Black Widow pulsar

Description

The prevailing theoretical explanation for the system implied that the companion is being destroyed by the strong powerful outflows, or winds, of high-energy particles caused by the neutron star; thus, the sobriquet black widow pulsar was applied to the object. Subsequent to this, other objects with similar features have been discovered, and the name has been applied to the class of millisecond pulsars with an ablating companion, as of February 2023 around 41 black widows are known to exist.

Later observations of the object showed a bow shock in H-alpha and a smaller-in-extent shock seen in X-rays (as observed by the Chandra X-ray Observatory), indicating a forward velocity of approximately a million kilometers per hour.

In 2010, it was estimated that the neutron star's mass was at least ${\displaystyle 1.66M_{\odot }}$ and possibly as high as ${\displaystyle 2.4M_{\odot }}$ (the latter of which, if true, would surpass PSR J0740+6620 for the title of most massive neutron star yet detected and place it within range of the Tolman–Oppenheimer–Volkoff limit). In January 2023 the upper limit was revised down to ${\displaystyle 1.8M_{\odot }}$