Constrains on planets around beta Pic with Harps radial velocity data

TL;DR

This study uses 8 years of HARPS radial velocity data to constrain the mass of Beta Pictoris b and search for additional planets, providing the first direct mass limit for an imaged exoplanet and excluding certain hot Jupiters.

Contribution

First direct radial velocity constraints on Beta Pictoris b's mass and limits on additional close-in giant planets around a young, early-type star.

Findings

Beta Pic b's mass is less than 10-25 MJup depending on orbit distance.

No hot Jupiters with periods less than 100 days and mass over 2.5 MJup detected.

Detection limits exclude planets more massive than 9 MJup in 100-500 day period range.

Abstract

Context. The {\beta} Pictoris system with its debris disk and a massive giant planet orbiting at \simeq 9 AU represents an ideal laboratory to study giant planet formation and evolution as well as planet-disk interactions. {\beta} Pic b can also help testing brightness-mass relations at young ages. Other planets, yet undetected, may of course be present in the system. Aims. We aim at putting direct constrains on the mass of {\beta} Pic b and at searching for additional jovian planets on orbits closer than typically 2 AU. Methods. We use high precision Harps data collected over 8 years since 2003 to measure and analyse {\beta} Pic radial velocities. Results. We show that the true mass of {\beta} Pic b is less than 10, 12, 15.5, 20 and 25 MJup if orbiting respectively at 8, 9, 10, 11 and 12 AU. This is the first direct constraint on the mass of an imaged planet. The upper mass found is well in the range predicted by brightness-mass relations provided by current "hot start" models. We also exclude the presence of giant planets more massive than 2.5 MJup with periods less than 100 days (hot Jupiters), more massive than 9 MJup for periods in the range 100-500 days. In the 500-1000 day range, the detection limit is in the brown dwarf domain. Beyond the intrinsic interest for {\beta} Pic, these results show the possibilities of precise RV measurements of early type, rapidly rotating stars.