Kepler 21b: Super Earth-size Planet
Confirmed Around Bright F6 Subgiant Star
A research team led by Steve Howell, NASA Ames Research Center, has announced the discovery of an exoplanet orbiting one of the brightest stars in the Kepler field of view.
Named Kepler-21b, the planet is approximately 1.6 times the radius of Earth and nearly ten times the mass of Earth. Circling its host star every 2.8 days, Kepler-21b orbits at a distance of six million km – nearly ten times closer than Mercury orbits the sun. The surface temperature is calculated to be 2,960 Fahrenheit. While this temperature is nowhere near the habitable zone in which liquid water might be found, the planet’s size is approaching that of Earth.
The parent star, HD 179070, a little hotter and brighter than the sun, is 352 light years away. Somewhat similar to the sun, the parent star has a mass of 1.3 solar masses, is larger at 1.9 solar radii, and its age is 2.84 billion years- younger than the sun’s 4.6 billion years. Although Kepler-21b is pretty small and very far away, unable to be seen with the naked eye, the parent star can easily be seen with binoculars or a small telescope.
Where to look for:
This incredibly sensitive and difficult detection required the collaboration of over 65 astronomers with both space and multiple ground-based telescopes to confirm the newest member of the Kepler family.