kepler-11fとは 意味・読み方・使い方

Kepler-11f is an exoplanet (extrasolar planet) discovered in the orbit of the sunlike star Kepler-11 by NASA's Kepler spacecraft, which searches for planets that transit (cross in front of) their host stars. Kepler-11f is the sixth planet from its star, orbiting one fourth of the distance (.25 AU) of the Earth from the Sun every 47 days. It is the furthest of the first five planets in the system, as compared to the outlying Kepler-11g. Kepler-11f is the least massive of Kepler-11's six planets, at nearly twice the mass of Earth; it is about 2.6 times the radius of Earth. Along with planets d and e and unlike the two inner planets in the system, Kepler-11f has a density lower than that of water and comparable to that of Saturn. This suggests that Kepler-11f has a significant hydrogen–helium atmosphere. According to NASA, Kepler-11f and its sister planets form the most compact system yet discovered. The Kepler-11 planets constitute the first system discovered with more than three transiting planets. Kepler-11f was announced to the public on February 2, 2011 after follow-up investigations at several observatories.