2003/01/31 by Michael J. Stark, Malinda Saia · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #astro-ph
paper · pdf · doi:10.1086/375287
published as Astrophys.J. 587 (2003) L101 · 7 pages, 3 figures, Accepted for publication in The Astrophysical Journal Letters
arxiv created 2003/03/13 · openalex publication_date 2003/03/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We measured Doppler shifts of three bright spectral lines in the X-ray emission from Cygnus X-3 as recorded by the Chandra X-Ray Observatory . Doppler shifts of lines associated with Si XIV and S XVI exhibit orbital modulation. The magnitude and phasing of this modulation relative to the orbital ephemeris indicate the location of the source of this emission within the wind emanating from the compact object's companion. These observations enable us to make an indirect measurement of the separation of the two stars. Under certain assumptions our observation of a line associated with Fe XXV also limits the mass of the compact object M C ≤ 3.6 M ☉ .