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,...