Posted on 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)

Posted on by VirtualAstro

British TV Audience Discovers Potential New Planet

Planet Holmes Credit: BBC

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A public “mass participation” push initiated on a UK television program to find planets beyond our Solar System has had an immediate result! On Monday, January 16, 2012 “BBC Stargazing LIVE” began its first of three nights of television programs live from Jodrell Bank Observatory in the UK. The series was hosted by Professor Brian Cox, comedian Dara O’Briain along with a number of other well known TV personalities, astronomers and scientists. There was even a guest appearance via satellite link from Captain Gene Cernan, the last man on the Moon.

As well as the main TV program, there were numerous local events across the UK and the viewers could “mass participate” in activities such as looking for extra solar planets with the citizen science project, Planethunters.org.

The website hosts data gathered by NASA’s Kepler space telescope, and asks volunteers to sift the information for anything unusual that might have been missed in a computer search. People are especially adept at seeing things that computers do not and the BBC Stargazing Live event was a golden opportunity to get many people looking. During the event, over a million classifications were made and 34 candidate planets found on the website in 48 hours.

On the last show of the series on Wednesday 18th January it was announced, that in particular, one planet candidate looks extremely promising, as it has been identified multiple times by PlanetHunter participants.

The planet is circling the star SPH10066540 and is described as being similar in size to Neptune, circles its parent every 90 days and is about a similar distance from its parent star as Mercury is from our Sun. It could be described as a hot Neptune.

Chris Holmes from Peterborough UK and Lee Threapleton also from the UK found the planet by searching through time-lapsed images of stars looking for the periodic dips in brightness that result every time a planet passes in front of (transits) one of those stars.

Credit: planethunters.org

A transit has to be observed several times before a planet will be confirmed. For the orange dwarf star SPH10066540, five such events have now been seen in the Kepler data making it a strong candidate for an extra solar planet.

“There’s more work to be done to confirm whether these candidates are true planets,” wrote the PlanetHunters team on their blog, “in particular, we need to talk to our friends on the Kepler team – but we’re on our way.”

The NASA Kepler space telescope, launched in 2009, has been searching a part of space thought to have many stars similar to our own Sun.

You can try and find a new planet too by visiting planethunters.org it is incredibly simple and easy to do and requires no previous knowledge of astronomy.

How many more planets will be discovered?

Posted on by Paul Scott Anderson

Tatooine the Sequel: Kepler Finds Two More Exoplanets Orbiting Binary Stars

Artist's conception of the Kepler-35 system. Lynette Cook / extrasolar.spaceart.org

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For exoplanet fans, this week has been an exciting one, with some amazing new discoveries being announced at the American Astronomical Society meeting in Austin, Texas – our galaxy is brimming with planets, probably billions, and the smallest known planets have been found (again), with one about the size of Mars. But that’s not all; it was also announced that Kepler has found not one but two more planets orbiting binary stars!

The two star systems are Kepler-34 and Kepler-35; they consist of double stars which orbit each other and are about 4,900 and 5,400 light-years from Earth. The two new planets, Kepler-34b and Kepler-35b, each orbit one of these pairs of stars and are both about the size of Saturn. Since they orbit fairly close to their stars, they are not in the habitable zones; Kepler 34-b completes an orbit in 289 days and Kepler-35b in 131 days. It’s more the fact that they orbit double stars that makes them so interesting.

This is now the third planet found in a binary star system. The first, Kepler-16b, was nicknamed Tatooine as it was reminiscent of the world orbiting two suns in the Star Wars films. Until recently, it was unknown if any such star systems had planetary companions. It was considered possible, although unlikely, and remained only a theory. But now, the view is that there may indeed be a lot of them out there, just as planets are now apparently common around single stars. That’s good news for planet-hunters, as most stars in our galaxy are binaries.

According to William Welsh of San Diego State University who participated in the study, “This work further establishes that such ‘two sun’ planets are not rare exceptions, but may in fact be common, with many millions existing in our galaxy. This discovery broadens the hunting ground for systems that could support life.”

Eric B. Ford, associate professor of astronomy at the University of Florida, stated: “We have long believed these kinds of planets to be possible, but they have been very difficult to detect for various technical reasons. With the discoveries of Kepler-16b, 34b and 35b, the Kepler mission has shown that the galaxy abounds with millions of planets orbiting two stars.”

