Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· On-line Data
· References in the article
· Citations to the Article (21) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (7)
· NED Objects (2)
· Also-Read Articles (Reads History)
· Translate This Page
RX J0045.4+4154: A recurrent supersoft x-ray transient in M31
White, N. E.; Giommi, P.; Heise, J.; Angelini, L.; Fantasia, S.
AA(NASA Goddard Space Flight Center, Greenbelt, Maryland, US), AB(NASA Goddard Space Flight Center, Greenbelt, Maryland, US), AC(NASA Goddard Space Flight Center, Greenbelt, Maryland, US), AD(NASA Goddard Space Flight Center, Greenbelt, Maryland, US), AE(NASA Goddard Space Flight Center, Greenbelt, Maryland, US)
Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 445, no. 2, p. L125-L128 (ApJL Homepage)
Publication Date:
NASA/STI Keywords:
Emission Spectra, Novae, Stellar Activity, Stellar Temperature, White Dwarf Stars, X Ray Astronomy, X Ray Spectra, X Ray Stars, Density (Number/Volume), Hydrogen, Rosat Mission, Stellar Luminosity
Bibliographic Code:


Using data extracted from the ROSAT archive we have discovered a recurrent supersoft X-ray transient RX J0045.4+4154 in M31. The first outburst began on 1992 February 2 and continued for at least 4 days, until the end of the observation sequence. A second outburst that lasted more than 6 days was seen to begin on 1993 January 7. The X-ray spectrum on both occasions yields a characteristic blackbody temperature of approximately 90 eV. For a range of plausible continuum models, the hydrogen column density is (0.8-1.5) x 1021/sq cm and is consistent with the source being located in M31. This implies an unabsorbed 0.1-2.0 keV peak luminosity of approximately 1038 ergs/sec. This is the first recurrent X-ray transient to be found in M31 and is particularly notable because it is much softer than the bright X-ray transients seen in our Galaxy. The spectrum is characteristic of the supersoft class of X-ray sources, which are thought to be accreting white dwarfs that have a hydrogen-burning surface layer. A fit to a white dwarf model atmosphere gives a temperature of 106K, the hottest found so far. This high temperature is consistent with a white dwarf mass of 1.3-1.4 solar mass, approaching the Chandrasekhar limit, and burning close to the nuclear stability limit.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)


Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints