Discovery of new Be/X-ray binary star system

UKIDSS J-band finding chart for 4XMM J182531.5–144036. The red circle is centered on the XMM-Newton detected position, with a radius of 1′′ equal to the positional error. The white circle is centered on the Chandra detected position and has a radius of 0.6′′ equal to its positional error. Credit: arXiv (2024). DOI: 10.48550/arxiv.2401.02468

An international team of astronomers has discovered a new Be/X-ray binary star system. This was reported in an article published on the preprint server arXiv. An X-ray binary consists of an ordinary star or white dwarf that transfers mass to a compact neutron star or black hole. Based on the mass of the companion star, astronomers classify it into low-mass X-ray binaries (LMXBs) and high-mass X-ray binaries (HMXBs). The Be/X-ray system is the largest subgroup of HMXB and consists of Be stars and neutron stars, including pulsars. 4XMM J182531.5-144036 was first discovered as a hard X-ray source by the XMM-Newton satellite in April 2008. In the new study, the researchers analyzed additional data and showed that the location of the source corresponds to the location of objects that emit excess radiation in the near-infrared region. This object also has a strong hydrogen emission line. The distance to 4XMM J182531.5-144036 is estimated to be approximately 3,300 to 23,000 light years, but the exact value is not yet known. Distribution time is 250-500 days.

A Be star is a very hot spectral class B (blue-white) star with an effective temperature of 10,000 to 30,000 Kelvin and a luminosity of class III to V (i.e., not a supergiant), with at least one emission line. is characterized by. Hydrogen rules the balmer series.