White Dwarf Stars

White dwarf stars are the final stage of most stars, born single or in multiple systems. We discuss the identification, magnetic fields, and mass distribution for white dwarfs detected from spectra obtained by the Sloan Digital Sky Survey up to Data Release 13 in 2016, which lead to the increase in the number of spectroscopically identified white dwarf stars from 5[Formula: see text]000 to 39[Formula: see text]000. This number includes only white dwarf stars with [Formula: see text], i.e., excluding the Extremely Low Mass white dwarfs, which are necessarily the byproduct of stellar interaction.

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White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz960 ◽

2019 ◽

Vol 486 (2) ◽

pp. 2169-2183 ◽

Cited By ~ 24

Author(s):

S O Kepler ◽

Ingrid Pelisoli ◽

Detlev Koester ◽

Nicole Reindl ◽

Stephan Geier ◽

...

Keyword(s):

Survey Data ◽

White Dwarf ◽

White Dwarfs ◽

Main Sequence ◽

Sloan Digital Sky Survey ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Sky Survey ◽

Data Release ◽

Hot Subdwarfs

ABSTRACT White dwarfs carry information on the structure and evolution of the Galaxy, especially through their luminosity function and initial-to-final mass relation. Very cool white dwarfs provide insight into the early ages of each population. Examining the spectra of all stars with 3σ proper motion in the Sloan Digital Sky Survey Data Release 14, we report the classification for 20 088 spectroscopically confirmed white dwarfs, plus 415 hot subdwarfs, and 311 cataclysmic variables. We obtain Teff, log g, and mass for hydrogen atmosphere white dwarf stars (DAs), warm helium atmosphere white dwarfs (DBs), hot subdwarfs (sdBs and sdOs), and estimate photometric Teff for white dwarf stars with continuum spectra (DCs). We find 15 793 sdAs and 447 dCs between the white dwarf cooling sequence and the main sequence, especially below $T_\mathrm{eff}\simeq 10\, 000$ K; most are likely low-mass metal-poor main-sequence stars, but some could be the result of interacting binary evolution.

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A Catalog of Spectroscopically Identified White Dwarf Stars in the First Data Release of the Sloan Digital Sky Survey

The Astrophysical Journal ◽

10.1086/383464 ◽

2004 ◽

Vol 607 (1) ◽

pp. 426-444 ◽

Cited By ~ 168

Author(s):

S. J. Kleinman ◽

Hugh C. Harris ◽

Daniel J. Eisenstein ◽

James Liebert ◽

Atsuko Nitta ◽

...

Keyword(s):

White Dwarf ◽

Sloan Digital Sky Survey ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Sky Survey ◽

Data Release

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New white dwarf stars in the Sloan Digital Sky Survey Data Release 10

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stu2388 ◽

2014 ◽

Vol 446 (4) ◽

pp. 4078-4087 ◽

Cited By ~ 135

Author(s):

S. O. Kepler ◽

I. Pelisoli ◽

D. Koester ◽

G. Ourique ◽

S. J. Kleinman ◽

...

Keyword(s):

Survey Data ◽

White Dwarf ◽

Sloan Digital Sky Survey ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Sky Survey ◽

Data Release

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Asteroseismological Probing of the Thermal Evolution of White Dwarf Stars

Highlights of Astronomy ◽

10.1017/s1539299600009916 ◽

1992 ◽

Vol 9 ◽

pp. 643-645

Author(s):

G. Fontaine ◽

F. Wesemael

Keyword(s):

White Dwarf ◽

White Dwarfs ◽

Main Sequence ◽

Thermal Evolution ◽

Sequence Evolution ◽

Helium Burning ◽

Dwarf Stars ◽

White Dwarf Stars ◽

The Galaxy ◽

Low Mass

AbstractIt is generally believed that the immediate progenitors of most white dwarfs are nuclei of planetary nebulae, themselves the products of intermediate- and low-mass main sequence evolution. Stars that begin their lifes with masses less than about 7-8 M⊙ (i.e., the vast majority of them) are expected to become white dwarfs. Among those which have already had the time to become white dwarfs since the formation of the Galaxy, a majority have burnt hydrogen and helium in their interiors. Consequently, most of the mass of a typical white dwarf is contained in a core made of the products of helium burning, mostly carbon and oxygen. The exact proportions of C and 0 are unknown because of uncertainties in the nuclear rates of helium burning.

