Michele Johnson, Ames Research Center Astronomers have
discovered a pair of neighboring planets with dissimilar
densities orbiting very close to each other. The planets are too
close to their star to be in the so-called "habitable zone," the
region in a system where liquid water might exist on the
surface, but they have the closest-spaced orbits ever confirmed.
The findings are published today in the journal Science. The
research team, led by Josh Carter, a Hubble fellow at the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.,
and Eric Agol, a professor of astronomy at the University of
Washington in Seattle, used data from NASA's Kepler space
telescope, which measures dips in the brightness of more than
150,000 stars, to search for transiting planets. The inner
planet, Kepler-36b, orbits its host star every 13.8 days and the
outer planet, Kepler-36c, every 16.2 days. On their closest
approach, the neighboring duo comes within about 1.2 million
miles of each other. This is only five times the E