NASA’s NICER Mission Finds an X-ray Pulsar in a Record-fast Orbit

Scientists analyzing the first data from the Neutron star Interior Composition Explorer (NICER) mission have found two stars that revolve around each other every 38 minutes — about the time it takes to stream a TV drama. One of the stars in the system, called IGR J17062–6143 (J17062 for short), is a rapidly spinning, superdense star called a pulsar. The discovery bestows the stellar pair with the record for the shortest-known orbital period for a certain class of pulsar binary system.

The data from NICER also show J17062’s stars are only about 186,000 miles (300,000 kilometers) apart, less than the distance between Earth and the Moon. Based on the pair’s breakneck orbital period and separation, scientists involved in a new study of the system think the second star is a hydrogen-poor white dwarf.

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The researchers were also able to determine that J17062's stars revolve around each other in a circular orbit, which is common for this type of system. The white dwarf donor star is a "lightweight," only around 1.5 percent of our Sun's mass. The pulsar is much heavier, around 1.4 solar masses.

The stars orbit a point around 1,900 miles (3,000 km) from the pulsar, almost as if the donor star orbits a stationary neutron star, but NICER can is sensitive enough to detect a slight fluctuation in the neutron star's X-ray emission due to the tug from the donor star.

The Neutron Star Interior Composition Explorer (NICER) payload, destined for the exterior of the space station, will study the physics of neutron stars, providing new insight into their nature and behavior. These stars are called 'pulsars' because of the unique way they emit light – in a beam similar to a lighthouse beacon. As the star spins, the light sweeps past us, making it appear as if the star is pulsing. Neutron stars emit X-ray radiation, enabling the NICER technology to observe and record information about their structure, dynamics and energetics.

The payload also includes a technology demonstration called the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) which will help researchers to develop a pulsar-based space navigation system.

Scientists have found evidence of the dimmest and coldest white dwarf ever detected.

According to NASA, a white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel.

Scientists have possibly found evidence of the dimmest and coldest white dwarf star ever detected.

This one, being an estimated 11 billion years old, is below the visibility range of even the best optics.