A Characterization of the Circumstellar Gas around WD 1124-293 using Cloudy
arXiv:2010.12667 · doi:10.3847/1538-4357/abc262
Abstract
Between 30 - 50% of white dwarfs (WDs) show heavy elements in their atmospheres. This "pollution" is thought to arise from the accretion of planetesimals perturbed by outer planet(s) to within the WD's tidal disruption radius. A small fraction of these WDs show either emission or absorption from circumstellar (C-S) gas. The abundances of metals in the photospheres of WDs with C-S gas are mostly similar to the bulk composition of the Earth. The C-S component arises from gas produced through collisions and/or the sublimation of disintegrating planetesimals. High resolution spectroscopic observations of WD 1124-293 reveal photospheric and C-S absorption of Ca in multiple transitions. Here, we present high signal-to-noise ratio spectra, an updated WD atmosphere analysis, and a self-consistent model of its C-S gas. We constrain the abundances of Ca, Mg, and Fe in the photosphere of WD 1124-293, and find agreement with the abundances of these 3 species in the C-S gas. We find the location of the C-S gas is about a hundred white dwarf radii, the C-S and photospheric compositions are thus far consistent, the gas is not isothermal, and the amount of C-S Ca has not changed in two decades. We also demonstrate how to use Cloudy to model C-S gas viewed in absorption around polluted WDs. Modeling the abundances of C-S gas around polluted WDs with Cloudy provides a new method to measure the composition of exo-planetesimals and will allow a direct comparison to the composition of rocky bodies in the Solar System.
Accepted for publication in The Astrophysical Journal, 13 pages, 9 figures, 4 tables
References in corpus (12)
- The frequency of planetary debris around young white dwarfs
- Formation of planetary debris discs around white dwarfs I: Tidal disruption of an extremely eccentric asteroid
- Externally-polluted white dwarfs with dust disks
- A planetesimal orbiting within the debris disc around a white dwarf star
- Accretion of a giant planet onto a white dwarf
- Variable Emission from a Gaseous Disc around a Metal-Polluted White Dwarf
- Compositions of Planetary Debris around Dusty White Dwarfs
- The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 Parsec White Dwarf Sample
- Evidence for eccentric, precessing gaseous debris in the circumstellar absorption towards WD 1145+017
- Modeling of the Variable Circumstellar Absorption Features of WD 1145+017
- First Detection of Hydrogen in the β Pictoris Gas Disk
- The gaseous debris disk of the white dwarf SDSS J1228+1040. HST/COS search for far-ultraviolet signatures