January 7, 2014
Kepler Astronomers Find Five New Rocky Planets
Lee Rannals for redOrbit.com - Your Universe Online
According to the latest findings, Kepler-99b and Kepler-406b are 40 percent larger in size than Earth and have a density similar to lead. NASA said the planets orbit their host stars in less than five and three days respectively, which means these planets are too hot for life to exist.
As part of their study, the astronomers measured the reflex wobble of the host star, which is caused by gravity from the orbiting planet tugging on the star. This measurement helps reveal the mass of the planet because the more the star wobbles, the more massive the planet.
"This marvelous avalanche of information about the mini-Neptune planets is telling us about their core-envelope structure, not unlike a peach with its pit and fruit," stated Geoff Marcy, professor of astronomy at University of California, Berkeley who led the summary analysis of the high-precision Doppler study. "We now face daunting questions about how these enigmas formed and why our solar system is devoid of the most populous residents in the galaxy."
The scientists were able to confirm 41 exoplanets discovered by Kepler as well as determine the masses of 16 by using the W. M. Keck Observatory in Hawaii, which features one of the world’s largest ground-based telescopes. The team was also able to determine the density of the planets and characterize them as rocky or gaseous.
"Kepler's primary objective is to determine the prevalence of planets of varying sizes and orbits. Of particular interest to the search for life is the prevalence of Earth-sized planets in the habitable zone," said Natalie Batalha, Kepler mission scientist at NASA’s Ames Research Center at Moffett Field, California. "But the question in the back of our minds is: are all planets the size of Earth rocky? Might some be scaled-down versions of icy Neptunes or steamy water worlds? What fraction are recognizable as kin of our rocky, terrestrial globe?"
The team wrote in the Astrophysical Journal that they were able to validate 38 new planets, six of which are non-transiting planets only seen in Doppler data.
Image 2 (below): Chart of Kepler planet candidates as of January 2014. Credit: NASA Ames