2005/01/31 by N. Ivanova, Natalia Ivanova, F. A. Rasio +5 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Cluster (spacecraft) #Gamma-ray bursts and supernovae #Globular cluster #Neutron star #Physics #Pulsars and Gravitational Waves Research #Star cluster #Stars #White dwarf #X-ray binary #astro-ph
paper · pdf · doi:10.1086/429220
published as Astrophys.J. 621 (2005) L109-L112 · 4 pages, 1 figure, in emulateapj style. ApJ Letters, in press, includes corrections in proofs
openalex publication_date 2005/02/09 · arxiv created 2005/02/10 · arxiv updated 2012/08/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Bright, ultracompact X-ray binaries observed in dense star clusters, such as Galactic globular clusters, must have formed relatively recently, since their lifetimes as persistent bright sources are short (e.g., ~10 8 yr above 10 36 ergs s -1 for a 1.4 M ☉ neutron star accreting from a degenerate helium companion with an initial mass of ~0.2 M ☉ ). Therefore, we can use the present conditions in a cluster core to study possible dynamical formation processes for these sources. Here we show that direct physical collisions between neutron stars and red giants can provide a sufficient formation rate to explain the observed numbers of bright sources. These collisions produce tight, eccentric neutron star-white dwarf binaries that decay to contact by gravitational radiation on timescales ~10 6 -10 10 yr, usually shorter and often much shorter than the cluster age.