scholarly journals The kinematics of white dwarfs from the SDSS DR12

2017 ◽  
Vol 13 (S334) ◽  
pp. 294-295
Author(s):  
E. García–Berro ◽  
G. Skorobogatov ◽  
S. Torres ◽  
B. Anguiano ◽  
A. Rebassa-Mansergas
Keyword(s):  
White Dwarfs ◽  
Galactic Plane ◽  
Galactic Disk ◽  
Three Dimensional ◽  
Radial Distance ◽  
Sloan Digital Sky Survey ◽  
Original Sample ◽  
Proper Motions ◽  
Sky Survey ◽  
Data Release

AbstractWe use the Sloan Digital Sky Survey Data Release 12, which is the largest available white dwarf catalogue to date, to study the evolution of the kinematical properties of the population of white dwarfs of the Galactic disk. We derive masses, ages, photometric distances and radial velocities for all white dwarfs with hydrogen-rich atmospheres. For those stars for which proper motions from the USNO-B1 catalogue are available, the three-dimensional components of the velocity are obtained. This subset of the original sample comprises 20,247 stars, making it the largest sample of white dwarfs with measured three-dimensional velocities. The volume probed by our sample is large, allowing us to obtain relevant kinematical information. In particular, our sample extends from a Galactocentric radial distance RG = 7.8 to 9.3 kpc, and vertical distances from the Galactic plane ranging from Z = +0.5 to –0.5 kpc.

scholarly journals White Dwarf Stars

2017 ◽  
Vol 45 ◽  
pp. 1760023
Author(s):  
S. O. Kepler ◽  
Alejandra Daniela Romero ◽  
Ingrid Pelisoli ◽  
Gustavo Ourique
Keyword(s):  
White Dwarf ◽  
Final Stage ◽  
White Dwarfs ◽  
Sloan Digital Sky Survey ◽  
Dwarf Stars ◽  
Multiple Systems ◽  
White Dwarf Stars ◽  
Sky Survey ◽  
Data Release ◽  
Low Mass

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.

scholarly journals Magnetic white dwarfs in the Early Data Release of the Sloan Digital Sky Survey

2002 ◽  
Vol 394 (3) ◽  
pp. 957-963 ◽  
Author(s):  
B. T. Gänsicke ◽  
F. Euchner ◽  
S. Jordan
Keyword(s):  
White Dwarfs ◽  
Sloan Digital Sky Survey ◽  
Early Data ◽  
Sky Survey ◽  
Data Release

scholarly journals The kinematics of the white dwarf population from the SDSS DR12

2017 ◽  
Vol 12 (S330) ◽  
pp. 201-202
Author(s):  
B. Anguiano ◽  
A. Rebassa-Mansergas ◽  
E. García-Berro ◽  
S. Torres ◽  
K. Freeman ◽  
...  
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Galactic Plane ◽  
Three Dimensional ◽  
Radial Distance ◽  
Space Velocity ◽  
Galactic Disc ◽  
Present Sample ◽  
Secular Evolution ◽  
The North

AbstractWe use the Sloan Digital Sky Survey Data Release 12, which is the largest available white dwarf catalog to date, to study the evolution of the kinematical properties of the population of white dwarfs in the Galactic disc. We derive masses, ages, photometric distances and radial velocities for all white dwarfs with hydrogen-rich atmospheres. For those stars for which proper motions from the USNO-B1 catalog are available the true three-dimensional components of the stellar space velocity are obtained. This subset of the original sample comprises 20,247 objects, making it the largest sample of white dwarfs with measured three-dimensional velocities. Furthermore, the volume probed by our sample is large, allowing us to obtain relevant kinematical information. In particular, our sample extends from a Galactocentric radial distance RG = 7.8 kpc to 9.3 kpc, and vertical distances from the Galactic plane ranging from Z = −0.5 kpc to 0.5 kpc. We examine the mean components of the stellar three-dimensional velocities, as well as their dispersions with respect to the Galactocentric and vertical distances. We confirm the existence of a mean Galactocentric radial velocity gradient, ∂〈VR〉/∂RG = −3 ± 5 km s−1 kpc−1. We also confirm North-South differences in 〈Vz〉. Specifically, we find that white dwarfs with Z > 0 (in the North Galactic hemisphere) have 〈Vz〉 < 0, while the reverse is true for white dwarfs with Z < 0. The age-velocity dispersion relation derived from the present sample indicates that the Galactic population of white dwarfs may have experienced an additional source of heating, which adds to the secular evolution of the Galactic disc.

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

2019 ◽  
Vol 486 (2) ◽  
pp. 2169-2183 ◽  
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.

scholarly journals Analysis of cool DO-type white dwarfs from the Sloan Digital Sky Survey data release 10

2014 ◽  
Vol 572 ◽  
pp. A117 ◽  
Author(s):  
N. Reindl ◽  
T. Rauch ◽  
K. Werner ◽  
S. O. Kepler ◽  
B. T. Gänsicke ◽  
...  
Keyword(s):  
Survey Data ◽  
White Dwarfs ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Data Release

scholarly journals Carbon-rich (DQ) white dwarfs in the Sloan Digital Sky Survey

2019 ◽  
Vol 628 ◽  
pp. A102 ◽  
Author(s):  
D. Koester ◽  
S. O. Kepler
Keyword(s):  
White Dwarfs ◽  
Sloan Digital Sky Survey ◽  
Significant Fraction ◽  
Atmospheric Parameters ◽  
Spectral Evolution ◽  
Large Sample ◽  
Synthetic Spectra ◽  
Sky Survey ◽  
Data Release

Context. Among the spectroscopically identified white dwarfs, a fraction smaller than 2% have spectra dominated by carbon lines, mainly molecular C2, but also a smaller group dominated by C I and C II lines. These are together called DQ white dwarfs. Aims. We want to derive atmospheric parameters Teff, log g, and carbon abundances for a large sample of these stars and discuss implications for their spectral evolution. Methods. Sloan Digital Sky Survey spectra and ugriz photometry were used, together with Gaia Data Release 2 parallaxes and G band photometry. These were fitted to synthetic spectra and theoretical photometry derived from model atmospheres. Results. We found that the DQ hotter than Teff ~ 10 000 K have masses ~ 0.4 M⊙ larger than the classical DQ, which have masses typical for the majority of white dwarfs (~ 0.6 M⊙). We found some evidence that the peculiar DQ below 10 000 K also have significantly larger masses and may thus be the descendants of the hot and warm DQ above 10 000 K. A significant fraction of the hotter objects with Teff > 14 500 K have atmospheres dominated by carbon.

scholarly journals A Catalog of Spectroscopically Confirmed White Dwarfs from the Sloan Digital Sky Survey Data Release 4

2006 ◽  
Vol 167 (1) ◽  
pp. 40-58 ◽  
Author(s):  
Daniel J. Eisenstein ◽  
James Liebert ◽  
Hugh C. Harris ◽  
S. J. Kleinman ◽  
Atsuko Nitta ◽  
...  
Keyword(s):  
Survey Data ◽  
White Dwarfs ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Data Release
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