Star-eating pulsar baffles scientists

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Pulsars are a special type of neutron stars. They are stellar remnants with enormous spin velocities. Seen from Earth they appear to have constant and strong changes between brightness levels, similar to pulses. There is one particular specimen that breaks this pattern and so far there has been no explanation for this difference.

ESA XMM Newton in sync pulsar 625
Illustration of the pulsar PSR J1023+0038 extracting matter from its binary system companion. Credits: ESA.

Stellar beacons

A team of researchers used data collected by twelve ground- and space-based telescopes in the most comprehensive observing campaign on the object PSR J1023+0038. This is an example of pulsar with an anomalous behaviorIt is different from others of its kind. It is part of a binary system in the constellation of the Sextant.

J1023 extracts material from its orbital companionThe Earth's temperature, causing changes in the pulses that are measured from the Earth. The gases accumulate in a disk around the pulsar in a struggle to fall gravitationally. Since the beginning of the process it changed its emission patterns, losing its beam of light and varying within two brightness modes.

In the first, also known as high mode, the pulsar shows strong X-ray, ultraviolet and visible emissions. On the other hand, in the low mode there is a clear preference for radio waves. The change between these two can last from seconds to a few minutes, accumulating a total of 280 jumps in a single day.

Observations were able to determine the cause of this strange behavior. In the second mode, part of the matter in the disk is ejected at high speed in a jet perpendicular to the orbital plane. At the same time, more material is extracted from the star, generating heat up to the point of emit electromagnetic radiation at very energetic wavelengths. Finally, it is fired rapidly, repeating the cycle in short periods of time.

Future observations will allow a better understanding of the processes and interaction between the pulsar and its orbital companion. In addition to providing valuable information on possible mechanisms that distribute the elements produced in the stars to the interstellar medium.

Francisco Andrés Forero Daza