The two newest planets spied by the Kepler space telescope are locked in a forever back-and-forth.

When Kepler’s scientists saw a star 2,000 light years away dim slightly, they knew there was the chance it was the telltale signature of a planet passing in front. But when the calculations were done and the confirmation came in, they found a surprise—what they’d seen was actually two planets transiting in front of the star.

NASA says it’s the first time they’ve ever caught such a sight, and today the scientists officially announced the finding with a study in Science. While other studies have found multiple planets around a single star–in fact, it happened earlier this week–those studies have used different planet-detection techniques like the wobble method.

The two worlds, both gas giants, do more than orbit the same star on the same plane, though. They push and pull each other in a motion that keeps the two exoplanets close to arithmetic celestial perfection. Kepler-9B, the larger, orbits the star in 19.24 days on average, the astronomers saw. Kepler-9c, the smaller, completes a revolution in an average of 38.91 days. But every time the scientists checked, 9b’s orbit was getting 4 minutes longer, while 9c’s shrank by 39 minutes.

(more…)

In August 2006, Pluto received its official demotion to dwarf planet status, taking our solar system down to eight planets. In August 2010, exoplanet hunters say they’ve found a haul of new worlds around a single star; that alien solar system may have seven known planets, meaning the system could be more like our home system than any ever discovered. And one of those worlds could be the smallest exoplanet ever found, too.

The star these planets orbit is called HD 10180, and it lies 127 light years from here. Astronomers at the European Southern Observatory in Chile used a spectrograph called HARPS to track tiny variations in the starlight caused by the pull of the planets.

It found clear evidence for five giant planets similar in size to Uranus or Neptune in our own solar system. But there were also tantalising signs that two other planets are also present, one of which would be the smallest, or least-massive, yet found orbiting another star [Christian Science Monitor].

(more…)

Although some publications glossed over the uncertainty in announcing the first findings of the planet-hunting Kepler mission, researchers say the overall point remains true: Earth-like planets (meaning that they’re small and rocky, not that they have aliens writing blogs about science) are not only not rare–they’re the most common type of planet in our galaxy.

The first intimations of this news came out a few days ago in reports like the Daily Mail’s, which blared that NASA’s planet-hunting Kepler mission had found 140 new planets that were like the Earth in size, and that worlds like our own could dominate the Milky Way. That claim came after a presentation now available to view online by one of the scientists behind Kepler, Harvard’s Dimitar Sasselov.

But Sasselov and colleagues responded to Space.com, trying to quell some of the excitement–or at least hedge on the exact magnitude of the find:

“What Dimitar presented was ‘candidates,’” said David Koch, the mission’s deputy principal investigator at NASA’s Ames Research Center in Moffett Field, Calif. ”These have the apparent signature we are looking for, but then we must perform extensive follow-up observations to eliminate false positives, such as background eclipsing binaries. This requires substantial amounts of ground-based observing which is done primarily in the summer observing season” [Space.com]

(more…)

We know about exoplanet HD 209458b, nicknamed “Osiris.” We know it’s 153 light years away, that it has water in its atmosphere, and that it orbits its star in three and a half days at a distance 100 times closer than Jupiter is to the sun. But we didn’t know this for sure until now: This planet has a tail.

In a study in The Astrophysical Journal, a research team says Osiris, a gas giant, orbits so close that its star is blasting away its atmosphere. As the planet progresses on its blazing hot and hasty revolutions, a tail like that of a comet follows behind it. The Hubble Space Telescope‘s Cosmic Origins Spectrograph caught the effect as Osiris made repeated transits in front of its star.

The instrument detected the heavy elements carbon and silicon in the planet’s super-hot 2,000 degrees F (1,100 C or so) atmosphere. This detection revealed the parent star is heating the entire atmosphere, dredging up the heavier elements and allowing them to escape the planet.

Jeffrey Linsky, of the University of Colorado, who led the study, said: “We have measured gas coming off the planet at specific speeds, some coming toward Earth. The most likely interpretation is that we have measured the velocity of material in a tail” [Christian Science Monitor].

(more…)

The most violent winds in our own solar system whip around the Great Dark Spot of Neptune at 1,200 miles per hour, making the worst storms here on Earth look like kid stuff. But when astronomers trained their telescopes on one of the longest-studied planets around another star, suddenly even Neptune didn’t look so impressive. This week in Nature, astronomers say that the exoplanet HD 209458 b has a super-storm whose winds rage at 3,000 to 6,000 mph.

The exoplanet (which we’ll call by its friendlier nickname, Osiris) sits 150 light years from here, in the neighborhood of the constellation Pegasus. It’s an old friend, too. Osiris was the first exoplanet seen transiting in front of its star back in 1999. A decade later, though, with technology a decade more advanced, the team could spy on Osiris with the a spectrometer at the Very Large Telescope in Chile and track its carbon monoxide signature.

In fact, the VLT’s data is so good that the astronomers could see not only the planet’s orbital speed, but also the relative speed of the gas on its surface, according to study author Ignas Snellen.

