Volume 545, September 2012
|Number of page(s)||4|
|Published online||04 September 2012|
Evidence for the disintegration of KIC 12557548 b
1 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
2 SRON, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
3 Astronomical Institute Anton Pannekoek, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam, The Netherlands
Received: 6 June 2012
Accepted: 14 August 2012
Context. The Kepler object KIC 12557548 b is peculiar. It exhibits transit-like features every 15.7 h that vary in depth between 0.2% and 1.2%. Rappaport et al. (2012, ApJ, 752, 1) explain the observations in terms of a disintegrating, rocky planet that has a trailing cloud of dust created and constantly replenished by thermal surface erosion. The variability of the transit depth is then a consequence of changes in the cloud optical depth.
Aims. We aim to validate the disintegrating-planet scenario by modeling the detailed shape of the observed light curve, and thereby constrain the cloud particle properties to better understand the nature of this intriguing object.
Methods. We analyzed the six publicly-available quarters of raw Kepler data, phase-folded the light curve and fitted it to a model for the trailing dust cloud. Constraints on the particle properties were investigated with a light-scattering code.
Results. The light curve exhibits clear signatures of light scattering and absorption by dust, including a brightening in flux just before ingress correlated with the transit depth and explained by forward scattering, and an asymmetry in the transit light curve shape, which is easily reproduced by an exponentially decaying distribution of optically thin dust, with a typical grain size of 0.1 μm.
Conclusions. Our quantitative analysis supports the hypothesis that the transit signal of KIC 12557548 b is due to a variable cloud of dust, most likely originating from a disintegrating object.
Key words: eclipses / occultations / planet-star interactions / planets and satellites: general
© ESO, 2012
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.