Fates of the sub-stellar objects (FOSSO) I. Fates of the known brown dwarfs in main-sequence--BD binaries

Abstract

Context. Understanding the survival and orbital evolution of brown dwarf (BD) companions during the post-main-sequence (MS) evolution of their host stars is increasingly important, especially with recent discoveries of many substellar companions around white dwarfs (WDs). Aims. We investigate the long-term evolution and final outcomes of BDs orbiting low-mass MS stars as these evolve into WDs. By comparing forward-modeling populations with observed WD-BD binaries, we test evolutionary models and predict the existence of yet-undetected systems. Methods. We employ the COMPAS binary population synthesis code to evolve observed MS-BD systems through the post-MS phases of their host stars into the WD stage, tracking orbital changes driven by mass loss, tides, and common-envelope (CE) evolution. Results. Our simulations reproduce a period gap in the distribution of detached WD-BD binaries, consistent with observations. We also identify a boundary separating detached and semi-detached systems on the period-mass diagram, located at orbital periods of $\sim$1-2 hours depending on the BD mass. Conclusions. We predict that a subset of currently known MS-BD binaries will survive post-MS evolution and emerge as detached WD-BD systems, while others will undergo CE evolution and potentially form cataclysmic variables with BD donors. Our results reproduce the observed period gap in WD-BD binaries and provide quantitative predictions for the role of CE efficiency in shaping their distribution. This work predicts that many WD-BD systems remain undetected, motivating targeted searches with microlensing and high-contrast imaging techniques using next-generation large telescopes.

16 pages, 7 figures. Title updated to match the published version. Content unchanged except for metadata

References in corpus (36)

• Post-common-envelope binaries from SDSS. IX: Constraining the common-envelope efficiency
• Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• A Giant Planet Candidate Transiting a White Dwarf
• Survival of a brown dwarf after engulfment by a red giant star
• Monte Carlo simulations of post-common-envelope white dwarf + main sequence binaries: comparison with the SDSS DR7 observed sample
• 3-D selection of 167 sub-stellar companions to nearby stars
• Wide, Cool and Ultracool Companions to Nearby Stars from Pan-STARRS1
• A Jovian analogue orbiting a white dwarf star
• Two white dwarfs in ultrashort binaries with detached, eclipsing, likely substellar companions detected by K2
• Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project
• The substellar companion in the eclipsing white dwarf binary SDSS J141126.20+200911.1
• WD 1856 b: a close giant planet around a white dwarf that could have survived a common-envelope phase
• Close detached white dwarf + brown dwarf binaries: further evidence for low values of the common envelope efficiency
• White dwarf binaries suggest a common envelope efficiency $\alpha \sim 1/3$
• A near-infrared spectroscopic detection of the brown dwarf in the post common envelope binary WD0137-349
• The thermal equilibrium mass loss model and its applications in binary evolution
• Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit
• Fourteen new eclipsing white dwarf plus main-sequence binaries from the SDSS and Catalina surveys
• Triage of Astrometric Binaries - how to find triple systems and dormant black-hole secondaries in the Gaia orbits
• COol Companions ON Ultrawide orbiTS (COCONUTS). I. A High-Gravity T4 Benchmark around an Old White Dwarf and A Re-Examination of the Surface-Gravity Dependence of the L/T Transition
• The Common Envelope Evolution Outcome -- A Case Study on Hot Subdwarf B Stars
• WD1032+011, an inflated brown dwarf in an old eclipsing binary with a white dwarf
• The White Dwarf Binary Pathways Survey IV: Three close white dwarf binaries with G-type secondary stars
• SDSS J105754.25+275947.5: a period-bounce eclipsing cataclysmic variable with the lowest-mass donor yet measured
• Successive common envelope events from multiple planets
• Evidence for mass accretion driven by spiral shocks onto the white dwarf in SDSS J123813.73-033933.0
• Criteria for Dynamical Timescale Mass Transfer of Metal-poor Intermediate-mass Stars
• A brown dwarf donor and an optically thin accretion disc with a complex stream impact region in the period-bouncer candidate BW Sculptoris
• An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf
• Observation of undepleted phosphine in the atmosphere of a low-temperature brown dwarf
• Discovery of a resolved white dwarf-brown dwarf binary with a small projected separation: SDSS J222551.65+001637.7AB
• Minimum Orbital Periods of H-Rich Bodies
• Primeval very low-mass stars and brown dwarfs -- VIII. The first age benchmark L subdwarf, a wide companion to a halo white dwarf
• Searching for substellar companion candidates with Gaia. II. A catalog of 9,698 planet candidate solar-type hosts
• Phase-resolved Hubble Space Telescope WFC3 Spectroscopy of Weakly-Irradiated Brown Dwarf GD 1400 and Energy Redistribution-Irradiation Trends in Six WD$-$BD Binaries