“We see this clear change in velocity” of HD 209458 b, Snellen says. “There’s also an offset—the gas during the transit seems to be moving toward us.” The carbon monoxide appears to be flowing at two kilometers per second, or roughly 7,000 kilometers [~4,350 miles] per hour [Scientific American].

(more…)

It’s the 1840s. Rival astronomers in Britain and France separately toil away in their notebooks, fiercely guarding their calculations of just where a planet beyond Uranus might be hiding, hoping that they and their country will get the glory for finding it. When telescopes finally spot Neptune, the discovery leads to decades of debate over primacy, and scouring each man’s private data to determine who deserved the most credit.

Fast forward to the 21st century: Rivalries may have changed, but in the hunt for new planets—especially becoming the first to detect a new world like our own in a distant star system—defending one’s data to lay claim to discovery has not gone away.

This week the team behind NASA‘s planet-hunting space telescope, Kepler, announced that it has found more than 700 new candidates for exoplanets. Given that the current tally of known planets beyond our solar system stands near 460, that’s a huge announcement. But what’s drawn some attention is that more than half of the candidates won’t be released publicly at this time. These include smallest planet candidates—those closest to our own world in size—which won’t be officially announced until February 2011.

It’s no secret why:

(more…)

It’s the size of Jupiter, orbits at about the distance of Mercury, and isn’t too far from the temperature range of Earth. Meet Corot-9b, the newest find in the cavalcade of exoplanets and the one its discoverers say is most like the worlds of our own solar system.

“Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium,” said team member Tristan Guillot of the Côte d’Azure Observatory in Nice, France. “And it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures” [Space.com]. The large group of astronomers reporting the find in Nature estimate the planet’s temperature at a range between just below zero and slightly above 300 degrees Fahrenheit. It completes an orbit in 95 days, though it’s about 1,500 light years away.

(more…)

As the count of known planets in distant star systems continues to grow (the number now exceeds 400), so too does the number of ways we have to learn about them. Reporting in Nature this week, a team of astronomers say they have measured the makeup of an exoplanet‘s atmosphere using an Earth-based telescope for the first time.

Mark Swain’s team directed NASA’s Infrared Telescope Facility toward HD 189733 b, a planet 63 light years away, discovered back in 2005. HD 189733 b was already known from space-borne observations to harbor several specific molecules in its atmosphere: water, methane, carbon dioxide and carbon monoxide [Scientific American]. Swain’s analysis confirmed those previous findings using spectrography, in which the light from an object is broken down into its component wavelengths, allowing the identification of atoms or molecules by their unique emission or absorption properties [Scientific American]. Swain’s team also turned up something else—a spike in emissions at a very particular wavelength of light, 3.3 microns, that the earlier observations didn’t detect and that Swain’s team can’t explain–at least not yet.

(more…)

Once, most of exoplanets that astronomers spotted were giants, but now they’re seeing more and more new planets with masses not far off from the Earth’s. One of those newly found Earth-like exoplanets, however, may not have always been so similar to our own world: An astronomer made the case last week that the small, sweltering planet was once a mighty gas giant that shrank.

Astronomers discovered Corot-7b in September. Its diameter is roughly 1.7 times that of Earth. Based on its size and mass, its density is similar to Earth’s, indicating that it is a rocky Earth-like orb [ABC News]. But the comparisons end there. While it’s rocky like Earth, this fiery hellhole is no place for life. It orbits its star at a distance of only 1.6 million miles (we’re presently at a much more comfortable 93 million miles from our sun) and completes a revolution in only 20 hours’ time. And, NASA’s Brian Jackson argued at last week’s American Astronomical Society meeting, Corot-7b is probably just a shell of its former self, and once was a type of gas giant called a “hot Jupiter.”

(more…)

NASA’s new eye in the sky has spotted the first handful of what it hopes will be a flood of new exoplanets. The Kepler telescope, launched last year with the express purpose of planet-hunting, has found its first five new worlds, with the results forthcoming in the journal Science this week. Just don’t get any ideas about living on any of them.

“One of the planets is amazingly light – like Styrofoam,” said William J. Borucki, the astronomer from NASA’s Ames Research Center…. “And all five simply glow,” he said, “they’re like looking into a blast furnace – but that’s simply no place to look for life” [San Francisco Chronicle]. The scalding-hot planets measure in excess of 2,000 degrees Fahrenheit, hotter than molten lava. These planets all orbit their stars in a hurry, taking between three and five days to make a circuit. Ground measurements confirmed Kepler’s findings.

(more…)

And the exoplanet count marches on. A few days ago astronomers announced they had found a handful of new planets around sun-like stars, some only 29 light years away. Now, in a study published today in Nature, a team led by David Charbonneau unveils a new super-Earth that’s hot, watery, and only 2.68 times the size of our own world.

The planet currently bares the name GJ 1214b, and while Charbonneau says it’s probably not habitable (because of the 400-degree Fahrenheit surface temperature), it’s not too far off the mark. Geoffrey W. Marcy, a planet hunter from the University of California, Berkeley, wrote in an accompanying article in Nature that the new work provided “the most watertight evidence so far for a planet that is something like our own Earth, outside our solar system” [The New York Times].

