Serendipitous discovery of a dusty disc around WDJ181417.84-735459.83
Abstract
Spectroscopic observations of white dwarfs reveal that many of them are polluted by exoplanetary material, whose bulk composition can be uniquely probed this way. We present a spectroscopic and photometric analysis of the DA white dwarf WDJ181417.84-735459.83, an object originally identified to have a strong infrared (IR) excess in the 2MASS and WISE catalogues that we confirmed to be intrinsic to the white dwarf, and likely corresponding to the emission of a dusty disc around the star. The finding of Ca, Fe, and Mg absorption lines in two X-SHOOTER spectra of the white dwarf, taken 8 years apart, is further evidence of accretion from a dusty disc. We do not report variability in the absorption lines between these two spectra. Fitting a blackbody model to the IR excess gives a temperature of 910 ± 50 K. We have estimated a total accretion flux from the spectroscopic metal lines of $|\dot{\rm M}| = 1.784 \times 10^{9}\,$g s-1.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2021
- DOI:
- 10.1093/mnras/staa3836
- arXiv:
- arXiv:2012.05731
- Bibcode:
- 2021MNRAS.501.3916G
- Keywords:
-
- accretion;
- accretion discs;
- stars: white dwarfs;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- Accepted for publication in MNRAS. 11 pages, 10 figures, 6 tables