2005/06/21 by Michael T. Wolff, M. T. Wolff, Peter A. Becker +3 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Eddington luminosity #Flux (metallurgy) #Gamma-ray bursts and supernovae #Low Mass #Luminosity #Neutron star #Photosphere #Physics #Pulsars and Gravitational Waves Research #RADIUS #Spectral line #X-ray binary #astro-ph
paper · pdf · doi:10.1086/444348
published as Astrophys.J.632:1099-1103,2005 · 15 pages including 2 figures and 1 table. Accepted for publication in the Astrophysical Journal
arxiv created 2005/06/21 · openalex publication_date 2005/10/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We have observed an unusually strong X-ray burst as a part of our regular eclipse timing observations of the low-mass binary system EXO 0748-676. The burst peak flux was 5.2 × 10 -8 ergs cm -2 s -1 , approximately 5 times the normal peak X-ray burst flux observed from this source by RXTE . Spectral fits to the data strongly suggest that photospheric radius expansion occurred during the burst. In this paper we examine the properties of this X-ray burst, which is the first example of a radius expansion burst from EXO 0748-676 observed by RXTE . We find no evidence for coherent burst oscillations. Assuming that the peak burst luminosity is the Eddington luminosity for a 1.4 M ☉ neutron star, we derive a distance to EXO 0748-676 of 7.7 kpc for a helium-dominated burst photosphere and 5.9 kpc for a hydrogen-dominated burst photosphere.