(more…)

As the tally of known planets beyond our solar system continues to grow, so does the number of them that look familiar—planets close to Earth’s size around stars that resemble our sun. Today astronomers announced that they’ve found a new batch of planets that not only fit that description but also reside in our cosmic neighborhood.

Three planets with masses ranging from 5.3 to 24.9 Earth masses were found orbiting the star 61 Virginis, which is 28 light years from Earth in the constellation of Virgo [Herald Sun]. That star can be seen with the naked eye under dark skies, and team member Chris Tinney says the system is strikingly like our own, noting that Neptune is only 17 Earth masses. In addition, NASA’s Spitzer Space Telescope recently found a ring of dust around 61 Virginis that’s about twice the distance from that star as Pluto is from our sun. The region between the newly discovered planets and that disk remains unexplored, the astronomers say, and could be the home of even more planets.

(more…)

The quest to find a second Earth–a potentially habitable planet that’s about the size of our home, but that lies in a distant solar system–has hit a snag. The Kepler space telescope was expected to be well on its way to detecting Earth-sized exoplanets by now, but an electronic glitch is slowing it down. The delays are caused by noisy amplifiers in the telescope’s electronics. The team is racing to fix the issue by changing the way data from the telescope is processed, but the delay could mean that ground-based observers now have the upper hand in the race to be the first to spot an Earth twin [Nature News].

Kepler, which was launched in March, uses the transit method to detect exoplanets; it’s watching a patch of 100,000 stars in hopes of detecting the brief dimming of a star’s light, which indicates that a planet has passed in front of the star. Kepler focuses light onto 42 light-detecting chips, called CCDs, each of which monitors stars in a different part of the telescope’s field of view. Each CCD is split into two for the purposes of sending data back to Earth, for a total of 84 data channels. Three of these channels are plagued by electronic noise that makes stars in their field of view appear to flicker – “like it’s changing its brightness at a rapid rate”, says Kepler chief scientist William Borucki [New Scientist]. That’s awkward, since the artificial flickers could obscure the real dimming that occurs during a planet’s transit.

(more…)

Planets, planets, everywhere! Astronomers have announced the discovery of 32 new planets orbiting distant stars, bringing the list of known exoplanets up to more than 400. The batch of freshly discovered worlds include four that are only five or six times the mass of Earth, an encouraging sign in the quest for a truly Earth-like world that could support life. Researcher Stephane Udry says the discovery is exciting because it suggests that low-mass planets could be numerous in our galaxy. “From [our] results, we know now that at least 40% of solar-type stars have low-mass planets. This is really important because it means that low-mass planets are everywhere, basically” [BBC News].

The discovery was made with the HARPS telescope at the European Southern Observatory‘s facility in Chile. HARPS uses the so-called wobble method to detect planets, in which researchers look for the slight quiver in a star’s regular movements that indicates the gravitational tug of an orbiting planet.

Planets were found around a surprising variety of star types. Gas giant planets were found orbiting “metal-poor” stars — those lacking in elements other than hydrogen and helium — which until now had been considered unlikely places for planets to form [Washington Post]. Researchers also located four exoplanets around relatively cool, small stars known as M-class red dwarfs, and will continue to examine such stars for signs of Earth-like planets. The team expects to keep spotting planets by the dozen, says Udry: “Nature doesn’t like a vacuum so if there is space to put a planet it will put a planet there” [Reuters].

Related Content:
80beats: Study: Strange Planet Has Atmosphere of Gaseous Rock—and It Rains Pebbles
80beats: Rock Solid Evidence of a Rocky, Earth-like Exoplanet
80beats: New Telescope Could Reveal a Milky Way Packed With Habitable Planets
DISCOVER: How Long Until We Find a Second Earth?

Image: European Southern Observatory. Artist’s impression of a newly discovered planet orbiting the star Gliese 667 C, which is part of a triple star system.

The exoplanet Corot-7b has earned a reputation as one of the most interesting planets yet spotted outside our solar system, mostly because of its similarities to Earth: Astronomers have determined that it’s rocky, like Earth, and it’s only about five times more massive than our home planet. But the dissimilarities are just as fascinating. In the latest twist, a new study has suggested that storm fronts on Corot-7b may bring a rain of pebbles.

The alien planet is extraordinarily close to its parent star, and researchers think that it’s tidally locked so that one hemisphere always faces the star’s blasting heat. On that side, temperatures are thought to reach about 4,220 degrees Fahrenheit—hot enough to vaporize rock. So unlike the much cooler Earth, COROT-7b has no volatile gases (carbon dioxide, water vapor, nitrogen) in its atmosphere. Instead it’s atmosphere consists of what might be called vaporized rock. “The only atmosphere this object has is produced from vapor arising from hot molten silicates in a lava lake or lava ocean” [SPACE.com], says study coauthor Bruce Fegley Jr.

(more…)