Gaia0007-1605: an old triple system with an inner brown dwarf-white dwarf binary and an outer white dwarf companion
arXiv:2203.05901 · doi:10.3847/2041-8213/ac5a55
Abstract
We identify Gaia0007-1605AC as the first inner brown dwarf-white dwarf binary of a hierarchical triple system in which the outer component is another white dwarf (Gaia0007-1605B). From optical/near-infrared spectroscopy obtained at the Very Large Telescope with the X-Shooter instrument and/or from Gaia photometry plus SED fitting, we determine the effective temperatures and masses of the two white dwarfs (12018+-68 K, 0.54+-0.01 Msun for Gaia0007-1605A and 4445+-116 K, 0.56+-0.05 Msun for Gaia0007-1605B) and the effective temperature of the brown dwarf (1850+-50 K; corresponding to a spectral type L3+-1). By analysing the available TESS light curves of Gaia0007-1605AC we detect a signal at 1.0446+-0.0015 days with an amplitude of 6.25 ppt, which we interpret as the orbital period modulated from irradiation effects of the white dwarf on the brown dwarf's surface. This drives us to speculate that the inner binary evolved through a common envelope phase in the past. Using the outer white dwarf as a cosmochronometer and analysing the kinematic properties of the system, we conclude that the triple system is about 10 Gyr old.
ApJL in press
References in corpus (17)
- The Transiting Exoplanet Survey Satellite
- galpy: A Python Library for Galactic Dynamics
- New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
- astroquery: An Astronomical Web-Querying Package in Python
- Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
- VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
- Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
- A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
- A catalogue of white dwarfs in Gaia EDR3
- Proxima's orbit around Alpha Centauri
- Speckle interferometry at SOAR in 2012 and 2013
- White Dwarf Rotation as a Function of Mass and a Dichotomy of Mode Linewidths: Kepler Observations of 27 Pulsating DA White Dwarfs Through K2 Campaign 8
- White dwarf evolutionary sequences for low-metallicity progenitors: The impact of third dredge-up
- A naked-eye triple system with a nonaccreting black hole in the inner binary
- Random Forest identification of the thin disk, thick disk and halo Gaia-DR2 white dwarf population
- Constraining the solar neighbourhood age-metallicity relation from white dwarf-main sequence binaries
- Uncovering the ultimate planet impostor. An eclipsing brown dwarf in a hierarchical triple with two evolved stars