Host Star Properties and Transit Exclusion for the HD 38529 Planetary System

TL;DR

This study refines the properties and orbital parameters of the HD 38529 planetary system, confirming the non-transiting nature of the inner planet and analyzing stellar brightness variations.

Contribution

It provides new stellar and orbital measurements for HD 38529, improves the planetary orbit solutions, and rules out a previously suggested third planet.

Findings

Inner planet does not transit

No evidence for third planet

Star exhibits cyclic brightness variations

Abstract

The transit signature of exoplanets provides an avenue through which characterization of exoplanetary properties may be undertaken, such as studies of mean density, structure, and atmospheric composition. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) is a program to expand the catalog of transiting planets around bright host stars by refining the orbits of known planets discovered with the radial velocity technique. Here we present results for the HD 38529 system. We determine fundamental properties of the host star through direct interferometric measurements of the radius and through spectroscopic analysis. We provide new radial velocity measurements that are used to improve the Keplerian solution for the two known planets, and we find no evidence for a previously postulated third planet. We also present 12 years of precision robotic photometry of HD 38529 that demonstrate the inner planet does not transit and the host star exhibits cyclic variations in seasonal mean brightness with a timescale of approximately six years.