A Massive Magnetic Helium Atmosphere White Dwarf Binary in a Young Star Cluster

Abstract

We have searched the Gaia DR2 catalogue for previously unknown hot white dwarfs in the direction of young open star clusters. The aim of this experiment was to try and extend the initial-final mass relation (IFMR) to somewhat higher masses, potentially providing a tension with the Chandrasekhar limit currently thought to be around 1.38 M${}_{\odot }$. We discovered a particularly interesting white dwarf in the direction of the young $\sim$150 Myr old cluster Messier 47 (NGC 2422). All Gaia indicators (proper motion, parallax, location in the Gaia colour-magnitude diagram) suggest that it is a cluster member. Its spectrum, obtained from Gemini South, yields a number of anomalies: it is a DB (helium-rich atmosphere) white dwarf, it has a large magnetic field (2.5 MG), is of high mass ($\sim$1.06 M${}_{\odot }$) and its colours are very peculiar --- particularly the redder ones ($r$, $i$, $z$ and $y$), which suggest that it has a late-type companion. This is the only magnetized, detached binary white dwarf with a non-degenerate companion of any spectral type known in or out of a star cluster. If the white dwarf is a cluster member, as all indicators suggest, its progenitor had a mass just over 6 M${}_{\odot }$. It may, however, be telling an even more interesting story than the one related to the IFMR, one about the origin of stellar magnetic fields, Type I supernovae and gravitational waves from low mass stellar systems.

arXiv comment10 pages, 7 figures, accepted for publication in Astrophysical Journal

References in corpus (31)

• Gaia Data Release 2. Summary of the contents and survey properties
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• The VizieR database of Astronomical Catalogues
• Astrophysical parameters of Galactic open clusters
• The Formation Rate, Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey
• A $Gaia$ Data Release 2 catalogue of white dwarfs and a comparison with SDSS
• Evolution of asymptotic giant branch stars I. Updated synthetic TP-AGB models and their basic calibration
• Empirical extinction coefficients for the GALEX, SDSS, 2MASS and WISE passbands
• Magnetic White Dwarfs
• The White Dwarf Initial-Final Mass Relation for Progenitor Stars From 0.85 to 7.5 M${}_{\odot }$
• Super and massive AGB stars - IV. Final fates - Initial to final mass relation
• The VST Photometric Halpha Survey of the Southern Galactic Plane and Bulge (VPHAS+)
• Cataclysmic Variables from SDSS I. The First Results
• A prevalence of dynamo-generated magnetic fields in the cores of intermediate-mass stars
• On the evolution of ultra-massive white dwarfs
• White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14
• The Field White Dwarf Mass Distribution
• An Empirical Measurement of the Initial-Final Mass Relation with Gaia White Dwarfs
• Fundamental parameter accuracy of DA and DB white dwarfs in Gaia Data Release 2
• A First Look at White Dwarf - M Dwarf Pairs in the Sloan Digital Sky Survey (SDSS)
• New full evolutionary sequences of H and He atmosphere massive white dwarf stars using MESA
• The Initial-Final Mass Relation among White Dwarfs in Wide Binaries
• Constraints on the origin of the massive, hot, and rapidly rotating magnetic white dwarf RE J 0317-853 from an HST parallax measurement
• A Young Ultramassive White Dwarf in the AB Doradus Moving Group
• Gravitational Radiation from Strongly Magnetized White Dwarfs
• On the origin of the ultramassive white dwarf GD50
• Genesis of magnetic fields in isolated white dwarfs
• A Novel Approach to Constrain Rotational Mixing & Convective-Core Overshoot in Stars Using the Initial-Final Mass Relation
• Enigmas from the Sloan Digital Sky Survey DR7 Kleinman White Dwarf Catalog
• Improved Main Sequence Turnoff Ages of Young Open Clusters: Multicolor UBV Techniques & the Challenges of Rotation
• An Ultramassive 1.28 M${}_{\odot }$ White Dwarf in NGC 2099

Cited by in corpus (12)

• $\text{Gaia}$ white dwarfs within 40 pc I: spectroscopic observations of new candidates
• Multiple channels for the onset of magnetism in isolated white dwarfs
• Massive White Dwarfs in Young Star Clusters
• Discovery of a Sirius-like binary system with a very strongly magnetic white dwarf. Binarity among magnetic white dwarfs
• Intermediate-Mass Stars Become Magnetic White Dwarfs
• The first catalog of candidate white dwarf-main sequence binaries in open star clusters: A new window into common envelope evolution
• Spectrophotometric analysis of magnetic white dwarf II: Helium-rich compositions
• White dwarf-open cluster associations based on Gaia DR2
• Uncovering new white dwarf - open cluster associations using Gaia DR3
• The Initial-Final Mass Relation for Hydrogen-Deficient White Dwarfs
• The pulsational properties of ultra-massive DB white dwarfs with carbon-oxygen cores coming from single-star evolution
• When Do Stars Go BOOM?