demonstrates the power of citizen scientists, as it was found by a joint effort of amateurs participating on the Planet Hunters website under the guidance of professional astronomers.

This is might be an extremely rare planetary setup, astronomer Meg Schwamb from Yale says, as only six planets are currently known to orbit two stars, and none of these are orbited by other stellar companions. Astronomers are calling the newly found world a ‘circumbinary’ planet.

“Circumbinary planets are the extremes of planet formation,” said Schwamb, Planet Hunters scientist and lead author of a paper about the system presented Oct. 15 at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society in Reno, Nevada. “The discovery of these systems is forcing us to go back to the drawing board to understand how such planets can assemble and evolve in these dynamically challenging environments.”

The planet is called PH1, for the first confirmed planet identified by the Planet Hunters citizen scientists, but it has the nickname of Tatooine, the planet in Star Wars that orbited two suns.

Planet Hunters uses data from the Kepler spacecraft, specially designed for looking for signs of planets.

The volunteers, Kian Jek of San Francisco and Robert Gagliano of Cottonwood, Arizona, spotted faint dips in light caused by the planet as it passed in front of its parent stars, a common method of finding extrasolar planets. Schwamb, a Yale postdoctoral researcher, led the team of professional astronomers that confirmed the discovery and characterized the planet, following observations from the Keck telescopes on Mauna Kea, Hawaii. PH1 is a gas giant with a radius about 6.2 times that of Earth, making it a bit bigger than Neptune.

“Planet Hunters is a symbiotic project, pairing the discovery power of the people with follow-up by a team of astronomers,” said Debra Fischer, a professor of astronomy at Yale and planet expert who helped launch Planet Hunters in 2010. “This unique system might have been entirely missed if not for the sharp eyes of the public.”

PH1 orbits outside the 20-day orbit of a pair of eclipsing stars that are 1.5 and 0.41 times the mass of the Sun. This planet is dense — it has perhaps about 170 times more mass than Earth — and is about half the diameter of Jupiter. It revolves around its host stars roughly every 138 days. Beyond the planet’s orbit at about 1000 AU (roughly 1000 times the distance between Earth and the Sun) is a second pair of stars orbiting the planetary system.

Gagliano, one of the two citizen scientists involved in the discovery, said he was “absolutely ecstatic to spot a small dip in the eclipsing binary star’s light curve from the Kepler telescope, the signature of a potential new circumbinary planet, ‘Tatooine,’ and it’s a great honor to be a Planet Hunter, citizen scientist, and work hand in hand with professional astronomers, making a real contribution to science.”

Jek expressed wonder at the possibility of the discovery: “It still continues to astonish me how we can detect, let alone glean so much information, about another planet thousands of light years away just by studying the light from its parent star.”

Read the paper here.

Source: Planet Hunters

September 26, 2012April 26, 2016 by Jason Major

Researchers Present the Sharpest Image of Pluto Ever Taken from Earth

A “speckle image” reconstruction of Pluto and its largest moon, Charon (Gemini Observatory/NSF/NASA/AURA)

Real planet, dwarf planet, KBO, who cares? What matters here is that astronomers have created the sharpest image of Pluto ever made with ground-based observations — and developed a new way to verify potential Earth-like exoplanets at the same time.

Here’s how they did it:

After taking a series of quick “snapshots” of Pluto and Charon using a recently-developed camera called the Differential Speckle Survey Instrument (DSSI), which was mounted on the Gemini Observatory’s 8-meter telescope in Hawaii, researchers combined them into a single image while canceling out the noise caused by turbulence and optical aberrations. This “speckle imaging” technique resulted in an incredibly clear, crisp image of the distant pair of worlds — especially considering that 1. it was made with images taken from the ground, 2. Pluto is small, and 3. Pluto is very, very far away.

Read: Why Pluto is No Longer a Planet

Less than 3/4 the diameter of our Moon, Pluto (and Charon, which is about half that size) are currently circling each other about 3 billion miles from Earth — 32.245 AU to be exact. That’s a long way off, and there’s still much more that we don’t know than we do about the dwarf planet’s system. New Horizons will fill in a lot of the blanks when it passes close by Pluto in July 2015, and images like this can be a big help to mission scientists who want to make sure the spacecraft is on a safe path.

“The Pluto-Charon result is of timely interest to those of us wanting to understand the orbital dynamics of this pair for the 2015 encounter by NASA’s New Horizons spacecraft,” said Steve Howell of the NASA Ames Research Center, who led the Gemini imaging study.

See images of Pluto taken by Hubble here.

In addition, the high resolution achievable through the team’s speckle imaging technique may also be used to confirm the presence of exoplanet candidates discovered by Kepler. With an estimated 3- to 4-magnitude increase in imaging sensitivity, astronomers may be able to use it to pick out the optical light reflected by a distant Earth-like world around another star.

Speckle imaging has been used previously to identify binary star systems, and with the comparative ability to “separate a pair of automobile headlights in Providence, RI, from San Francisco, CA” there’s a good chance that it can help separate an exoplanet from the glare of its star as well.

The research was funded in part by the National Science Foundation and NASA’s Kepler discovery mission, and will be published in the journal Publications of the Astronomical Society of the Pacific in October 2012. Read more here.

Main image: the first speckle reconstructed image for Pluto and Charon from which astronomers obtained not only the separation and position angle for Charon, but also the diameters of the two bodies. North is up, east is to the left, and the image section shown is 1.39 arcseconds across. Resolution of the image is about 20 milliarcseconds rms. Credit: Gemini Observatory/NSF/NASA/AURA. Inset: the Gemini North telescope on the summit of Mauna Kea. (Gemini Observatory)

August 17, 2012December 23, 2015 by Jason Major

What If All of Kepler’s Exoplanets Orbited the Same Star?

That’s exactly the scenario shown by a mesmerizing animation called “Worlds” by Alex Parker — a single system containing 2299 multiple-transit planetary candidates identified to date by NASA’s Kepler space telescope, which is currently scrutinizing a field of view within the constellation Cygnus to detect the oh-so-faint reductions in brightness caused by planets passing in front of their stars.

The search requires patience and precision; it’s not really this crowded out there.

Alex’s animation takes 2299 candidates that have been observed multiple times, each shown to scale in relation to their home star, and puts them in orbit around one star, at their relative distances.

The result, although extravagantly impossible, is no less fascinating to watch. (I suggest going full screen.)

“The Kepler observatory has detected a multitude of planet candidates orbiting distant stars,” Alex writes on his Vimeo page. “The current list contains 2321 planet candidates, though some of these have already been flagged as likely false-positives or contamination from binary stars. This animation does not contain circumbinary planets or planet candidates where only a single transit has been observed, which is why ‘only’ 2299 are shown.

“A fraction of these candidates will likely be ruled out as false positives as time goes on, while the remainder stand to be confirmed as real planets by follow-up analysis,” Alex adds.

The white ellipses seen when the animation pulls back are the relative sizes of the orbits of Mercury, Venus and Earth.

At this time the Kepler mission has identified 2321 planetary candidates, with 74 exoplanets confirmed. See more on the Kepler mission here.

Animation: Alex Parker. Image: Kepler mission planet candidates family portrait (NASA Ames/Jason Rowe/Wendy Stenzel)