With the American Astronomical Society meeting now wrapped up in Washington, we're left to mull over the highlights, particularly the Kepler results. But the Keck Observatory also contributed compelling exoplanet news in the form of HD156668b, a planet some eighty light years from earth in the direction of Hercules. Working with Keck data, a research team led by Andrew Howard (University of California at Berkeley) has brought us a world that is only four times the mass of Earth, making this 'super Earth' the second smallest exoplanet yet discovered. Addendum: See andy's note below re planets smaller than this one. More on the 'pulsar planets' here. Using the HIRES instrument (High Resolution Echelle Spectrograph) and the 10-meter Keck I telescope at Mauna Kea, the astronomers teased out the presence of the planet through radial velocity methods, which are responsible for the great majority of the planets thus far discovered. The trick is to work down to smaller and smaller worlds...

William Borucki's talk about the early Kepler findings on Monday created the biggest spike in traffic I've ever seen on Centauri Dreams, enough to blow through our memory allocation and crash the site for about twenty minutes. I had to reboot the server and up the memory to get back online, a tribute to the interest Kepler continues to generate in our community. I'm also getting plenty of comments from people at the American Astronomical Society meeting in Washington. If you use Twitter, use the hashtag #aas to join the ongoing stream of short updates. Right now Scott Gaudi's talk on Tuesday is generating the biggest buzz. Gaudi (Ohio State) reported on a gravitational microlensing effort called MicroFUN (Microlensing Follow-Up Network), one we've previously discussed in these pages. The method is well understood: One star occults another as seen from Earth. The light of the more distant star is magnified by the nearer one, and any planets around the lensing star momentarily boost...

Just how good is Kepler at finding planets? We're getting a pretty good idea. In his talk yesterday at the AAS meeting in Washington, William Borucki (NASA Ames) showed a plot of the lightcurve for previously known planet HAT-P-7. The signature of the planetary transit is unmistakable in these data, a well defined dip in the starlight as HAT-P-7 makes the star just a little dimmer by its passage. Kepler's sensitivity is apparent. But the plot is more fascinating still, for in addition to the well defined signature that denotes the dip in starlight caused by the planet moving across the face of the star, Kepler also saw a second dip. That one was caused by the light of the planet being blocked by the star itself. It's a tiny dip, but one readily demonstrated in Borucki's chart, and it tells us that Kepler is living up to expectations in terms of finding faint signals. We all hope, of course, for a future finding, the faint signal of a terrestrial world, preferably one in the habitable...

The American Astronomical Society's 215th national meeting will involve some 3,500 attendees, with more than 2,200 scientific presentations on the program, but this morning the buzz is all about Kepler and the early results to be announced today. William Borucki (NASA Ames) spoke at 0830 to announce the first planets discovered by Kepler, five exoplanets (none smaller than Neptune), that include what appears to be a highly irradiated 'Neptune' and a second planet (Kepler 7b) that is the least dense world ever discovered, with a density similar to styrofoam. It, along with three other new exoplanets, gives us insight into planets with densities substantially lower than what we expect from gas giants. Borucki also described another unusual find, Jupiter-sized objects that are hotter than the stars they orbit. A live stream from the AAS is available here, and a Twitter stream at #aas. The paper from Borucki et al. will be published online by Science on Thursday January 7. Later today,...

Several stories stick in my mind as we approach the New Year, presented here in no particular order, but merely as material for musing. The detection (by the MEarth Project) of a transiting 'super-Earth' this past month opens up interesting areas for speculation. Gliese 1214b is roughly 6.5 times as massive as Earth, orbiting an M-dwarf some forty light years from our Solar System. You'll recall we discussed this one in terms of possible study of its atmosphere. Abundant Small Worlds On the always interesting systemic site, Greg Laughlin notes that the orbital period of this planet is a mere 1.58 days. In fact, the planet is separated from the system barycenter by 0.014 AU, which turns out to be the smallest separation yet measured for any planet. What stands out here is the density of the red dwarf. Says Laughlin: "Gliese 1214 is more than twice as dense as lead. The density of the Sun, on the other hand, is bubblegum by comparison." The result: a planet/star separation that isn't...