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Gaia Data Release 2 catalogue of extremely low-mass white dwarf candidates

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1876 ◽

2019 ◽

Vol 488 (2) ◽

pp. 2892-2903 ◽

Cited By ~ 12

Author(s):

Ingrid Pelisoli ◽

Joris Vos

Keyword(s):

White Dwarf ◽

Theoretical Models ◽

Dwarf Stars ◽

Single Star ◽

Common Envelope ◽

White Dwarf Stars ◽

Final Sample ◽

Data Release ◽

Low Mass ◽

Binary Evolution

ABSTRACT Extremely low-mass white dwarf stars (ELMs) are M < 0.3 M⊙ helium-core white dwarfs born either as a result of a common-envelope phase or after a stable Roche lobe overflow episode in a multiple system. The Universe is not old enough for ELMs to have formed through single-star evolution channels. As remnants of binary evolution, ELMs can shed light onto the poorly understood phase of common-envelope evolution and provide constraints to the physics of mass accretion. Most known ELMs will merge in less than a Hubble time, providing an important contribution to the signal to be detected by upcoming space-based gravitational wave detectors. There are currently less than 150 known ELMs; most were selected by colour, focusing on hot objects, in a magnitude-limited survey of the Northern hemisphere only. Recent theoretical models have predicted a much larger space density for ELMs than estimated observationally based on this limited sample. In order to perform meaningful comparisons with theoretical models and test their predictions, a larger well-defined sample is required. In this work, we present a catalogue of ELM candidates selected from the second data release of Gaia (DR2). We have used predictions from theoretical models and analysed the properties of the known sample to map the space spanned by ELMs in the Gaia Hertzsprung–Russell diagram. Defining a set of colour cuts and quality flags, we have obtained a final sample of 5762 ELM candidates down to Teff ≈ 5000 K.

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Cool Companions to White Dwarf Stars from the Two Micron All Sky Survey All Sky Data Release

The Astronomical Journal ◽

10.1086/517878 ◽

2007 ◽

Vol 134 (1) ◽

pp. 26-42 ◽

Cited By ~ 38

Author(s):

D. W. Hoard ◽

S. Wachter ◽

Laura K. Sturch ◽

Allison M. Widhalm ◽

Kevin P. Weiler ◽

...

Keyword(s):

White Dwarf ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Sky Survey ◽

Data Release

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White Dwarf Stars in the Sloan Digital SKY Survey: Photometry

White Dwarfs ◽

10.1007/978-94-010-0215-8_120 ◽

2003 ◽

pp. 391-392

Author(s):

S. J. Kleinman ◽

T. Takato ◽

A. Nitta ◽

J. Krzesinski

Keyword(s):

White Dwarf ◽

Sloan Digital Sky Survey ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Sky Survey

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Identification of Cool White Dwarfs in the Sloan Digital Sky Survey

International Astronomical Union Colloquium ◽

10.1017/s0252921100058668 ◽

2000 ◽

Vol 176 ◽

pp. 514-514 ◽

Cited By ~ 1

Author(s):

T. S. Metcalfe ◽

A. Mukadam ◽

D. E. Winget ◽

X. Fan ◽

M. A. Strauss ◽

...

Keyword(s):

White Dwarf ◽

White Dwarfs ◽

Luminosity Function ◽

Galactic Disk ◽

Sloan Digital Sky Survey ◽

Dwarf Stars ◽

White Dwarf Stars ◽

The Galaxy ◽

History Of ◽

Cool White Dwarfs

AbstractWe are searching for the coolest white dwarf stars in the galactic disk and halo. The Sloan survey, in due course, will identify an enormous number of new white dwarf stars which will better define the white dwarf luminosity function—an important tool for understanding the age and history of the stellar population of the galaxy. The broadband filter data obtained in the digital photometry phase of the survey will not permit identification of the most interesting of these, the coolest white dwarf stars. This is because the cool main sequence and subdwarf stars become indistinguishable from the white dwarfs in the various colorcolor diagrams. We have interference filters designed to separate out these classes of objects. We have obtained photometry of test fields to complement the Sloan data and identify the population of cool white dwarf stars. These data will ultimately resolve the controversies, based for the most part on small-number statistics, of the location of the turndown in the white dwarf luminosity function for the disk. If the halo is significantly older than the disk, we will find a second peak in the white dwarf luminosity function, at lower luminosities than the disk turndown. Our data will provide the first meaningful constraints on the location of the turndown in the halo white dwarf luminosity function.

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