2005/10/13 by P. Mucciarelli, L. Zampieri, R. Falomo +2 · 28 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Binary number #Galaxies: Formation, Evolution, Phenomena #Hubble sequence #Main sequence #Photometry (optics) #Star (game theory) #Stars #Supergiant #Very Large Telescope #astro-ph
paper · pdf · doi:10.1086/498448
published in The Astrophysical Journal 633(2), L101-L104 (IOP Publishing) · 7 pages, 4 figures, accepted for publication in ApJ Letters
arxiv created 2005/10/13 · openalex publication_date 2005/10/31 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We present archive ESO VLT photometric and spectroscopic data of the ultraluminous X-ray source NGC 1313 X-2. The superb quality of the VLT images reveals that two distinct objects, with R magnitudes 23.7 and 23.6, are visible inside the Chandra error box. The two objects, separated by 0 75, were unresolved in our previous ESO 3.6 m+EFOSC image. We show that both are stars in NGC 1313, the first a B0-O9 main-sequence star of ~20 M ☉ , the second a G supergiant of ~10 M ☉ . Irrespective of which of the two objects the actual counterpart is, this implies that NGC 1313 X-2 is a high-mass X-ray binary with a very massive donor.