The first readings from NASA's Neutron star Interior Composition Explorer (NICER) mission are in and they're already blowing astronomers' minds. For the first time ever, NICER detected a binary star system in which an X-ray pulsar is orbited by a white dwarf in only 38 minutes.
This has now become the fastest-known orbital period for this type of binary star system, NASA explains in a news release. The system in question is called IGR J17062–6143 (J17062 for short) and is located about 16,300 light-years away from our planet, Sci News reports.
Pulsars are superdense neutron stars — objects with extremely dense matter that are close to collapsing into black holes — which spin at incredible speeds and appear to pulse at Earth. The pulsar in J17062 falls into the category of accreting millisecond X-ray pulsars (AMXP), which are pulsars that emit X-rays and have a rotational period that doesn't exceed 10 milliseconds.
J17062's pulsar spins about 9,800 times per minute and shoots out X-rays with a frequency of 163 times per second. The star system was first discovered in 2006 and has been studied before with NASA's Rossi X-ray Timing Explorer, but only NICER was able to capture the record-fast orbit of J17062's stars.
"Neutron stars turn out to be truly unique nuclear physics laboratories, from a terrestrial standpoint," said NICER lead scientist Zaven Arzoumanian, an astrophysicist at NASA's Goddard Space Flight Center.
"We can't recreate the conditions on neutron stars anywhere within our solar system. One of NICER's key objectives is to study subatomic physics that isn't accessible anywhere else," he pointed out.
NICER uncovered that the superdense pulsar is orbited by a "lightweight" white dwarf, no bigger than 1.5 percent the mass of our sun, that gallops around it completing a full orbit in 38 minutes flat. By comparison, the X-ray pulsar is a lot heavier and weighs around 1.4 solar masses.
Being substantially more massive, the pulsar has a strong gravity pull that steals away material from the white dwarf and draws it into a surrounding accretion disk (pictured above). This is why the pulsar is defined as "accreting."