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The velocity distribution of white dwarfs in Gaia EDR3

Mikkola, Daniel LU ; Mcmillan, Paul J. LU orcid ; Hobbs, David LU orcid and Wimarsson, John (2022) In Monthly Notices of the Royal Astronomical Society 512(4). p.6201-6216
Abstract

Using a penalized maximum likelihood, we estimate, for the first time, the velocity distribution of white dwarfs in the solar neighbourhood. Our sample consists of 129 675 white dwarfs within 500 pc in Gaia Early Data Release 3. The white dwarf velocity distributions reveal a similar structure to the rest of the solar neighbourhood stars, reflecting that white dwarfs are subject to the same dynamical processes. In the velocity distribution for three magnitude-binned subsamples, we, however, find a novel structure at (U, V) = (7,-19) km s-1 in fainter samples, potentially related to the Coma Berenices stream. We also see a double-peaked feature in U-W at U ≈-30 km s-1 and in V-W at V ≈-20 km s-1 for fainter samples. We determine the... (More)

Using a penalized maximum likelihood, we estimate, for the first time, the velocity distribution of white dwarfs in the solar neighbourhood. Our sample consists of 129 675 white dwarfs within 500 pc in Gaia Early Data Release 3. The white dwarf velocity distributions reveal a similar structure to the rest of the solar neighbourhood stars, reflecting that white dwarfs are subject to the same dynamical processes. In the velocity distribution for three magnitude-binned subsamples, we, however, find a novel structure at (U, V) = (7,-19) km s-1 in fainter samples, potentially related to the Coma Berenices stream. We also see a double-peaked feature in U-W at U ≈-30 km s-1 and in V-W at V ≈-20 km s-1 for fainter samples. We determine the velocity distribution and velocity moments as a function of absolute magnitude for two samples based on the bifurcation identified in Gaia Data Release 2 in the colour-magnitude diagram. The brighter, redder sequence has a larger velocity dispersion than the fainter, bluer sequence across all magnitudes. It is hard to reconcile this kinematic difference with a bifurcation caused purely by atmospheric composition, while it fits neatly with a significant age difference between the two sequences. Our results provide novel insights into the kinematic properties of white dwarfs and demonstrate the power of analytical techniques that work for the large fraction of stars that do not have measured radial velocities in the current era of large-scale astrometric surveys.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Galaxy: Kinematics and dynamics, Galaxy: Structure, methods: Data analysis, methods: Statistical, solar neighbourhood, stars: Kinematics and dynamics
in
Monthly Notices of the Royal Astronomical Society
volume
512
issue
4
pages
16 pages
publisher
Oxford University Press
external identifiers
  • scopus:85130633100
ISSN
0035-8711
DOI
10.1093/mnras/stac434
project
Stellar kinematics in surveys and simulations
language
English
LU publication?
yes
id
9b00bc5c-e412-46ac-9e38-4f464e6e9ae9
date added to LUP
2022-07-14 14:22:53
date last changed
2024-04-18 08:55:45
@article{9b00bc5c-e412-46ac-9e38-4f464e6e9ae9,
  abstract     = {{<p>Using a penalized maximum likelihood, we estimate, for the first time, the velocity distribution of white dwarfs in the solar neighbourhood. Our sample consists of 129 675 white dwarfs within 500 pc in Gaia Early Data Release 3. The white dwarf velocity distributions reveal a similar structure to the rest of the solar neighbourhood stars, reflecting that white dwarfs are subject to the same dynamical processes. In the velocity distribution for three magnitude-binned subsamples, we, however, find a novel structure at (U, V) = (7,-19) km s-1 in fainter samples, potentially related to the Coma Berenices stream. We also see a double-peaked feature in U-W at U ≈-30 km s-1 and in V-W at V ≈-20 km s-1 for fainter samples. We determine the velocity distribution and velocity moments as a function of absolute magnitude for two samples based on the bifurcation identified in Gaia Data Release 2 in the colour-magnitude diagram. The brighter, redder sequence has a larger velocity dispersion than the fainter, bluer sequence across all magnitudes. It is hard to reconcile this kinematic difference with a bifurcation caused purely by atmospheric composition, while it fits neatly with a significant age difference between the two sequences. Our results provide novel insights into the kinematic properties of white dwarfs and demonstrate the power of analytical techniques that work for the large fraction of stars that do not have measured radial velocities in the current era of large-scale astrometric surveys.</p>}},
  author       = {{Mikkola, Daniel and Mcmillan, Paul J. and Hobbs, David and Wimarsson, John}},
  issn         = {{0035-8711}},
  keywords     = {{Galaxy: Kinematics and dynamics; Galaxy: Structure; methods: Data analysis; methods: Statistical; solar neighbourhood; stars: Kinematics and dynamics}},
  language     = {{eng}},
  number       = {{4}},
  pages        = {{6201--6216}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{The velocity distribution of white dwarfs in Gaia EDR3}},
  url          = {{http://dx.doi.org/10.1093/mnras/stac434}},
  doi          = {{10.1093/mnras/stac434}},
  volume       = {{512}},
  year         = {{2022}},
}