NASA | JPL-Caltech | Spitzer | Kepler | 2014 July 23
Thanks to NASA's Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement ever of the radius of a planet outside our solar system. The size of the exoplanet, dubbed Kepler-93b, is now known to an uncertainty of just 74 miles (119 kilometers) on either side of the planetary body.
The findings confirm Kepler-93b as a "super-Earth" that is about one-and-a-half times the size of our planet. Although super-Earths are common in the galaxy, none exist in our solar system. Exoplanets like Kepler-93b are therefore our only laboratories to study this major class of planet.
With good limits on the sizes and masses of super-Earths, scientists can finally start to theorize about what makes up these weird worlds. Previous measurements, by the Keck Observatory in Hawaii, had put Kepler-93b's mass at about 3.8 times that of Earth. The density of Kepler-93b, derived from its mass and newly obtained radius, indicates the planet is in fact very likely made of iron and rock, like Earth. ...
Kepler-93b: A Terrestrial World Measured to within 120 km,
and a Test Case for a New Spitzer Observing Mode - Sarah Ballard et al
- Astrophysical Journal 790(1) 12 (2014 July 20) DOI: 10.1088/0004-637X/790/1/12
arXiv.org > astro-ph > arXiv:1405.3659 > 14 May 2014