With much of the US east coast to the north of me digging out from the recent storm, I can only think how fortunate I am not to be trying to travel right now. The snow-clogged airports and snarled streets that are all over the news do have their effect on my thinking, though, which may be why I was reminded this morning of a much colder place, a certain Saturnian moon whose most recent image now offers yet more proof of the active hydrology going on there. Titan got a bit lost in the shuffle here late last week but I don't want to ignore this compelling new image. What we're looking at is the flash of sunlight reflecting off one of Titan's lakes. It's not a huge surprise, given that we've identified lake-shaped basins that ought to have been ideal for liquid methane. But now that the Sun is directly illuminating the northern lakes as spring breaks out on that part of Titan, we can take advantage of conditions there to see things like this, taken with Cassini's visual and infrared...

What a welcome event the release of James Cameron's new film Avatar must be for scientists working on the question of exomoons -- satellites orbiting extrasolar planets. Imagine being a Lisa Kaltenegger (CfA) or David Kipping (University College London), hard at work exploring exomoon detection and possible habitability when a blockbuster film is released that posits a habitable moon around a gas giant. The film's exomoon, called Pandora, fits a scenario that exomoon hunters tell us could exist, orbiting a giant planet in the habitable zone of its star, and it draws public attention as never before to exoplanet and exomoon detections. Interesting exomoon scenarios beyond gas giants are also possible, as this image shows. We're learning that we can detect exomoons using tools like transit time duration measurements, and there are other methods, too, like microlensing and distortions of the Rossiter-McLaughlin effect. A paper from Kipping that we examined here recently makes the case...

Picking up on yesterday's theme of planetary detections from ground-based observatories, we now get word of the detection of a transiting 'super-Earth' -- one that may well have an atmosphere we can study -- with the kind of equipment many amateurs already use to observe the sky. The new world is GJ 1214b, about 6.5 times as massive as the Earth, orbiting a small M-dwarf about a fifth the size of the Sun some forty light years from Earth. But there's more, a good deal more. At a distance of 1.3 million miles, the planet orbits its star every 38 hours, with an estimated temperature a little over 200 degrees Celsius. Because GJ 1214b transits the star, astronomers are able to measure its radius, which turns out to be 2.7 times that of Earth. The density derived from this suggests a composition of about three-fourths water and other ices and one-fourth rock. Some of the planet's water should be in the form of exotic materials like Ice VII, a crystalline form of water that is found at...

What jumps out at the reader when examining yesterday's exoplanet news is not so much that we've found as many as six low-mass planets, but that the two stars involved are both near twins of the Sun. Steven Vogt (UC-Santa Cruz) and Paul Butler (Carnegie Institution of Washington) led this work, and Vogt is quick to point out that two of the planets are 'super-Earths,' the first we've ever found around stars so similar to our own. Vogt notes this has implications for the broader hunt for planets that could sustain life: "These detections indicate that low-mass planets are quite common around nearby stars. The discovery of potentially habitable nearby worlds may be just a few years away." A Bonanza Around 61 Virginis And Sun-like they are, these stars. 61 Virginis, 28 light years from Earth, has long fascinated astrobiologists because it is more similar to the Sun than any of our nearest neighbors in terms of age, mass and other properties. Moreover, a separate team working with the...

We don't exactly know what to call GJ 758 B, which may be a brown dwarf or simply a large planet of between ten and forty Jupiter masses. But the detection is being hailed as the first direct observation of a 'planet-like object' orbiting a star similar to our own Sun. We have the new High Contrast Coronagraphic Imager with Adaptive Optics (HiCIAO), recently attached to the Subaru Telescope and working in the near infrared, to thank for the detection. Image: The August 2009 discovery image of GJ758 B and C, taken with Subaru HiCIAO in the near infrared wavelength. Without angular differential imaging, the star's speckle halo (burst-like feature in the center) would overwhelm the signals from the planet candidates. Credit: Subaru Telescope/NAOJ. Masking the star's intense light and using a technique known as angular differential imaging, HiCIAO seems to promise great things in the way of future direct detections of exoplanets, where the object is directly seen rather than having its...

