Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
arXiv:2203.04034 · doi:10.1051/0004-6361/202243490
Abstract
Context. Brown dwarfs are poorly understood transition objects between stars and planets, with several competing mechanisms having been proposed for their formation. Mass measurements are generally difficult for isolated objects but also for brown dwarfs orbiting low-mass stars, which are often too faint for spectroscopic follow-up. Aims. Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here we present the analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is due to a binary system composed of a brown dwarf orbiting a red dwarf. Methods. Thanks to extensive ground observations and the availability of space observations from Spitzer, it has been possible to obtain accurate estimates of all microlensing parameters, including parallax, source radius and orbital motion of the binary lens. Results. After accurate modeling, we find that the lens is composed of a red dwarf with mass and a brown dwarf with mass , at a projected separation of au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. Percent precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become common with the Roman space telescope.
13 pages, 6 figures
References in corpus (24)
- The Gaia mission
- No large population of unbound or wide-orbit Jupiter-mass planets
- The Gemini Deep Planet Survey -- GDPS
- A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192
- The Solar Neighborhood XXXVII: The Mass-Luminosity Relation for Main Sequence M Dwarfs
- A New Algorithm For Difference Image Analysis
- The Wide Brown Dwarf Binary Oph 1622-2405 and Discovery of A Wide, Low Mass Binary in Ophiuchus (Oph 1623-2402): A New Class of Young Evaporating Wide Binaries?
- Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey II: Free-Floating Planet Detection Rates
- A rich population of free-floating planets in the Upper Scorpius young stellar association
- A Jovian analogue orbiting a white dwarf star
- A high binary fraction for the most massive close-in giant planets and brown dwarf desert members
- A terrestrial-mass rogue planet candidate detected in the shortest-timescale microlensing event
- Deuterium burning in objects forming via the core accretion scenario - Brown dwarfs or planets?
- Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project
- The Two-Colour EMCCD Instrument for the Danish 1.54m Telescope and SONG
- A Parametric Galactic Model toward the Galactic Bulge Based on Gaia and Microlensing Data
- Direct radio discovery of a cold brown dwarf
- Analytic Models of Brown Dwarfs and The Substellar Mass Limit
- A public code for astrometric microlensing with contour integration
- Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VIII. Carbon and oxygen
- Revealing Short-period Exoplanets and Brown Dwarfs in the Galactic Bulge using the Microlensing Xallarap Effect with the \textit{Nancy Grace Roman Space Telescope}
- Shortest Microlensing Event with a Bound Planet: KMT-2016-BLG-2605
- OGLE-2016-BLG-1093Lb: A Sub-Jupiter-mass Spitzer Planet Located in Galactic Bulge
- Identification of stellar-mass black hole binaries and the validity of linear orbital motion approximation in microlensing