2023/10/06 by Hailong Yuan, Zhenwei Li, Yuan, Hailong +29
Earth and Planetary Sciences · Physics and Astronomy · #FOS: Physical sciences #Geophysics and Gravity Measurements #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2310.04108
openalex publication_date 2023/10/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Double white dwarf systems are of great astrophysical importance in the field of gravitational wave and Type Ia supernova. While the binary fraction of CO core white dwarf is about a few percents, the extremely low mass white dwarfs are all thought to be within binary systems. In this work, we report the orbital solution of a double degenerate system: J033847.06+413424.24, an extremely low mass He core white dwarf orbiting a CO core white dwarf. With LAMOST and P200, time domain spectroscopic observations have been made and spectral atmosphere parameters are estimated to be T\rm eff∼22500 K and log g∼5.6 dex. Combining Gaia parallax, 3D extinction, and evolution tracks, we estimate a radius of ∼0.12 R\odot and a mass of ∼0.22 M\odot. With the 37 single exposure spectra, the radial velocities are measured and the orbital parameters are estimated to be P=0.1253132(1) days, K1=289±4 km/s and Vsys=-41±3 km/s. The radial velocity based system ephemeris is also provided. The light curves from several photometric surveys show no orbital modulation. The orbital solution suggests that the invisible companion has a minimum mass of about 0.60 M\odot and is ∼0.79 M\odot for an inclination of 60.0∘, indicating most probably a CO core white dwarf. The system is expected to merge in about 1 Gyr. With present period and distance (∼596 pc) it can not irradiate strong enough gravitational wave for LISA. More double degenerate systems are expected to be discovered and parameterized as the LAMOST survey goes on.