User:Jaciskow/Black Widow Pulsar

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Background

The Black Widow Pulsar (PSR B1957+20) is an eclipsing binary millisecond pulsar in the Milky Way. Discovered in 1988, it is located roughly 6,500 light-years away from Earth. It orbits with a brown dwarf or Super-Jupiter companion with a period of 9.2 hours with an eclipse duration of approximately 20 minutes. When it was discovered it was the first such pulsar known. 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, and so the sobriquet black widow 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.

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 Space Telescope), 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 $1.66M_{\odot }$, and possibly as high as $2.4M_{\odot }$ (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).

A "Discrete Devourer"

Previously, due to its innate affinity of consuming its companion star while rotating at an immense speed, the most reliable way to identify a spider binary was by measuring the gamma ray, X-Ray, and radio wave emissions produced by a millisecond pulsar while its partner star orbits around it. However, a recently discovered black widow candidate, ZTF J1406+1222, is proving to be an outlier among the common consensus, since it has failed to provide the expected readings from any of the aforementioned measurements. Instead, thanks to the support of the Zwicky Transient Facility, scientists and researchers have been able to utilize exclusive optical photons capable of quantifying relevant data when classifying types of pulsars from light alone. They found ZTF J1406+1222 to have a 62 minute orbital period, with an immense amplitude, a rapid flux modulation, and a luminosity value within a range of 1.16 * 10³⁴ and 1.37 * 10³⁴ erg/s. These sets of data is indictive specifically to inner spider binaries because of the speed of the orbit and the rate at which the brightness of the outer companion changes. However the distinction between the two subgroups of spider binaries, black widows and redbacks, is made through the relative size of the said companion star. Specifically, black widow pulsars drain stars that are relatively smaller when compared to those drained by redback pulsars. In the case of ZTF J1406+1222, the companion star is a most likely a super compact white dwarf, which if accurate, would simultaneously be the most compact white dwarf to date. But regardless, that binary is not alone in the orbit. A late K-type cool subdwarf is stuck with them, orbiting within the Galactic Halo. This conclusion was derived from the hydrogen absorption lines seen during the orbital phase and images seen through HiPERCAM, Gaia eDR3, Pan-STARRS1, and Sloan Digital Sky Survey. In fact, through this same observational sequence, they were able to deduce the binary's proper motion, which they then figured the total age out to be approximately several billions of years old. However, this proper motion revelation brought about more questions than answers. The binary proved to be held within a halo orbit, which, in turn rules out the likelihood that there was any kind of pulsar kick that sent the system flying from the Galactic Centre. In addition to that, any noteworthy kick from anywhere would have more likely resulted in the system being ejected away from their cool subdwarf friend. That said, although theories about the system's origin exist, the truth remains unclear, along with the reason why a neutron star is refusing to give off any gamma ray, X-ray, or radio wave emission. But, aside from those two inquires, the data collected points to the binary system as either being classified as a new kind of black widow binary, or something else entirely.