Three Tiny Exoplanets Suggest Solar System Not So Special

ananyo writes "Adding to its already long roster of firsts, NASA's Kepler spacecraft has found the three smallest extrasolar planets ever detected — all of them smaller than Earth, and the most diminutive no larger than Mars. The newly discovered trio forms a miniature planetary system orbiting a cool, dim red dwarf star called KOI-961. Because they are so close to their star, the three exoplanets are too hot to support life. But unlike most previously known exoplanets, the vast majority of which are Jupiter-scale gas giants, all three are thought to be rocky worlds like Earth and the other worlds of the inner Solar System."

Re:A flicker of light.

[itchythebear]

Yes, that star's habitable zone is probably closer than our Sun's, but the planets are still way to close to be considered in that star's habitable zone.

FTFA:

At the AAS meeting, the discovery team announced that all three planets orbiting KOI-961 whip around the star in less than two days. The outermost body is the tiniest, with a diameter half that of Earth, or about the same as Mars, and a temperature of about 400 degrees Celsius. The inner two planets are larger, with diameters about three-fourths that of Earth. But that is still smaller than Venus. Because the planets are all small and close to their star, much of the atmosphere they may once have had would have evaporated, leaving behind bare rock, Marcy says.

Re:Orbital Period and Detection

[thrich81]

Kepler detects planets by seeing periodic small drops in the brightness of the host star as the planet passes in front of it. That is only going to work for planets with a pretty short orbital period (I don't know the limit) since they depend on multiple observations to get the orbital characteristics. Neptune with is 100+ year period would not be measurable and unlikely to be observed even once during the mission.