MASSIVE: A Bayesian analysis of giant planet populations around low-mass stars

Abstract

Direct imaging has led to the discovery of several giant planet and brown dwarf companions. These imaged companions populate a mass, separation and age domain (mass>1MJup, orbits>5AU, age<1Gyr) quite distinct from the one occupied by exoplanets discovered by the radial velocity or transit methods. This distinction could pinpoint that different formation mechanisms are at play. We aim at investigating correlations between the host star's mass and the presence of wide-orbit giant planets, and at providing new observational constraints on planetary formation models. We observed 58 young and nearby M-type dwarfs in L'-band with the VLT/NaCo instrument and used ADI algorithms to optimize the sensitivity to planetary-mass companions and to derive the best detection limits. We estimate the probability of detecting a planet as a function of its mass and physical separation around each target. We conduct a Bayesian analysis to determine the frequency of substellar companions orbiting low-mass stars, using a homogenous sub-sample of 54 stars. We derive a frequency of $4.4_{-1.3}^{+3.2}\%$ for companions with masses in the range of 2-80MJup}, and $2.3_{-0.7}^{+2.9}$\% for planetary mass companions (2-14MJup), at physical separations of 8 to 400AU for both cases. Comparing our results with a previous survey targeting more massive stars, we find evidence that substellar companions more massive than 1MJup with a low mass ratio Q with respect to their host star (Q<1%), are less frequent around low-mass stars. This may represent an observational evidence that the frequency of imaged wide-orbit substellar companions is correlated with stellar mass, corroborating theoretical expectations. On the opposite, we show statistical evidence that intermediate-mass ratio (1%<Q<5%) companion with masses >2MJup might be independent from the mass of the host star.

Accepted for publication on A&A, 23 pages, 10 figures, 13 tables

References in corpus (18)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• One or more bound planets per Milky Way star from microlensing observations
• On the age of the $\beta$ Pictoris moving group
• Planets Around Low-Mass Stars (PALMS). IV. The Outer Architecture of M Dwarf Planetary Systems
• A Stellar Census of the Tucana-Horologium Moving Group
• Discovery of a young planetary mass companion to the nearby M dwarf VHS J125601.92-125723.9
• A novel L-band imaging search for giant planets in the Tucana and Beta Pictoris moving groups
• BANYAN. IV. Fundamental parameters of low-mass star candidates in nearby young stellar kinematic groups - Isochronal Age determination using Magnetic evolutionary models
• Young Nearby Loose Associations
• Discovery of a wide planetary-mass companion to the young M3 star GU Psc
• Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys, II: The Frequency of Planets Orbiting M Dwarfs
• Discovery of a Young Substellar Companion in Chamaeleon
• BANYAN. V. A Systematic All-Sky Survey for New Very Late-Type Low-Mass Stars and Brown Dwarfs in Nearby Young Moving Groups
• Reconnaissance of the HR 8799 Exosolar System II: Astrometry and Orbital Motion
• New Evidence for a Substellar Luminosity Problem: Dynamical Mass for the Brown Dwarf Binary Gl 417BC
• Discovery of 9 New Companions to Nearby Young M Stars with the Altair AO System
• Physical and orbital properties of Beta Pictoris b
• The Coolest Isolated Brown Dwarf Candidate Member of TWA

Cited by in corpus (23)

• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• The newborn planet population emerging from ring-like structures in discs
• Characterization of exoplanets from their formation III: The statistics of planetary luminosities
• The SPHERE infrared survey for exoplanets (SHINE) -- II. Observations, Data reduction and analysis Detection performances and early-results
• Planet formation around M dwarfs via disc instability: Fragmentation conditions and protoplanet properties
• BEAST begins: Sample characteristics and survey performance of the B-star Exoplanet Abundance Study
• Searching for Giant Exoplanets around M-dwarf Stars (GEMS) I: Survey Motivation
• Fragmentation favoured in discs around higher mass stars
• PSYM-WIDE: a survey for large-separation planetary-mass companions to late spectral type members of young moving groups
• Large Adaptive Optics Survey for Substellar Objects (LASSO) Around Young, Nearby, Low-mass Stars with Robo-AO
• Radial-velocity jitter of stars as a function of observational timescale and stellar age
• Direct imaging of exoplanets: Legacy and prospects
• The COBREX archival survey: improved constraints on the occurrence rate of wide-orbit substellar companions. I. A uniform re-analysis of 400 stars from the GPIES survey
• The Feasibility of Directly Imaging Nearby Cold Jovian Planets with MIRI/JWST
• The Scorpion Planet Survey: Wide-Orbit Giant Planets Around Young A-type Stars
• BANYAN. X. Discovery of a wide, low-gravity L-type companion to a fast-rotating M3 dwarf
• A low-mass companion desert among intermediate-mass visual binaries: The scaled-up counterpart to the brown dwarf desert
• Giant planets population around B stars from the first part of the BEAST survey
• On the survivability of a population of gas giant planets on wide orbits
• An optimised survey strategy for the ERIS/NIX imager: searching for young giant exoplanets and very low mass brown dwarfs using the K-peak custom photometric filter
• VLT/SPHERE survey for exoplanets around young, early-type stars including systems with multi-belt architectures
• GTC/CanariCam deep mid-infrared imaging survey of northern stars within 5 pc
• Occurrence rates of accreting companions from a new method for computing emission-line survey sensitivity: application to the H-alpha Giant Accreting Protoplanet Survey