On the potential origin of the circumbinary planet Delorme 1 (AB)b

Abstract

Many circumbinary gas giant planets have been recently discovered. The formation mechanism of circumbinary planets on wide orbits is unclear. We investigate the formation of Delorme 1 (AB)b, a 13$\pm$5M${}_{\mathrm{J}}$ planet, orbiting its host binary at 84AU. The planet is accreting while having an estimated age of 40Myr, which is unexpected, as this process should have ceased due to the dissipation of the protoplanetary disc. Using the Smoothed Particle Hydrodynamics code SEREN, we model three formation scenarios for this planet. In Scenario I the planet forms in-situ on a wide orbit in a massive disc (by gravitational instability), in Scenario II closer to the binary in a massive disc (by gravitational instability), and in Scenario III much closer to the binary in a less massive disc (by core accretion). Planets in Scenario I stay at the observed separation, have mass accretion rates consistent with observed value, but their final mass is too high. In Scenario II, the planet reaches the observed separation through outward migration or scattering by the binary, and has mass accretion rate comparable to the observed; however, the planet mass is above the observed value. In Scenario III, the planet's final mass and mass accretion rate are comparable to the observed ones but the planet's separation is smaller. We conclude that all models may explain some features of the observations but not all of them, raising questions about how gas is accreted onto the planet from its circumplanetary disc, and of the presumed age of the system.

References in corpus (14)

• SPLASH: An interactive visualisation tool for Smoothed Particle Hydrodynamics simulations
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• The Two Modes of Gas Giant Planet Formation
• Radiative transfer and the energy equation in SPH simulations of star formation
• On the Viability of the Magnetorotational Instability in Circumplanetary Disks
• The properties of discs around planets and brown dwarfs as evidence for disc fragmentation
• Planet Formation Theory in the Era of ALMA and Kepler: from Pebbles to Exoplanets
• Strong H$\alpha$ emission and signs of accretion in a circumbinary planetary mass companion from MUSE
• Near-infrared Accretion Signatures from the Circumbinary Planetary Mass Companion Delorme 1 (AB)b
• Emission line variability of young 10-30 Mjup companions : I. The case of GQ Lup b and GSC 06214-00210 b
• N-body simulations of planet formation via pebble accretion II. How various giant planets form
• Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b: Indications of magnetospheric accretion
• Formation of wide-orbit gas giants near the stability limit in multi-stellar systems
• Planet migration in massive circumbinary discs

Cited by in corpus (1)

• ExoplaNeT accRetion mOnitoring sPectroscopic surveY (ENTROPY) - II. Time series of Balmer line profiles of Delorme 1(AB)b