A pulsar-helium star compact binary system formed by common envelope evolution

• DOI: 10.1126/science.ado0769
• Publication Date: 2025-05-23T12:53:09Z
• Authors: Z. L. Yang; J. L. Han; D. J. Zhou; W. C. Jing; W. C. Chen; T. Wang; X. D. Li; S. Wang; B. Wang; H. W. Ge; Y. L. Guo; L. H. Li; Y. Shao; J. F. Liu; W. Q. Su; L. G. Hou; W. J. Huang; J. C. Jiang; P. Jiang; J. H. Sun; B. J. Wang; C. Wang; H. G. Wang; J. B. Wang; N. Wang; P. F. Wang; S. Q. Wang; H. Xu; J. Xu; R. X. Xu; W. M. Yan; Y. Yan; X. P. You; D. J. Yu; Z. S. Yuan; C. F. Zhang
• Keywords: Common envelope; Orbital period; Orbit (dynamics); X-ray pulsar; Star (game theory); Envelope (radar); Roche lobe; Compact star; X-ray binary

A stellar common envelope occurs in a binary system when the atmosphere of an evolving star expands to encompass orbiting companion object. Such systems are predicted evolve rapidly, ejecting and leaving tighter orbit around stripped star. We used radio timing identify pulsar, PSR J1928+1815, with spin period 10.55 ms compact orbital 3.60 hours. The has 1.0 1.6 solar masses, eclipses pulsar for about 17% orbit, is undetected at other wavelengths, so it most likely helium interpret this as having recently undergone phase, producing binary.