Where to find over-massive brown dwarfs: new benchmark systems for binary evolution

Abstract

Under the right conditions brown dwarfs that gain enough mass late in their lives to cross the hydrogen burning limit will not turn into low-mass stars, but rather remain essentially brown dwarf-like. While these objects, called either beige dwarfs or over-massive brown dwarfs, may exist in principle, it remains unclear exactly how they would form astrophysically. We show that accretion from AGB winds, aided by the wind Roche lobe overflow mechanism, is likely to produce a substantial population of observable overmassive brown dwarfs, though other mechanisms are still plausible. Specifically we predict that sun-like stars born with a massive brown dwarf companion on an orbit with a semi-major axis of order 10 AU will likely produce overmassive brown dwarfs, which may be found today as companions to the donor star's remnant white dwarf. The identification and characterization of such an object would produce unique constraints on binary evolution because there is a solid upper limit on the brown dwarf's initial mass.

Accepted at ApJ, includes a new figure showing predictions for Gaia

References in corpus (16)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Mind the gap: The location of the lower edge of the pair instability supernovae black hole mass gap
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• The Initial-Final Mass Relation: Direct Constraints at the Low Mass End
• The Palomar/Keck Adaptive Optics Survey of Young Solar Analogs: Evidence for a Universal Companion Mass Function
• Survival of a brown dwarf after engulfment by a red giant star
• Stellar Evolution in AGN Disks
• The chemical diversity of exo-terrestrial planetary debris around white dwarfs
• The initial-final mass relationship from white dwarfs in common proper motion pairs
• Accretion onto Stars in the Disks of Active Galactic Nuclei
• Stellar Evolution in the Disks of Active Galactic Nuclei Produces Rapidly Rotating Massive Stars
• Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit
• TOI-811b and TOI-852b: New transiting brown dwarfs with similar masses and very different radii and ages from the TESS mission
• Gaia predicted brown dwarf detection rates around FGK stars in astrometry, radial velocity, and photometric transits
• Confirming new white dwarf-ultracool dwarf binary candidates

Cited by in corpus (1)

• A numerical modeling of rotating substellar objects up to mass-shedding limits