2006/05/25 by T. W. J. Thompson, T. W. Thompson, John A. Tomsick +5 · 1 citation
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Mechanics and Biomechanics Studies #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1086/506251
published as Astrophys.J.649:373-381,2006 · Accepted for publication in ApJ; 8 pages, 8 figures
arxiv created 2006/05/25 · openalex publication_date 2006/09/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
With recent and archival Rossi X-Ray Timing Explorer ( RXTE ) X-ray measurements of the heavily obscured X-ray pulsar IGR J16393-4643, we carried out a pulse timing analysis to determine the orbital parameters. Assuming a circular orbit, we phase-connected data spanning over 1.5 yr. The most likely orbital solution has a projected semimajor axis of 43 ± 2 lt-s and an orbital period of 3.6875 ± 0.0006 days. This implies a mass function of 6.5 ± 1.1 M ☉ and confirms that this INTEGRAL source is a high-mass X-ray binary (HMXB) system. By including eccentricity in the orbital model, we find e < 0.25 at the 2 σ level. The 3.7 day orbital period and the previously known ~910 s pulse period place the system in the region of the Corbet diagram populated by supergiant wind accretors, and the low eccentricity is also consistent with this type of system. Finally, it should be noted that although the 3.7 day solution is the most likely one, we cannot completely rule out two other solutions with orbital periods of 50.2 and 8.1 days.