Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Carbon-rich (DQ) white dwarfs in the Sloan Digital Sky Survey   Among the spectroscopically identified white dwarfs, a fraction smaller than
2% have spectra dominated by carbon lines, mainly molecular C2, but also in a
smaller group by CI and CII lines. These are together called DQ white dwarfs.
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. 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. We found that the DQs hotter than Teff ~10000 K have masses ~0.4
Msun larger than the cooler ones, which have masses typical for the majority of
white dwarfs, ~0.6 Msun. A significant fraction of the hotter objects with Teff
> 14500 K have atmospheres dominated by carbon.

7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol