Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-01-24
Astronomy and Astrophysics
Astrophysics
Accepted for publication in A&A. Alternative download from http://astro.uni-tuebingen.de/publications/author_title.shtml
Scientific paper
10.1051/0004-6361:20053768
We present new medium-resolution high-S/N optical spectra of the ultracompact low-mass X-ray binaries 4U0614+091 and 4U1626-67, taken with the ESO Very Large Telescope. They are pure emission line spectra and the lines are identified as due to C II-IV and O II-III Line identification is corroborated by first results from modeling the disk spectra with detailed non-LTE radiation transfer calculations. Hydrogen and helium lines are lacking in the observed spectra. Our models confirm the deficiency of H and He in the disks. The lack of neon lines suggests an Ne abundance of less than about 10 percent (by mass), however, this result is uncertain due to possible shortcomings in the model atom. These findings suggest that the donor stars are eroded cores of C/O white dwarfs with no excessive neon overabundance. This would contradict earlier claims of Ne enrichment concluded from X-ray observations of circumbinary material, which was explained by crystallization and fractionation of the white dwarf core.
Dreizler Stefan
Hammer Nicolay J.
Nagel Thomas
Rauch Thomas
Werner Kirstin
No associations
LandOfFree
VLT spectroscopy and non-LTE modeling of the C/O-dominated accretion disks in two ultracompact X-ray binaries 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 VLT spectroscopy and non-LTE modeling of the C/O-dominated accretion disks in two ultracompact X-ray binaries, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and VLT spectroscopy and non-LTE modeling of the C/O-dominated accretion disks in two ultracompact X-ray binaries will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-550697