The origin of ultramassive white dwarfs: hints from Gaia EDR3

Abstract

Gaia Data Release 2 revealed a population of ultramassive white dwarfs on the Q branch that are moving anomalously fast for a local disc population with their young photometric ages. As the velocity dispersion of stars in the local disc increases with age, a proposed explanation of these white dwarfs is that they experience a cooling delay that causes current cooling models to infer photometric ages much younger than their true ages. To explore this explanation, we investigate the kinematics of ultramassive white dwarfs within 200 pc of the Sun using the improved Gaia Early Data Release 3 observations. We analyse the transverse motions of 0.95 - 1.25 $M_{\odot }$ white dwarfs, subdivided by mass and age, and determine the distributions of the three-dimensional components of the transverse velocities. The results are compared to expectations based on observed kinematics of local main-sequence stars. We find a population of photometrically young ($\sim$ 0.5 - 1.5 Gyr) ultramassive ($\sim$ 1.15 - 1.25 $M_{\odot }$) white dwarfs for which the transverse velocity component in the direction of Galactic rotation is more dispersed than for local disc stars of any age; thus, it is too dispersed to be explained by any cooling delay in white dwarfs originating from the local disc. Furthermore, the dispersion ratio of the velocity components in the Galactic plane for this population is also inconsistent with a local disc origin. We discuss some possible explanations of this kinematically anomalous population, such as a halo origin or production through dynamical effects of stellar triple systems.