The hope now is that Kepler will continue until 2016 to be able to further refine its findings so far. That will require a mission extension, but scientists involved are optimistic they will get it.

According to Ford, “Astronomers are practically begging NASA to extend the Kepler mission until 2016, so it can characterize the masses and orbits of Earth-size planets in the habitable zone. Kepler is revolutionizing so many fields, not just planetary science. It would be a shame not to maximize the scientific return of this great observatory. Hopefully common sense will prevail and the mission will continue.”

Yes, indeed.

The study was published January 11, 2012 in the journal Nature (payment or subscription required for access to full article).

See also PhysOrg.com for a good overview of the new findings.

Posted on by Paul Scott Anderson

Analysis of the First Kepler SETI Observations

Example of signals KOI 817 and KOI 812. Credit: The Search for Extra Terrestrial Intelligence at UC Berkeley

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As the Kepler space telescope begins finding its first Earth-sized exoplanets, with the ultimate goal of finding ones that are actually Earth-like, it would seem natural that the SETI (Search for Extraterrestrial Intelligence) program would take a look at them as well, in the continuing search for alien radio signals. That is exactly what SETI scientists are doing, and they’ve started releasing some of their preliminary results.

They are processing the data taken by Kepler since early 2011; some interesting signals have been found (a candidate signal is referred to as a Kepler Object of Interest or KOI), but as they are quick to point out, these signals so far can all be explained by terrestrial interference. If a single signal comes from multiple positions in the sky, as these ones do, it is most likely to be interference.

They do, however, also share characteristics which would be expected of alien artificial signals.

A couple of examples are from KOI 817 and KOI 812. They are of a very narrow frequency, as would be expected from a signal of artificial origin. They also change in frequency over time, due to the doppler effect – the motion of the alien signal source relative to the radio telescope on Earth. If a signal is found with these characteristics but also does not appear to be just interference, that would be a good candidate for an actual artificial signal of extraterrestrial origin.

These are only the results of the first observations and many more will come during the next weeks and months.

Looking for signals has always been like looking for a needle in the cosmic haystack; until now we were searching pretty much blind, starting even before we knew if there were any other planets out there or not. What if our solar system was the only one? Now we know that it is only one of many, with new estimates of billions of planets in our galaxy alone, based on early Kepler data. Plus the fact that the majority of those are thought to be smaller, rocky worlds like Earth, Mars, etc. How many of them are actually habitable is still an open question, but finding them narrows down the search, providing more probable actual targets to turn the radio telescopes toward instead of just trying to search billions of stars overall.

All twelve signal examples so far can be downloaded here (PDF).

Posted on 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.

Posted on by Ray Sanders

How Common are Terrestrial, Habitable Planets Around Sun-Like Stars?

Artst concept of the Kepler telescope in orbit. Credit: NASA

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Once again news from the Kepler mission is making the rounds, this time with a research paper outlining a theory that Earth-like planets may be more common around class F, G and K stars than originally expected.

In the standard stellar classification scheme, these type of stars are similar or somewhat similar to our own Sun (which is a Class G star); Class F stars are hotter and brighter and Class K stars are cooler and dimmer. Given this range of stars, the habitable zones vary with different stars. Some habitable planets could orbit their host star at twice the distance Earth orbits our Sun or in the case of a dim star, less than Mercury’s orbit.

How does this recent research show that small, rocky, worlds may be more common that originally thought?

Dr. Wesley Traub, Chief Scientist with NASA’s Exoplanet Exploration Program outlines his theory in a recent paper submitted to the Astrophysical Journal.

A possible habitable world? Credit: NASA/JPL

Based on Traub’s calculations in his paper, he formulates that roughly one-third of class F, G, and K stars should have at least one terrestrial, habitable-zone planet. Traub bases his assertions on data from the first 136 days of Kepler’s mission.

Initially starting with 1,235 exoplanet candidates, Traub narrowed the list down to 159 exoplanets orbiting F class stars, 475 orbiting G class stars, and 325 orbiting K class stars – giving a total of 959 exoplanets in his model. For the purposes of Traub’s model, he defines terrestrial planets as those with a radius of between half and twice that of Earth. The mass ranges specified in the model work out to between one-tenth Earth’s mass and ten times Earth’s mass – basically objects ranging from Mars-sized to the theoretical super-Earth class.

The paper specifies three different ranges for the habitable zone: A “wide” habitable zone (HZ) from 0.72 to 2.00 AU, a more restrictive HZ from 0.80 to 1.80 AU, and a narrow/conservative HZ of 0.95 to 1.67 AU.

After working through the necessary math of his model, and coming up with a “power law” that gives a habitable zone to a star depending on its class and then working out how many planets ought to be at those distances, Traub estimated the frequency of terrestrial, habitable-zone planets around Sun-like (Classes F, G and K) stars at (34 ± 14)%.

He added that mid-size terrestrial planets are just as likely to be found around faint stars and bright ones, even though fewer small planets show up around faint stars. But that is likely because of the limits of our currently technology, where small planets are more difficult for Kepler to see, and it’s easier for Kepler to see planets that orbit closer to their stars.

Traub discussed how the quoted uncertainty is the formal error in projecting the numbers of short-period planets, and that the true uncertainty will remain unknown until Kepler observations of orbital periods in the 1,000-day range become available.

Check out our previous coverage of exoplanet detections using the Kepler data at: http://www.universetoday.com/89120/big-find-citizen-scientists-discover-two-extrasolar-planets/

If you’d like to read Traub’s paper and follow the math involved in his analysis, you can do so at: http://arxiv.org/PS_cache/arxiv/pdf/1109/1109.4682v1.pdf

Learn more about the Kepler mission at: http://kepler.nasa.gov/

Source: arXiv:1109.4682v1 [astro-ph.EP]

Posted on by Jason Major

Shedding Some Light on a Dark Discovery

Artist's rendering of TrES-2b, an extremely dark gas giant. Credit: David Aguilar (CfA)

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Earlier this month astronomers released news of the darkest exoplanet ever seen: discovered in 2006, the gas giant TrES-2b reflects less than 1% of the visible light from its parent star… it’s literally darker than coal! Universe Today posted an article about this intriguing announcement on August 11, and now Dr. David Kipping of the Harvard-Smithsonian Center for Astrophysics is featuring a podcast on 365 Days of Astronomy in which he gives more detail about the dark nature of this discovery.

Listen to the podcast here.

The 365 Days of Astronomy Podcast is a project that will publish one podcast per day, for all 365 days of 2011. The podcast episodes are written, recorded and produced by people around the world.

“TrES-2b is similar in mass and radius to Jupiter but Jupiter reflects some 50% of the incident light. TrES-2b has a reflectivity less than that of any other planet or moon in the Solar System or beyond. The reflectivity is significantly less than even black acrylic paint, which makes the mind boggle as to what a clump of this planet would look like in your hand. Perhaps an appropriate nickname for the world would be Erebus, the Greek God of Darkness and Shadow. But what really is causing this planet to be so dark?”

– Dr. David Kipping

David Kipping obtained a PhD in Astrophysics from University College London earlier this year. His thesis was entitled ‘The Transits of Extrasolar Planets with Moons’ and David’s main research interest revolves around exomoons. He is just starting a Carl Sagan Fellowship at the Harvard-Smithsonian Center for Astrophysics.

The paper on which the the podcast is based can be found here.

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Jason Major is a graphic designer, photo enthusiast and space blogger. Visit his website Lights in the Dark and follow him on Twitter @JPMajor and on Facebook for more astronomy news and images!

Posted on by Jason Major

Astronomers Discover a Dark Alien World

Artist's rendering of TrES-2b, an extremely dark gas giant. Credit: David Aguilar (CfA)

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An exoplanet has been discovered by astronomers that reflects less than one percent of the light it receives from its parent star. Less reflective than black acrylic paint, this planet is literally darker than coal!

TrES-2b is a Jupiter-sized gas giant orbiting the star GSC 03549-02811, about 750 light-years away in the direction of the constellation Draco. First discovered in 2006 by the Trans-Atlantic Exoplanet Survey (TrES), its unusual darkness has been identified by researchers led by David Kipping from the Harvard-Smithsonian Center for Astrophysics (CfA) and David Spiegel from Princeton University, using data from NASA’s Kepler spacecraft.

Kepler has located more than 1,200 planetary candidates in its field of view. Additional analysis will reveal whether any other unusually dark planets lurk in that data. (Image: NASA/Kepler mission/Wendy Stenzel)

The team monitored the brightness of the TrES-2 system as the planet orbited its star and detected a subtle dimming and brightening due to the planet’s changing phase. A more reflective planet would have shown larger brightness variations as its phase changed.

The dark exoplanet is tidally locked with its star and orbits it at a distance of only 5 million kilometers (3.1 million miles), keeping it heated to a scorching 1000º C (1,832º F). Too hot for the kinds of reflective ammonia clouds seen on Jupiter, TrES-2b is wrapped in an atmosphere containing light-absorbing chemicals like vaporized sodium and potassium, or gaseous titanium oxide. Still, this does not completely explain its extremely dark appearance.

“It’s not clear what is responsible for making this planet so extraordinarily dark,” stated co-author David Spiegel of Princeton University. “However, it’s not completely pitch black. It’s so hot that it emits a faint red glow, much like a burning ember or the coils on an electric stove.”

Regardless of its faint glow TrES-2b is still much darker than any planet or moon in our solar system.

The new work appears in a paper in the journal Monthly Notices of the Royal Astronomical Society. Read the news release here.

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Jason Major is a graphic designer, photo enthusiast and space blogger. Visit his website Lights in the Dark and follow him on Twitter @JPMajor and on Facebook for more astronomy news and images!

Posted on by Jason Major

Multi-Planet Systems Common in Kepler Findings

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

 

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Of the 1235 planetary candidates that NASA’s Kepler space telescope has found so far, 408 reside in multiple-planet systems – a growing trend that indicates planets do, in fact,  like company.

The systems observed also seem to behave quite differently than our own solar system. In particular many are flatter than ours; that is, the planets orbit their stars in more or less the same exact plane. This, of course, is what allows Kepler to see them in the first place… the planets have to transit their stars perpendicular to Kepler’s point of view in order for it to detect the oh-so-subtle change in brightness that indicates the likely presence of a planet. In our solar system there’s a variation in the orbital plane of some planets up to 7º – enough of a difference that an alien Kepler-esque telescope might very well not be able to spot all eight planets.

The reason for this relative placidity in exoplanet orbits may be due to the lack of gas giants like Jupiter in these systems. So far, all the multiple-planet systems found have planets smaller than Neptune. Without the massive gravitational influence of a Jupiter-sized world to shake things up, these exosystems likely experience a much calmer environment – gravitationally speaking, of course.

“Most likely, if our solar system didn’t have large planets like Jupiter and Saturn to have stirred things up with their gravitational disturbances, it would be just as flat. Systems with smaller planets probably had a much more sedate history.”

– David Latham, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA

Slide showing Kepler multi-planet systems (blue dots). Credit: David Latham.

Systems containing large gas giants have also been found but they are not as flat as those without, and many smaller worlds are indeed out there… “probably including a lot of them comparable in size to Earth,” said planet-hunter Geoff Marcy of the University of California, Berkeley.

While multiple-planet systems were expected, the scientists on the Kepler team were surprised by the amount that have been discovered.

“We didn’t anticipate that we would find so many multiple-transit systems. We thought we might see two or three. Instead, we found more than 100,” said Latham.

A total of 171 multiple-planet systems have been found so far… with many more to come, no doubt!

Announced yesterday at the American Astronomical Society conference in Boston, these findings are the result of only the first four months of Kepler’s observations. There will be another news release next summer but in the meantime the team wants time to extensively research the data.

“We don’t want to get premature information out. There’s still a lot of analysis that needs to be done.”

– Kepler principal investigator William Borucki

Read more on the Kepler mission site, or on Science NOW.

Posted on by Jason Major

Kepler Team Announces New Rocky Planet

Artist's impression of Kepler-10c (foreground planet)

 

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Today at the American Astronomical Society conference in Boston, the Kepler team announced the confirmation of a new rocky planet in orbit around Kepler-10. Dubbed Kepler-10c, this planet is described as a “scorched, molten Earth.”

2.2 times the radius of Earth, Kepler-10c orbits its star every 45 days. Both it and its smaller, previously-discovered sibling 10b are located too close to their star for liquid water to exist.

Kepler-10c was validated using a new computer simulation technique called “Blender” as well as additional infrared data from NASA’s Spitzer Space Telescope. This method can be used to locate Earth-sized planets within Kepler’s field of view and could also potentially help find Earth-sized planets within other stars’ habitable zones.

This is the first time the team feels sure that it has exhaustively ruled out alternative explanations for dips in the brightness of a star… basically, they are 99.998% sure that Kepler-10c exists.

The Kepler-10 star system is located about 560 light-years away near the Cygnus and Lyra constellations.

Read the release on the Nature.com blog.

Image credit: NASA/Ames/JPL-Caltech