The young planetary system K2-25: constraints on companions and starspots
Abstract
The abundance of planets with orbital periods of a few to tens of days suggests that exoplanets experience complex dynamical histories. Planets in young stellar clusters or associations have well-constrained ages and therefore provide an opportunity to explore the dynamical evolution of exoplanets. K2-25b is a Neptune-sized planet in an eccentric 3.48 day orbit about an M4.5 dwarf star in the Hyades cluster (650 Myr) and is the most accessible transiting planet in a cluster to date. In order to investigate its non-zero eccentricity and tight orbit, we analyze transit timing variations (TTVs) which may reveal clues to the migration processes that may have acted on the planet. We obtained 21 non-consecutive nights of photometric data from the MEarth and Spitzer telescopes, and additionally analyze long-cadence data from K2. Each transit lightcurve is fit individually to investigate whether inhomogeneities on the stellar surface (such as spots or plages) are differentially affecting our transit observations. The measured transit depth and duration do not vary significantly between transits, indicating that the features on the stellar surface are not changing at a level detectable in our data. We then looked for TTVs as evidence of a long-period or non-transiting perturber in the system, but find no evidence for companions. The MEarth team is grateful for support from the David and Lucile Packard Fellowship for Science and Engineering, the John Templeton Foundation (awarded to D.C.), and the National Science Foundation, and NASA. ERN acknowledges support from the NSF through the GRF and the AAPF programs (award AST-1602597).
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23324734K