* Astronomy

Title: Stellar Variability of the Exoplanet Hosting Star HD 63454
Authors: Stephen R. Kane, Diana Dragomir, David R. Ciardi, Jae-Woo Lee, Gaspare Lo Curto, Christophe Lovis, Dominique Naef, Suvrath Mahadevan, Genady Pilyavsky, Stephane Udry, Xuesong Wang, Jason Wright

Of the hundreds of exoplanets discovered using the radial velocity technique, many are orbiting close to their host stars with periods less than 10 days. One of these, HD 63454, is a young active K dwarf which hosts a Jovian planet in a 2.82 day period orbit. The planet has a 14% transit probability and a predicted transit depth of 1.2%. Here we provide a re-analysis of the radial velocity data to produce an accurate transit ephemeris. We further analyse 8 nights of time series data to search for stellar activity both intrinsic to the star and induced by possible interactions of the exoplanet with the stellar magnetospheres. We establish the photometric stability of the star at the 3 millimag level despite strong Ca II emission in the spectrum. Finally, we rule out photometric signatures of both star-planet magnetosphere interactions and planetary transit signatures. From this we are able to place constraints on both the orbital and physical properties of the planet.

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HD 63454 is a ninth magnitude K-type main sequence star located approximately 117 light-years away in the constellation of Chamaeleon. It is somewhat cooler and less luminous than our Sun.
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