Tremblay, PE;
Hollands, MA;
Gentile Fusillo, NP;
McCleery, J;
Izquierdo, P;
Gänsicke, BT;
Cukanovaite, E;
... Torres, S; + view all
(2020)
Gaia white dwarfs within 40 pc - I. Spectroscopic observations of new candidates.
Monthly Notices of the Royal Astronomical Society
, 497
(1)
pp. 130-145.
10.1093/mnras/staa1892.
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Abstract
We present a spectroscopic survey of 230 white dwarf candidates within 40 pc of the Sun from the William Herschel Telescope and Gran Telescopio Canarias. All candidates were selected from Gaia Data Release 2 (DR2) and in almost all cases, had no prior spectroscopic classifications. We find a total of 191 confirmed white dwarfs and 39 main-sequence star contaminants. The majority of stellar remnants in the sample are relatively cool (<Teff> = 6200 K), showing either hydrogen Balmer lines or a featureless spectrum, corresponding to 89 DA and 76 DC white dwarfs, respectively. We also recover two DBA white dwarfs and 9-10 magnetic remnants. We find two carbon-bearing DQ stars and 14 new metal-rich white dwarfs. This includes the possible detection of the first ultra-cool white dwarf with metal lines. We describe three DZ stars for which we find at least four different metal species, including one that is strongly Fe- and Ni-rich, indicative of the accretion of a planetesimal with core-Earth composition. We find one extremely massive (1.31 ± 0.01 M☉) DA white dwarf showing weak Balmer lines, possibly indicating stellar magnetism. Another white dwarf shows strong Balmer line emission but no infrared excess, suggesting a low-mass sub-stellar companion. A high spectroscopic completeness (>99 per cent) has now been reached for Gaia DR2 sources within 40-pc sample, in the Northern hemisphere (δ > 0◦) and located on the white dwarf cooling track in the Hertzsprung-Russell diagram. A statistical study of the full northern sample is presented in a companion paper.
| Type: | Article |
|---|---|
| Title: | Gaia white dwarfs within 40 pc - I. Spectroscopic observations of new candidates |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staa1892 |
| Publisher version: | http://dx.doi.org/10.1093/mnras/staa1892 |
| Language: | English |
| Additional information: | © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society |
| Keywords: | stars: statistics, white dwarfs, solar neighbourhood |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10112347 |
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