On the survivability of a population of gas giant planets on wide orbits

Abstract

The existence of giant planets on wide orbits ($\stackrel{>}{{}_{\sim }}100$AU) challenge planet formation theories; the core accretion scenario has difficulty in forming them, whereas the disc instability model forms an overabundance of them that is not seen observations. We perform $N$-body simulations investigating the effect of close stellar encounters ($\le 1200$AU) on systems hosting wide-orbit giant planets and the extent at which such interactions may disrupt the initial wide-orbit planet population. We find that the effect of an interaction on the orbit of a planet is stronger for high-mass, low-velocity perturbers, as expected. We find that due to just a single encounter there is a $\sim 17$ chance that the wide-orbit giant planet is liberated in the field, a $\sim 10$% chance it is scattered significantly outwards, and a $\sim 6$% chance it is significantly scattered inwards. Moreover, there is a $\sim 21\%$ chance that its eccentricity is excited to e>0.1, making it more prone to disruption in subsequent encounters. The results strongly suggest that the effect of even a single stellar encounter is significant in disrupting the primordial wide-orbit giant planet population; in reality the effect will be even more prominent, as in a young star-forming region more such interactions are expected to occur. We conclude that the low occurrence rate of wide-orbit planets revealed by observational surveys does not exclude the possibility that such planetary systems are initially abundant, and therefore the disc-instability model may be a plausible scenario for their formation.

10 pages, 9 figures

References in corpus (31)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• The Two Modes of Gas Giant Planet Formation
• A Spitzer view of protoplanetary disks in the gamma Velorum cluster
• The SPHERE infrared survey for exoplanets (SHINE). III. The demographics of young giant exoplanets below 300 au with SPHERE
• Planets Around Low-Mass Stars (PALMS). IV. The Outer Architecture of M Dwarf Planetary Systems
• Discovery of a warm, dusty giant planet around HIP65426
• Brown dwarf formation by gravitational fragmentation of massive, extended protostellar discs
• A Statistical Analysis of SEEDS and Other High-Contrast Exoplanet Surveys: Massive Planets or Low-Mass Brown Dwarfs?
• Kinematic Structure of the Orion Nebula Cluster and its Surroundings
• A giant exoplanet orbiting a very low-mass star challenges planet formation models
• The International Deep Planet Survey II: The frequency of directly imaged giant exoplanets with stellar mass
• A rich population of free-floating planets in the Upper Scorpius young stellar association
• Internal dynamics and membership of the NGC 3603 Young Cluster from microarcsecond astrometry
• The Young Suns Exoplanet Survey: Detection of a wide orbit planetary mass companion to a solar-type Sco-Cen member
• Close encounters involving free-floating planets in star clusters
• MASSIVE: A Bayesian analysis of giant planet populations around low-mass stars
• Planet formation around M dwarfs via disc instability: Fragmentation conditions and protoplanet properties
• A wide-orbit giant planet in the high-mass b Centauri binary system
• The Second Discovery from the COol Companions ON Ultrawide orbiTS (COCONUTS) Program: A Cold Wide-Orbit Exoplanet around a Young Field M Dwarf at 10.9 pc
• Protoplanetary Disc Response to Distant Tidal Encounters in Stellar Clusters
• Planetary Architectures in Interacting Stellar Environments
• The dynamical evolution of low-mass hydrogen-burning stars, brown dwarfs and planetary-mass objects formed through disc fragmentation
• Fragmentation favoured in discs around higher mass stars
• A wide planetary-mass companion to a young low-mass brown dwarf in Ophiuchus
• Hot Jupiter formation in dense clusters: secular chaos in multi-planetary systems
• Giant planet swaps during close stellar encounters
• Zodiacal Exoplanets in Time (ZEIT) XII: A Directly-Imaged Planetary-Mass Companion to a Young Taurus M Dwarf Star
• Making hot Jupiters in stellar clusters: the importance of binary exchange
• On encounter rates in star clusters

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