The European Space Agency has just announced the official adoption of the PLATO mission. The untangled acronym -- PLAnetary Transits and Oscillations of stars -- tells us that, like Kepler and CoRoT, this is a planet hunting mission with asteroseismological implications. Photometric monitoring of nearby bright stars for planetary transits and determination of planetary radii should help build our target list for spectroscopic follow-up as we delve into planetary atmospheres looking for biosignatures. Launch is scheduled for 2026. Asteroseismology studies how stars oscillate, giving us information about the internal structure of the star that would not be available through properties like brightness and surface temperature. PLATO will be carrying out high precision photometric monitoring at visible wavelengths, targeting bright stars (mV ? 11), though with capabilities for fainter stars down to magnitude 16. Several hundred thousand stars will ultimately be characterized in the search...

As announced yesterday at NASA Ames, the Kepler team has released the final Kepler catalog from the spacecraft’s first four years of data and its deep stare into Cygnus. The numbers still impress me despite our having watched them grow with each new report: We have 4034 planet candidates, of which 2335 have been verified as exoplanets. More than 30 of the approximately 50 near-Earth sized habitable zone candidates have been verified. The new release brought us 219 new candidates, 10 of them habitable zone possibilities, giving us a final catalog that is our first take on the prevalence and characteristics of planets in the Milky Way, and paving the way for future space-based instruments as we look for targets for atmospheric characterization and direct imaging. By introducing simulated planet transit signals and adding known false signals, the researchers were able to tighten up the catalog, ensuring against errors in the analysis growing out of the team’s processing methods. The...

The Pale Red Dot campaign that discovered Proxima Centauri b produced one of the great results of exoplanet detection. For many of us, the idea that a world of roughly Earth mass might be orbiting in Proxima Centauri's habitable zone -- where liquid water can exist on the surface -- was almost too good to be true, and it highlighted the real prospect that if we find such a planet around the closest star to our own, there must be many more around similar stars. Hence the importance of learning more about our closest neighbors. Which is why it's so heartening to see that Pale Red Dot is by no means done. This morning, the team led by Guillem Anglada-Escudé (Queen Mary University, London) announced plans to acquire data from the European Southern Observatory's HARPS instrument (High Accuracy Radial velocity Planet Searcher) in a new campaign to study not just Proxima Centauri in search of further planets, but also the red dwarfs Barnard's Star and Ross 154. Also involved will be...

Small stars are fascinating because of their sheer ubiquity. Some estimates for the fraction of red dwarfs in the galaxy go as high as 80 percent, meaning the planets around such stars are going to be the most common venues for possible life. For a time, I thought brown dwarfs would be shown to be even more numerous, but the WISE [Wide-field Infrared Survey Explorer] data have indicated otherwise (see Brown Dwarfs Sparser than Expected). Hopes for a brown dwarf closer than the Alpha Centauri stars (and thus a convenient intermediary destination for future probes) have dwindled down to nothing, but we do have interesting systems like Luhman 16 AB, the third closest system to the Sun, captured in the image below via a 'stack' of twelve images courtesy of the Hubble instrument. The work is from Luigi Bedin (INAF-Osservatorio Astronomico di Padova, Italy) and team, helping us with orbital parameters of the pair and demonstrating that there is no third companion. Image: Luhman 16 AB as...

Just how did the seven planets around TRAPPIST-1 form? This is a system with seven worlds each more or less the size of the Earth orbiting a small red dwarf. If these planets formed in situ, an unusually dense disk would have been required, making planet migration the more likely model. But if the planets migrated from beyond the snowline, how do we explain their predominantly rocky composition? And what mechanisms are at work in this system to produce seven planets all of approximately the same size? New work out of the University of Amsterdam attempts to resolve the question through a different take on planet formation, one that involves the migration not of planets but planetary building blocks in the form of millimeter to centimeter-sized particles. Chris Ormel (University of Amsterdam) and team note that thermal emission from pebbles like these has been observed around other low-mass stars and even brown dwarfs. The researchers believe these migrating particles become planetary...

I seem to be reminded every day of how many discoveries are lurking in our archives. On the question of red dwarf stars and the flare activity that could compromise the habitability of planets around them, the ten year dataset from GALEX is proving invaluable. The Galaxy Explorer Evolution spacecraft was launched in 2003 and operated until 2012. Bear in mind that it was designed to study the evolution of galaxies at ultraviolet wavelengths. But now this valuable mission's archives are helping us track the study of nearby habitable planets. Led by first author Chase Million (Million Concepts, State College PA), a project dubbed gPhoton has set about reprocessing more than 100 terabytes of GALEX data now at the Mikulski Archive for Space Telescopes (MAST), which is maintained at the Space Telescope Science Institute in Baltimore. Million worked with STScI's Clara Brasseur to develop custom software that could tease out the signature of flares for several hundred red dwarf stars. Dozens...