Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2011-12-21
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
Accepted for publication in ApJ Letters
Scientific paper
We report the identification of the double degenerate system NLTT 16249 that comprises a normal, hydrogen-rich (DA) white dwarf and a peculiar, carbon-polluted white dwarf (DQ) showing photospheric traces of nitrogen. We disentangled the observed spectra and constrained the properties of both stellar components. In the evolutionary scenario commonly applied to the sequence of DQ white dwarfs, both carbon and nitrogen would be dredged up from the core. The C/N abundance ratio (~ 50) in the atmosphere of this unique DQ white dwarf suggests the presence of unprocessed material (14N) in the core or in the envelope. Helium burning in the DQ progenitor may have terminated early on the red-giant branch after a mass-ejection event leaving unprocessed material in the core although current mass estimates do not favor the presence of a low-mass helium core. Alternatively, some nitrogen in the envelope may have survived an abridged helium-core burning phase prior to climbing the asymptotic giant-branch. Based on available data, we estimate a relatively short orbital period (P <~ 13 hrs) and on-going spectroscopic observations will help determine precise orbital parameters.
Kawka Adela
Vennes Stephane
No associations
LandOfFree
The Core Composition of a White Dwarf in a Close Double Degenerate System does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Core Composition of a White Dwarf in a Close Double Degenerate System, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Core Composition of a White Dwarf in a Close Double Degenerate System will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-191225