arXiv comment11 pages, 3 figures, published in MNRAS

References in corpus (92)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Gaia mission
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• The Geneva-Copenhagen survey of the Solar neighbourhood: Ages, metallicities, and kinematic properties of 14,000 F and G dwarfs
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• Local stellar kinematics from Hipparcos data
• The Eccentric Kozai-Lidov Effect and Its Applications
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
• The Geneva-Copenhagen Survey of the Solar neighbourhood III. Improved distances, ages, and kinematics
• Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
• Gaia Data Release 2: Mapping the Milky Way disc kinematics
• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• A Catalog of Multiplicity among Bright Stellar Systems
• The Distribution of Nearby Stars in Velocity Space Inferred from Hipparcos Data
• From binaries to multiples II: hierarchical multiplicity of F and G dwarfs
• The Kozai Mechanism and the Evolution of Binary Supermassive Black Holes
• A catalogue of white dwarfs in Gaia EDR3
• Binary black hole mergers from field triples: properties, rates and the impact of stellar evolution
• On the Spectral Evolution of Hot White Dwarf Stars. I. A Detailed Model-Atmosphere Analysis of Hot White Dwarfs from SDSS DR12
• Accelerating Compact Object Mergers in Triple Systems with the Kozai Resonance: A Mechanism for "Prompt" Type Ia Supernovae, Gamma-Ray Bursts, and Other Exotica
• Lidov-Kozai Cycles with Gravitational Radiation: Merging Black Holes in Isolated Triple Systems
• Kinematics and history of the solar neighbourhood revisited
• Black Hole Mergers in Galactic Nuclei Induced by the Eccentric Kozai-Lidov Effect
• The birth of the Milky Way as uncovered by accurate stellar ages with Gaia
• New cooling sequences for old white dwarfs
• Dynamical age differences among coeval star clusters as revealed by blue stragglers
• Vertical distribution of Galactic disk stars IV - AMR and AVR from clump giants
• Rapid Eccentricity Oscillations and the Mergers of Compact Objects in Hierarchical Triples
• Core crystallization and pile-up in the cooling sequence of evolving white dwarfs
• Black Hole and Neutron Star Binary Mergers in Triple Systems: Merger Fraction and Spin-Orbit Misalignment
• A large stellar evolution database for population synthesis studies: VI. White dwarf cooling sequences
• The evolution of stellar triples: The most common evolutionary pathways
• A cooling anomaly of high-mass white dwarfs
• The triple evolution dynamical instability: Stellar collisions in the field and the formation of exotic binaries
• On the evolution of ultra-massive white dwarfs
• Velocity distribution of stars in the solar neighbourhood
• Kinematic modelling of the Milky Way using the RAVE and GCS stellar surveys
• Galactic rotation in Gaia DR1
• Origin and evolution of moving groups I. Characterization in the observational kinematic-age-metallicity space
• Re-visiting the relations: Galactic thin disc age-velocity dispersion relation
• The impact of vector resonant relaxation on the evolution of binaries near a massive black hole: implications for gravitational wave sources
• Population synthesis of triple systems in the context of mergers of carbon-oxygen white dwarfs
• Gaia DR2 reveals a star formation burst in the disc 2-3 Gyr ago
• The distribution of nearby stars in phase space mapped by Hipparcos III. Clustering and streaming among A-F type stars
• The Physics of crystallizing white dwarfs
• A 5D view of the Alpha Per, Pleiades, and Praesepe clusters
• On the age heterogeneity of the Pleiades, Hyades and Sirius moving groups
• Looks can be deceiving: underestimating the age of single white dwarfs due to binary mergers
• Black hole-neutron star mergers from triples
• The Oort Constants Measured from Proper Motions
• The age-velocity dispersion relation of the Galactic discs from LAMOST-Gaia data
• Spin-Orbit Misalignment of Merging Black-Hole Binaries with Tertiary Companions
• An Analytical Portrait of Binary Mergers in Hierarchical Triple Systems
• The rate of WD-WD head-on collisions in isolated triples is too low to explain standard type Ia supernovae
• ${}^{22}$Ne Phase Separation As A Solution To The Ultramassive White Dwarf Cooling Anomaly
• Stellar triples on the edge; Comprehensive overview of the evolution of destabilised triples leading to stellar and binary exotica
• Kinematic groups beyond the Solar neighbourhood with RAVE
• Induced Ellipticity for Inspiraling Binary Systems
• Double white dwarf merger products among high-mass white dwarfs
• Multi-Gigayear White Dwarf Cooling Delays from Clustering-Enhanced Gravitational Sedimentation
• Simulations of common envelope evolution in triple systems: Circumstellar case
• New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution
• Evolutionary sequences for hydrogen-deficient white dwarfs
• Chaotic dynamics of wide triples induced by galactic tides: a novel channel for producing compact binaries, mergers, and collisions
• The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
• Asteroseismology of ZZ Ceti stars with fully evolutionary white dwarf models: I. The impact of the uncertainties from prior evolution on the period spectrum
• Toward Precision Cosmochronology: A New C/O Phase Diagram for White Dwarfs
• The Most Massive White Dwarfs in the Solar Neighborhood
• Search and analysis of blue straggler stars in open clusters
• Forever young white dwarfs: when stellar ageing stops
• Neon Cluster Formation and Phase Separation During White Dwarf Cooling
• The Merger Fraction of Ultramassive White Dwarfs
• Reconstructing the Pleiades with Gaia EDR3
• Merging of Components in Close Binaries: Type Ia Supernovae, Massive White Dwarfs, and Ap stars
• Kinematic properties of white dwarfs. Galactic orbital parameters and age-velocity dispersion relation
• Evolution of massive stellar triples and implications for compact object binary formation
• Local Stellar Kinematics and Oort Constants from the LAMOST A-type Stars
• Return of the TEDI: revisiting the Triple Evolution Dynamical Instability channel in triple stars
• A statistical view on stable and unstable Roche lobe overflow of a tertiary star onto the inner binary in triple systems
• Kinematic structures of the Solar neighbourhood revealed by Gaia DR1/TGAS and RAVE
• Nuclear and dark matter heating in massive white dwarf stars
• The evolution of ultra-massive carbon oxygen white dwarfs
• Cooling Delays from Iron Sedimentation and Iron Inner Cores in White Dwarfs
• The Cooling of Massive White Dwarfs from Gaia EDR3
• Phase Separation in Ultramassive White Dwarfs
• Impact of Convective Boundary Mixing on the TP-AGB
• Formation and Evolution of Blue Stragglers in 47 Tucanae
• Open cluster kinematics with Gaia DR2
• The kinematics of Galactic disc white dwarfs in Gaia DR2
• The velocity distribution of white dwarfs in Gaia EDR3

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