The high albedo of the hot Jupiter Kepler-7b

Details The high albedo of the hot Jupiter Kepler-7b The high albedo of the hot Jupiter Kepler-7b

2011-05-25

arxiv.org/abs/1105.5143v1

Astronomy and Astrophysics

Astrophysics

Earth and Planetary Astrophysics

Accepted for publication in ApJL

Scientific paper

Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric precision at visible wavelengths to investigate these expectations. The NASA Kepler mission provides a means to widen the sample and to assess the extent to which hot Jupiter albedos are low. We present a global analysis of Kepler-7b based on Q0-Q4 data, published radial velocities, and asteroseismology constraints. We measure an occultation depth in the Kepler bandpass of 44+-5 ppm. If directly related to the albedo, this translates to a Kepler geometric albedo of 0.32+-0.03, the most precise value measured so far for an exoplanet. We also characterize the planetary orbital phase lightcurve with an amplitude of 42+-4 ppm. Using atmospheric models, we find it unlikely that the high albedo is due to a dominant thermal component and propose two solutions to explain the observed planetary flux. Firstly, we interpret the Kepler-7b albedo as resulting from an excess reflection over what can be explained solely by Rayleigh scattering, along with a nominal thermal component. This excess reflection might indicate the presence of a cloud or haze layer in the atmosphere, motivating new modeling and observational efforts. Alternatively, the albedo can be explained by Rayleigh scattering alone if Na and K are depleted in the atmosphere by a factor of 10-100 below solar abundances.

Affiliated with

Also associated with

No associations

Rating

The high albedo of the hot Jupiter Kepler-7b does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The high albedo of the hot Jupiter Kepler-7b, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The high albedo of the hot Jupiter Kepler-7b will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-216541