Extremely low-mass white dwarf stars observed in Gaia DR2 and LAMOST DR8

Abstract

We present the first results from our ongoing project to study extremely low mass (ELM) white dwarfs (WDs) ($M$ $\le$ 0.3$M_{\sun}$) with the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) spectra. Based on the LAMOST DR8 spectral database, we analyzed 136 ELM WD candidates selected from $Gaia$ DR2 data and 12 known objects previously identified by the ELM Survey. The atmospheric parameters and radial velocities of these stars were obtained by fitting the LAMOST low-resolution spectra. After comparing the atmospheric parameters of the 12 known objects from this work to the results reported by the ELM Survey, we demonstrated the potential of LAMOST spectra in probing into the nature of ELM WDs. Based on the atmospheric parameters and $Gaia$ EDR3 data, we identified 21 new high-probability ELM WDs with masses $M$ $\le$ 0.3$M_{\sun}$ and parallax estimates that agree to within a factor of 3. Two of them, J0338+4134 and J1129+4715, show significant radial velocity variability and are very likely to be binary systems containing at least one ELM WD.

arXiv comment6 figures, 5 tables, accepted for publication in ApJ

References in corpus (55)

• Astropy: A Community Python Package for Astronomy
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• Gaia Data Release 2: The astrometric solution
• MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
• A 3D Dust Map Based on Gaia, Pan-STARRS 1 and 2MASS
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• The First Data Release (DR1) of the LAMOST general survey
• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• An Improved Spectroscopic Analysis of DA White Dwarfs from the Sloan Digital Sky Survey Data Release 4
• New evolutionary sequences for extremely low mass white dwarfs: Homogeneous mass and age determinations, and asteroseismic prospects
• New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12
• Spectroscopic analysis of DA white dwarfs with 3D model atmospheres
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• LISA verification binaries with updated distances from Gaia Data Release 2
• Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing
• Predicting the LISA white dwarf binary population in the Milky Way with cosmological simulations
• A selection of hot subluminous stars in the GALEX survey II. Subdwarf atmospheric parameters
• A 12 minute Orbital Period Detached White Dwarf Eclipsing Binary
• General relativistic orbital decay in a seven-minute-orbital-period eclipsing binary system
• Science with the TianQin Observatory: Preliminary results on Galactic double white dwarf binaries
• The masses of the millisecond pulsar J1012+5307 and its white-dwarf companion
• A New Stellar Atmosphere Grid and Comparisons with HST/STIS Calspec Flux Distributions
• A systematic search of Zwicky Transient Facility data for ultracompact binary LISA-detectable gravitational-wave sources
• Binary Population Synthesis
• The ELM Survey. VIII. 98 Double White Dwarf Binaries
• EL CVn-type binaries - Discovery of 17 helium white dwarf precursors in bright eclipsing binary star systems
• Observationally driven Galactic double white dwarf population for LISA
• Formation of Extremely Low-mass White Dwarfs in Double Degenerates
• The timescale of low-mass proto-helium white dwarf evolution
• 3D Model Atmospheres for Extremely Low-Mass White Dwarfs
• The Thermal Evolution of the Donors in AM CVn Binaries
• Near-Infrared Photometry of Globular Clusters Towards the Galactic Bulge: Observations and Photometric Metallicity Indicators
• Post-merger evolution of carbon-oxygen + helium white dwarf binaries and the origin of R Coronae Borealis and extreme helium stars
• Most Double Degenerate Low Mass White Dwarf Binaries Merge
• Gaia Data Release 2 Catalogue of Extremely-low Mass White Dwarf Candidates
• Gaia EDR3 Parallax Zero-point Offset based on W Ursae Majoris-type Eclipsing Binaries
• Pruning The ELM Survey: Characterizing Candidate Low-Mass White Dwarfs Through Photometric Variability
• Birth of the ELMs: a ZTF survey for evolved cataclysmic variables turning into extremely low-mass white dwarfs
• PSR J1012+5307: a millisecond pulsar with an extremely low-mass white dwarf companion
• Discovery of 36 eclipsing EL CVn binaries found by the Palomar Transient Factory
• Hot subdwarf Atmospheric parameters, Kinematics, and Origins -- Based on 1587 hot subdwarf stars observed in Gaia DR2 and LAMOST DR7
• Gravitational Wave Radiation of Double Degenerates with Extremely low-mass WD companions
• The white dwarf mass-radius relation and its dependence on the hydrogen envelope
• The kinematics of the white dwarf population from the SDSS DR12
• Radial velocity variability and evolution of hot subdwarf stars
• The ELM Survey South. I. An Effective Search for Extremely Low Mass White Dwarfs
• A 1201 s Orbital Period Detached Binary: the First Double Helium Core White Dwarf LISA Verification Binary
• The Merger Rate of Extremely Low Mass White Dwarf Binaries: Links to the Formation of AM CVn Stars and Underluminous Supernovae
• Mass Transfer and Stellar Evolution of the White Dwarfs in AM CVn Binaries
• LAMOST J0140355+392651: An evolved cataclysmic variable donor transitioning to become an extremely low mass white dwarf
• Convection and rotation boosted prescription of magnetic braking: application to the formation of extremely low-mass white dwarfs
• V1224 Cas - an EL CVn-type Eclipsing Binary Consisting of a Helium White Dwarf Precursor and a Delta Scuti Pulsator
• The formation of subdwarf A-type stars
• The McDonald Observatory search for pulsating sdA stars: asteroseismic support for multiple populations

Cited by in corpus (11)

• The ELM Survey South. II. Two dozen new low mass white dwarf binaries
• A Systematic Search for Short-period Close White Dwarf Binary Candidates Based on Gaia EDR3 Catalog and Zwicky Transient Facility Data
• A seven-Earth-radius helium-burning star inside a 20.5-min detached binary
• FX UMa: A New Heartbeat Binary System with Linear and Non-linear Tidal Oscillations and delta Sct Pulsations
• Compact Objects in close orbits as Gravitational Wave Sources: Formation Scenarios and Properties
• Discovery of four new EL CVn-type binaries in the Gaia eclipsing binaries
• J0526+5934: a peculiar ultra-short period double white dwarf
• Unveiling the evolutionary state of three B supergiant stars: PU Gem, $\epsilon$ CMa and $\eta$ CMa
• Searching for new variable white dwarfs: The discovery of the three new pulsating and three new binary systems
• Formation of Extremely Low-mass White Dwarf Binaries Undergoing Enhanced Angular Momentum Loss
• Rotating strange dwarfs and their indistinguishability from white dwarfs