NASA’s NICER mission has disclosed two stars spinning one around the other one every 38 minutes, the shortest orbital timeframe ever recorded for the specific class of binary pulsar system. Astronomically known as IGR J17062-6143, this system contains one star that is a super-dense, fast-spinning star, a so-called X-ray pulsar.
The NICER dataset also indicates that the stars of J17062 are just approximately 300,000 kilometers apart, which is shorter than the distance between the Earth and the Moon. The scientists implicated in a new study of the system are convinced that the second star is a hydrogen-poor white dwarf, because of the precipitous orbiting and separation periods.
“It is not possible that a hydrogen-rich star, like our Sun, to be the pulsar’s companion. You can’t place a star like that in such a small orbit,” explained Tod Strohmayer from the NASA Goddard and the leasing study’s author.
NASA’s NICER was able to depict the subtle emission oscillations of the X-ray pulsar
The scientists were successful in identifying that the IGR J17062-6143 stars spin one around the other in a circular orbit, that is common for accreting millisecond X-Ray pulsars.
The white dwarf star is light-weight, having only around 1.5% of the mass of our Sun, while the pulsar is significantly heavier, being of about 1.4 solar masses, implying that the stars orbit around 300,000 kilometers away from the pulsar. Strohmayer said it’s pretty much as if the white dwarf star was orbiting a static pulsar but NICER was sufficiently susceptible to detect a subtle oscillation in the X-ray output of the pulsar caused by the donor star’s pull.
“The distance between us and the X-Ray pulsar is not constant. It varies according to this orbital movement. When the pulsar is closer, the X-ray emission takes a little less time to reach us than when it is farther away. This delay time is small, only about 8 milliseconds for the J17062 orbit, but it is within the capabilities of a sensitive pulsar machine like NASA’s NICER,” said Tod Strohmayer.