A Uniform Analysis of 118 Stars with High-Contrast Imaging: Long Period Extrasolar Giant Planets are Rare around Sun-like Stars

TL;DR

This study combines multiple high-contrast imaging surveys to constrain the population and distribution of long-period giant exoplanets around Sun-like stars, finding such planets are rare beyond certain distances.

Contribution

It provides a uniform analysis of 118 stars using various models and stellar mass corrections, refining the limits on the presence of distant giant planets compared to previous studies.

Findings

Giant planets beyond 65 AU are unlikely around Sun-like stars with 95% confidence.

Applying stellar mass corrections extends the possible planet distance limits.

Different planet luminosity models significantly affect the estimated upper limits.

Abstract

We expand on the results of Nielsen et al. (2008), using the null result for giant extrasolar planets around the 118 target stars from the VLT NACO H and Ks band planet search (Masciadri et al. 2005), the VLT and MMT Simultaneous Differential Imaging (SDI) survey (Biller et al. 2007), and the Gemini Deep Planet Survey (Lafreniere et al. 2007) to set constraints on the population of giant extrasolar planets. Our analysis is extended to include the planet luminosity models of Fortney et al. (2008), as well as the correlation between stellar mass and frequency of giant planets found by Johnson et al. (2007). Doubling the sample size of FGKM stars strengthens our conclusions: a model for extrasolar giant planets with power-laws for mass and semi-major axis as giving by Cumming et al. (2008) cannot, with 95% confidence, have planets beyond 65 AU, compared to the value of 94 AU reported in Nielsen et al. (2008), using the models of Baraffe et al. (2003). When the Johnson et al. (2007) correction for stellar mass (which gives fewer Jupiter-mass companions to M stars with respect to solar-type stars) is applied, however, this limit moves out to 82 AU. For the relatively new Fortney et al. (2008) models, which predict fainter planets across most of parameter space, these upper limits, with and without a correction for stellar mass, are 182 and 234 AU, respectively.