SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets Around Young Stars

TL;DR

This paper reviews precursor observations for the SIM PlanetQuest project aimed at detecting gas giant planets around young stars, focusing on eliminating sources of astrometric noise through various observational methods.

Contribution

It provides a comprehensive assessment of target star suitability based on photometry, imaging, interferometry, and radial velocities, identifying key factors affecting astrometric planet detection.

Findings

No close companions found in high contrast imaging surveys.

Many target stars are fast rotators or variable, affecting astrometric precision.

Photometric variability is the main factor reducing target viability.

Abstract

We present a review of precursor observing programs for the SIM PlanetQuest Key project devoted to detecting Jupiter mass planets around young stars. In order to ensure that the stars in the sample are free of various sources of astrometric noise that might impede the detection of planets, we have initiated programs to collect photometry, high contrast images, interferometric data and radial velocities for stars in both the Northern and Southern hemispheres. We have completed a high contrast imaging survey of target stars in Taurus and the Pleiades and found no definitive common proper motion companions within one arcsecond (140 AU) of the SIM targets. Our radial velocity surveys have shown that many of the target stars in Sco-Cen are fast rotators and a few stars in Taurus and the Pleiades may have sub-stellar companions. Interferometric data of a few stars in Taurus show no signs of stellar or sub-stellar companions with separations of <5 mas. The photometric survey suggests that approximately half of the stars initially selected for this program are variable to a degree (1 sigma>0.1 mag) that would degrade the astrometric accuracy achievable for that star. While the precursor programs are still a work in progress, we provide a comprehensive list of all targets ranked according to their viability as a result of the observations taken to date. By far, the observable that moves the most targets from the SIM-YSO program is photometric variability.