The Likely Orbital Period of the Ultracompact Low-Mass X-Ray Binary 2S 0918-549

  title={The Likely Orbital Period of the Ultracompact Low-Mass X-Ray Binary 2S 0918-549},
  author={Jing Zhong and Zhongxiang Wang},
  journal={arXiv: High Energy Astrophysical Phenomena},
We report the discovery of the likely orbital period of the ultracompact low-mass X-ray binary (LMXB) 2S 0918-549. Using time-resolved optical photometry carried out with the 8-m Gemini South Telescope, we obtained a 2.4-hr long, Sloan r' light curve of 2S 0918-549 and found a periodic, sinusoidal modulation at 17.4+/-0.1 min with a semiamplitude of 0.015+/-0.002 mag, which we identify as the binary period. In addition to 4U 0513-40 in the globular cluster NGC 1851 and the Galactic disk source… Expand

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