A Comprehensive Characterization of the 70 Virginis Planetary System

TL;DR

This paper provides a detailed characterization of the 70 Virginis exoplanetary system, including host star properties, refined orbital parameters, and transit constraints, using a combination of photometry, spectroscopy, and interferometry.

Contribution

It offers the first comprehensive analysis of the system combining multiple observational techniques and refines the orbital and physical parameters of the host star and planet.

Findings

Host star radius measured with 1.5% uncertainty

Refined orbital solution for the planet

Transit ruled out at 5σ level for a Jupiter-sized planet

Abstract

An on-going effort in the characterization of exoplanetary systems is the accurate determination of host star properties. This effort extends to the relatively bright host stars of planets discovered with the radial velocity method. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) is aiding in these efforts as part of its observational campaign for exoplanet host stars. One of the first known systems is that of 70 Virginis, which harbors a jovian planet in an eccentric orbit. Here we present a complete characterization of this system with a compilation of TERMS photometry, spectroscopy, and interferometry. We provide fundamental properties of the host star through direct interferometric measurements of the radius (1.5\% uncertainty) and through spectroscopic analysis. We combined 59 new Keck HIRES radial velocity measurements with the 169 previously published from the ELODIE, Hamilton, and HIRES spectrographs, to calculate a refined orbital solution and construct a transit ephemeris for the planet. These newly determined system characteristics are used to describe the Habitable Zone of the system with a discussion of possible additional planets and related stability simulations. Finally, we present 19 years of precision robotic photometry that constrain stellar activity and rule out central planetary transits for a Jupiter-radius planet at the 5$\sigma$ level, with reduced significance down to an impact parameter of $b = 0.95$.