NON-LOCAL THERMAL EQUILIBRIUM MODEL ATMOSPHERES FOR THE HOTTEST WHITE DWARFS: SPECTRAL ANALYSIS OF THE COMPACT COMPONENT IN NOVA V4743 Sgr
Rauch T, Orio M, Gonzales-Riestra R, Nelson T, Still M, Werner K, Wilms J (2010)
Publication Status: Published
Publication Type: Journal article
Publication year: 2010
Journal
Publisher: IOP PUBLISHING LTD
Book Volume: 717
Pages Range: 363-371
Journal Issue: 1
DOI: 10.1088/0004-637X/717/1/363
Abstract
Half a year after its outburst in 2002 September, nova V4743 Sgr evolved into the brightest supersoft X-ray source in the sky with a flux maximum around 30 angstrom. We calculated grids of synthetic energy distributions based on non-local thermal equilibrium model atmospheres for the analysis of the hottest white dwarfs (WDs) and present the result of fits to Chandra and XMM-Newton grating X-ray spectra of V4743 Sgr of outstanding quality, exhibiting prominent resonance lines of C v, C VI, N VI, N VII, and O VII in absorption. The nova reached its highest effective temperature (T(eff) = 740 +/- 70 kK) around 2003 April and remained at that temperature at least until 2003 September. We conclude that the WD is massive, approximate to 1.1-1.2M(circle dot). The nuclear-burning phase lasted for 2-2.5 years after the outburst, probably the average duration for a classical nova. The photosphere of V4743 Sgr was strongly carbon deficient (approximate to 0.01 times solar) and enriched in nitrogen and oxygen (>5 times solar). Especially the very low C/N ratio indicates that the material at the WD's surface underwent thermonuclear burning. Thus, this nova retained some of the accreted material and did not eject all of it in outburst. From 2003 March to September, the nitrogen abundance is strongly decreasing; new material is probably already being accreted at this stage.
Authors with CRIS profile
Involved external institutions
Eberhard Karls Universität Tübingen
Germany (DE)
National Aeronautics and Space Administration (NASA)
United States (USA) (US)
European Space Astronomy Centre (ESAC)
Spain (ES)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
Germany (DE)
National Aeronautics and Space Administration (NASA)
United States (USA) (US)
European Space Astronomy Centre (ESAC)
Spain (ES)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
How to cite
APA:
Rauch, T., Orio, M., Gonzales-Riestra, R., Nelson, T., Still, M., Werner, K., & Wilms, J. (2010). NON-LOCAL THERMAL EQUILIBRIUM MODEL ATMOSPHERES FOR THE HOTTEST WHITE DWARFS: SPECTRAL ANALYSIS OF THE COMPACT COMPONENT IN NOVA V4743 Sgr. Astrophysical Journal, 717(1), 363-371. https://doi.org/10.1088/0004-637X/717/1/363
MLA:
Rauch, T., et al. "NON-LOCAL THERMAL EQUILIBRIUM MODEL ATMOSPHERES FOR THE HOTTEST WHITE DWARFS: SPECTRAL ANALYSIS OF THE COMPACT COMPONENT IN NOVA V4743 Sgr." Astrophysical Journal 717.1 (2010): 363-371.
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