You won't want to miss an interview with Debra Fischer now available on the MarketSaw site. The latter is a blog focused on 3D motion pictures, and thus the interest in Fischer's work on Alpha Centauri draws from a cinematic base. Specifically, James Cameron's new movie Avatar depicts a gas giant with a habitable moon around it, and the MarketSaw editors are interested in whether such a planet could exist around one of the Centauri stars. The interview that follows, discussing Fischer's ongoing hunt for Centauri planets, is prime reading. I'll quote from it, but you'll want to read the whole thing (thanks to Vincenzo Liguori for the tip). As to the gas giant question, we can answer that one quickly. Neither Centauri A nor Centauri B is orbited by a gas giant. We know this because enough data have accumulated on the question to rule such planets out. Stable orbits, says Fischer, don't reach out much further than 2 AU around either star, and the lack of gas giants leaves smaller worlds...

To the two ongoing hunts for planets around the Alpha Centauri stars we can now add a third. John Hearnshaw (University of Canterbury, Christchurch) reports in a recent post on Cosmic Diary that the university's Mt. John Observatory has begun a program to search for Earth-mass planets around Centauri A and B. Although the observatory is heavily invested in microlensing technologies (working with the Microlensing Observations in Astrophysics collaboration), the new efforts will put radial velocity methods to work using the Hercules spectrograph. The program is a joint effort with Stuart Barnes at the Anglo-Australian Observatory and Mike Endl at the University of Texas (Austin). And as Hearnshaw notes, the problem is a formidable one, given that an Earth-mass planet in the habitable zone around Centauri A creates a 'wobble' of only 10 cm/s (slightly larger for the less massive Centauri B). Yet the observatory is banking on Hearnshaw's statement that 30,000 spectra of Centauri A or B...

The goal of detecting a terrestrial class exoplanet has burned bright in the imagination ever since the discovery of the first planets orbiting main sequence stars. In a recent SEED Magazine story, Lee Billings (one of the most graceful science writers now working) harkens back to then NASA administrator Daniel Goldin's 1996 speech at the American Astronomical Society meeting in San Antonio, Texas. Goldin talked about seeing Earth-like exoplanets up close, speculating that in 25 years we might be able to obtain images with a resolution to see clouds, continents and oceans. I'm going to use a different Goldin quote than Lee did, from a later speech, but the idea is clear enough in either iteration. Here Goldin is speaking about the classrooms of the mid-21st Century and what they might look like: When you look on the walls, you see a dozen maps detailing the features of Earth-like planets orbiting neighboring stars. Schoolchildren can study the geography, oceans, and continents of...

When the stars are properly aligned, expect remarkable things. How useful, for example, to find that a planet we would like to know much more about -- HAT-P-7b, about 1000 light years from Earth -- is not only providing intriguing transit information right now, but is also in Kepler's field of view. We'd like to know whether there are massive outer planets in this system, or possibly a binary companion. These are questions that the Kepler observatory may be able to answer. Any transiting exoplanet is obviously of high interest, but HAT-P-7b stands out a bit more following the publication of two recent papers in separate journals. Both used the Subaru Telescope to examine the planet's unusual orbit, which appears to be retrograde or polar. This is useful stuff, because it's telling us something about how planetary systems form, offering useful evidence about planetary migration models. What we would expect is that planets that form in protoplanetary disks around young stars would have...

Friday is a travel day for me, so be aware that comment moderation will be slow and sporadic. I just have time to get in word about the upcoming launch of the WISE mission, slated for December 7. NASA is planning a media briefing next Tuesday (November 17) to discuss the mission, which is designed to scan the entire sky at infrared wavelengths, spotting perhaps hundreds of thousands of asteroids and studying a wide range of stars and galaxies. The technology is fascinating in and of itself. WISE will image the entire sky in the infrared, using detectors kept below 15 Kelvins (which is only 15 degrees C above absolute zero) by a solid hydrogen cryostat. The telescope will be oriented to look out at right angles to the Sun, always pointing away from the Earth, so that its observations sweep out a circle in the sky. After six months, the instrument will have observed the entire sky, producing nearly 1.5 million images and creating, ultimately, an atlas of the entire celestial sphere....

The exoplanet watch among our readers is clearly in full operation, to judge from the number of backchannel messages I received about the latest work from HARPS (High Accuracy Radial Velocity Planet Searcher). The remarkable ESO spectrograph attached to the La Silla 3.6-meter telescope now offers evidence that Sun-like stars that host planets will show a sparser lithium signature than stars without planets. Says Garik Israelian, lead author of the paper now appearing in Nature: "For almost ten years we have tried to find out what distinguishes stars with planetary systems from their barren cousins. We have now found that the amount of lithium in Sun-like stars depends on whether or not they have planets." All of this helps us understand our own star, whose low levels of lithium (140 times less than it should have had when formed) have long been apparent. The HARPS work draws on an analysis of some 500 stars, including seventy known to host planets. Ace planet hunter Michel Mayor...

It was a busy weekend for backchannel emails. I got off a Twitter post (OK, a 'tweet') on the centauri_dreams channel on Friday about the disturbing news from Kepler. The reaction was swift. The problem is caused by noisy amplifiers in the electronics of the space-borne telescope, which means the powers that be have to fiddle with the way data from Kepler is processed. This article in Nature News (thanks to all who forwarded links) spells it all out, saying that the planet hunt could be delayed. The article has circulated widely but apparently has problems of its own. William Borucki, Kepler principal investigator, posted this on Ian O'Neill's SpaceDisco site: "There is a mistake in the Nature article. The Kepler Mission is actually doing very well and is producing planet discoveries that will be announced early next year. Data from 3 of the 84 channels that have more noise than the others will be corrected or the data flagged to avoid being mixed in with the low noise data prior to...

While we've looked several times in these pages at David Kipping's work on exomoons, the investigation of moons much closer to home reminds us that finding a habitable satellite of another planet may not be out of our reach. After all, we're gaining insights into possible habitats for at least microbial life on (or in) places like Europa and Enceladus, and speculations about similar biospheres within some Kuiper Belt objects also keep them in contention. So what about a habitable moon around a distant gas giant? Kipping (University College London) has now gone to work on the question in relation to the Kepler space telescope. His findings are striking: A Saturn-sized planet in the habitable zone of an M-dwarf star would allow the detection of an exomoon down to 0.2 Earth masses. Image: A habitable exomoon would offer an exotic vista, a view that may be more common in the galaxy than we have previously imagined. Credit: Dan Durda. Now that sounds unusual, given that Kepler can't find...

We're making progress at detecting the signatures of organic chemicals on other planets. Mark Swain (JPL) and team have already made a name for themselves in this arena by their detection of carbon dioxide in the atmosphere of the 'hot Jupiter' HD 189733b, which followed earlier Hubble and Spitzer observations that revealed water vapor and methane there. Now they've used the same observatories to study another hot gas giant, HD 209458b, which orbits a star 150 light years away in Pegasus. The result: A detection of basic materials necessary for life. Swain spells out what the team found and its significance: "[HD 209458b is] the second planet outside our solar system in which water, methane and carbon dioxide have been found, which are potentially important for biological processes in habitable planets. Detecting organic compounds in two exoplanets now raises the possibility that it will become commonplace to find planets with molecules that may be tied to life." No one is suggesting...

After we've found an Earth-like planet with a potential for life, what further things can we do to investigate it? A team led by Jean Schneider (Paris Observatory) asks this question in a new paper, speculating that there are things a technological society does that leave a sure trace. Given the right instruments (no small requirement), we might look, for example, for Carbon Fluoro Compounds (CFCs). Well known for their damaging effects on our ozone layer, CFCs absorb infrared light at characteristic wavelengths, making their signature a revealing one. Spotting an Extraterrestrial 'Techno-Signature' Schneider calls markers like this 'techno-signatures' (as opposed to the more familiar 'bio-signatures'). They're spectral features that can't be explained by complex organic chemistry. Find CFCs in the atmosphere of a distant world and you've got a snapshot of technological chemical synthesis at work. We might speculate as to whether the average civilization produces CFCs in abundance,...