Stellar Variability of the Exoplanet Hosting Star HD 63454

TL;DR

This study re-analyzes radial velocity data and photometric observations of HD 63454, a young active star with a close-in Jovian exoplanet, to refine its transit ephemeris and investigate stellar activity and star-planet interactions.

Contribution

It provides an updated transit ephemeris for HD 63454 and rules out photometric signatures of star-planet interactions and transits, improving understanding of the system's properties.

Findings

No photometric transit signatures detected.

Star remains photometrically stable at 3 millimag level.

Constraints placed on the planet's orbital and physical properties.

Abstract

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.