A Photometric and Spectroscopic Investigation of the DB White Dwarf Population Using SDSS and Gaia Data

We present a comprehensive analysis of DB white dwarfs drawn from the Sloan Digital Sky Survey, based on model fits to ugriz photometry and medium-resolution spectroscopy from the Sloan Digital Sky Survey. We also take advantage of the exquisite trigonometric parallax measurements recently obtained by the Gaia mission. Using the so-called photometric and spectroscopic techniques, we measure the atmospheric and physical parameters of each object in our sample (Teff, , , Ca/He, R, M), and compare the values obtained from both techniques in order to assess the precision and accuracy of each method. We then explore in great detail the surface gravity, stellar mass, and hydrogen abundance distributions of DB white dwarfs as a function of effective temperature. We present some clear evidence for a large population of unresolved double-degenerate binaries composed of DB+DB and even DB+DA white dwarfs. In the light of our results, we finally discuss the spectral evolution of DB white dwarfs, in particular the evolution of the DB-to-DA ratio as a function of Teff, and we revisit the question of the origin of hydrogen in DBA white dwarfs.

[1]  S. Coutu,et al.  On the Measurement of Fundamental Parameters of White Dwarfs in the Gaia Era , 2019, The Astrophysical Journal.

[2]  P. Bergeron,et al.  A Comprehensive Spectroscopic and Photometric Analysis of DA and DB White Dwarfs from SDSS and Gaia , 2019, The Astrophysical Journal.

[3]  M. Hollands,et al.  Fundamental parameter accuracy of DA and DB white dwarfs inGaiaData Release 2 , 2018, Monthly Notices of the Royal Astronomical Society.

[4]  B. Freytag,et al.  Pure-helium 3D model atmospheres of white dwarfs , 2018, Monthly Notices of the Royal Astronomical Society.

[5]  M. Hollands,et al.  AGaiaData Release 2 catalogue of white dwarfs and a comparison with SDSS , 2018, Monthly Notices of the Royal Astronomical Society.

[6]  Warren R. Brown,et al.  A refined search for pulsations in white dwarf companions to millisecond pulsars★ , 2018, Monthly Notices of the Royal Astronomical Society.

[7]  H. Rix,et al.  An Empirical Measurement of the Initial–Final Mass Relation with Gaia White Dwarfs , 2018, The Astrophysical Journal.

[8]  T. A. Lister,et al.  Gaia Data Release 2. Summary of the contents and survey properties , 2018, 1804.09365.

[9]  G. Fontaine,et al.  On the Spectral Evolution of Helium-atmosphere White Dwarfs Showing Traces of Hydrogen , 2018, 1803.05965.

[10]  G. Fontaine,et al.  Measurements of Physical Parameters of White Dwarfs: A Test of the Mass–Radius Relation , 2017, 1709.02324.

[11]  University College London,et al.  Trace hydrogen in helium atmosphere white dwarfs as a possible signature of water accretion , 2017, 1702.06542.

[12]  P. Bergeron,et al.  A SPECTROSCOPIC SEARCH FOR CHEMICALLY STRATIFIED WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY , 2016 .

[13]  B. Zuckerman,et al.  Solar abundances of rock-forming elements, extreme oxygen and hydrogen in a young polluted white dwarf , 2016, 1608.07278.

[14]  S. O. Kepler,et al.  New white dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 12 , 2015, 1510.08409.

[15]  S. O. Kepler,et al.  DB white dwarfs in the Sloan Digital Sky Survey Data Release 10 and 12 , 2015, 1509.08244.

[16]  B. Gänsicke,et al.  Magnetic White Dwarfs , 2015, 1504.08072.

[17]  J. Farihi,et al.  Likely detection of water-rich asteroid debris in a metal-polluted white dwarf , 2015, 1503.07864.

[18]  Paolo Giommi,et al.  New white dwarf stars in the Sloan Digital Sky Survey Data Release 10 , 2014, 1411.4149.

[19]  P. Bergeron,et al.  COMPARISON OF ATMOSPHERIC PARAMETERS DETERMINED FROM SPECTROSCOPY AND PHOTOMETRY FOR DA WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY , 2014, 1410.5255.

