Characterization of Kepler-91b and the Investigation of a Potential Trojan Companion Using EXONEST
Abstract
Presented here is an independent re-analysis of the Kepler light curve of Kepler-91 (KIC 8219268). Using the EXONEST software package, which provides both Bayesian parameter estimation and Bayesian model testing, we were able to re-confirm the planetary nature of Kepler-91b. In addition to the primary and secondary eclipses of Kepler-91b, a third dimming event appears to occur approximately 60o away (in phase) from the secondary eclipse, leading to the hypothesis that a Trojan planet may be located at the L4 or L5 Lagrange points. Here, we present a comprehensive investigation of four possibilities to explain the observed dimming event using all available photometric data from the Kepler Space Telescope, recently obtained radial velocity measurements, and N-body simulations. We find that the photometric model describing Kepler-91b and a Trojan planet is highly favored over the model involving Kepler-91b alone. However, it predicts an unphysically high temperature for the Trojan companion, leading to the conclusion that the extra dimming event is likely a false-postive.
- Publication:
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The Astrophysical Journal
- Pub Date:
- December 2015
- DOI:
- 10.1088/0004-637X/814/2/147
- arXiv:
- arXiv:1511.01068
- Bibcode:
- 2015ApJ...814..147P
- Keywords:
-
- methods: data analysis;
- planets and satellites: detection;
- planets and satellites: fundamental parameters;
- techniques: photometric;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- Accepted at The Astrophysical Journal