Kepler-7b: A Transiting Planet with Unusually Low Density

TL;DR

This paper reports the discovery of Kepler-7b, a transiting exoplanet with an exceptionally low density, larger radius, and lower mass than Jupiter, orbiting a star similar to the Sun but more massive and larger.

Contribution

The paper presents the first detailed characterization of Kepler-7b, highlighting its unusually low density and large radius compared to prior known exoplanets.

Findings

Kepler-7b has a density of 0.17 g/cc, the second lowest for an exoplanet.

Kepler-7b's radius is 1.48 times that of Jupiter.

The planet's orbital period is 4.886 days.

Abstract

We report the discovery and confirmation of Kepler-7b, a transiting planet with unusually low density. The mass is less than half that of Jupiter, Mp = 0.43 Mj, but the radius is fifty percent larger, Rp = 1.48 Rj. The resulting density, 0.17 g/cc, is the second lowest reported so far for an extrasolar planet. The orbital period is fairly long, P = 4.886 days, and the host star is not much hotter than the Sun, Teff = 6000 K. However, it is more massive and considerably larger than the sun, Mstar = 1.35 Msun and Rstar = 1.84 Rsun, and must be near the end of its life on the Main Sequence.