[20]  B. Gaensicke,et al.  Hydrogen delivery onto white dwarfs from remnant exo-Oort cloud comets , 2014, 1409.7691.

[21]  H. Ludwig,et al.  Spectroscopic analysis of DA white dwarfs with 3D model atmospheres , 2013, 1309.0886.

[22]  B. Freytag,et al.  Pure-hydrogen 3D model atmospheres of cool white dwarfs , 2013, 1302.2013.

[23]  M. Ruiz,et al.  A SPECTROSCOPIC SURVEY AND ANALYSIS OF BRIGHT, HYDROGEN-RICH WHITE DWARFS , 2011, 1109.3171.

[24]  P. Bergeron,et al.  AN IMPROVED SPECTROSCOPIC ANALYSIS OF DA WHITE DWARFS FROM THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 4 , 2011, 1102.0056.

[25]  J. Liebert,et al.  A COMPREHENSIVE SPECTROSCOPIC ANALYSIS OF DB WHITE DWARFS , 2011, 1105.5433.

[26]  P. Bergeron,et al.  A SPECTROSCOPIC ANALYSIS OF WHITE DWARFS IN THE KISO SURVEY , 2010, 1003.4313.

[27]  D. Homeier,et al.  High-resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia Progenitor Survey - III. DA white dwarfs , 2009, 0908.2322.

[28]  P. Dufour,et al.  SPECTROSCOPIC ANALYSIS OF THE WHITE DWARF KUV 02196+2816: A NEW UNRESOLVED DA+DB DEGENERATE BINARY , 2009, 0902.3640.

[29]  J. Liebert,et al.  Hot DQ White Dwarfs: Something Different , 2008, 0805.0331.

[30]  J. Liebert,et al.  White dwarf stars with carbon atmospheres , 2007, Nature.

[31]  S. O. Kepler,et al.  SDSS DR7 WHITE DWARF CATALOG , 2007, 1212.1222.

[32]  Norbert Christlieb,et al.  High-resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia progenitor survey - II. DB and DBA stars , 2007, 0706.2936.

[33]  James Liebert,et al.  A Catalog of Spectroscopically Confirmed White Dwarfs from the Sloan Digital Sky Survey Data Release 4 , 2006, astro-ph/0606700.

[34]  Paul S. Smith,et al.  Hot DB White Dwarfs from the Sloan Digital Sky Survey , 2006, astro-ph/0606702.

[35]  F. Herwig,et al.  The Elemental Abundances in Bare Planetary Nebula Central Stars and the Shell Burning in AGB Stars , 2005, astro-ph/0512320.

[36]  David G. Monet,et al.  The White Dwarf Luminosity Function from Sloan Digital Sky Survey Imaging Data , 2005, astro-ph/0510820.

[37]  P. Bergeron,et al.  The Formation Rate and Mass and Luminosity Functions of DA White Dwarfs from the Palomar Green Survey , 2004, astro-ph/0406657.

[38]  Bhasker K. Moorthy,et al.  The First Data Release of the Sloan Digital Sky Survey , 2003, astro-ph/0305492.

[39]  Pierre Brassard,et al.  The Potential of White Dwarf Cosmochronology , 2001 .

[40]  Maria Teresa Ruiz,et al.  The Chemical Evolution of Cool White Dwarfs and the Age of the Local Galactic Disk , 1997 .

[41]  James Liebert,et al.  A spectroscopic determination of the mass distribution of DA white dwarfs , 1992 .

[42]  S. Vennes,et al.  How much hydrogen is there in a white dwarf , 1991 .

[43]  I. Iben.  On the consequences of low-mass white dwarf mergers , 1990 .

[44]  J. Liebert.  SEARCHES FOR MAGNETIC FIELDS IN WHITE DWARFS SINCE BABCOCK , 1988 .

[45]  C. Hansen,et al.  Temperatures for Hot and Pulsating DB White Dwarfs Obtained with the IUE Observatory , 1986 .

[46]  G. Fontaine,et al.  Carbon pollution in helium-rich white dwarf atmospheres: time-dependent calculations of the dredge-up process , 1986 .

[47]  Edward M. Sion,et al.  A Catalog of Spectroscopically Identified White Dwarfs , 1987 .