2018/11/19 by Martí Perpinyà-Vallès, M. Perpinyà-Vallès, A. Rebassa-Mansergas +8
Physics and Astronomy · #Astrometry #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Binary number #Chandrasekhar limit #Gamma-ray bursts and supernovae #Photometry (optics) #Physics #Stars #Stellar, planetary, and galactic studies #Supernova #White dwarf #astro-ph.SR
paper · pdf · doi:10.1093/mnras/sty3149
accepted for publication by MNRAS
arxiv created 2018/11/19 · openalex publication_date 2018/11/20 · arxiv updated 2018/12/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report the discovery of J1953–1019, the first resolved triple white dwarf system. The triplet consists of an inner white dwarf binary and a wider companion. Using Gaia DR2 photometry and astrometry combined with our follow-up spectroscopy, we derive effective temperatures, surface gravities, masses, and cooling ages of the three components. All three white dwarfs have pure-hydrogen (DA) atmospheres, masses of |0.60\hbox--0.63 \mboxM\odot |, and cooling ages of 40–290 Myr. We adopt eight initial-to-final mass relations to estimate the main-sequence progenitor masses (which we find to be similar for the three components, 1.6–2.6 M⊙) and lifetimes. The differences between the derived cooling times and main sequence lifetimes agree for most of the adopted initial-to-final mass relations, hence the three white dwarfs in J1953–1019 are consistent with coeval evolution. Furthermore, we calculate the projected orbital separations of the inner white dwarf binary (303.25 ± 0.01 au) and of the centre of mass of the inner binary and the outer companion (|6398.97± 0.09| au). From these values, and taking into account a wide range of possible configurations for the triplet to be currently dynamically stable, we analyse the future evolution of the system. We find that a collision between the two inner white dwarfs due to Lidov–Kozai oscillations is unlikely, though if it occurs it could result in a sub-Chandrasekhar Type Ia supernova explosion.