A silhouette of a man sitting on a rock looking up into the sky
A double star system or binary stars are two stars orbiting one common center mass. The stars are classified in two: the primary star is the brightest one (A) and the dimmer of the two is the secondary star (B). It is more than four-fifths of the single points of light that we observe in the night sky. They come in an array of configurations that help our scientists and researchers classify the stars, and could influence the development of life.
This new double star system discovered by NASA seems to have an alter ego. It is like the cosmic version of Dr. Jekyll and Mr. Hyde.
Using the Chandra X-ray and the National Science Foundation's Karl F. Jansky Very Large Array (VLA), scientists were able to spot the double star system called Terzan 5 CX1 roughly 19,000 light-years away from Earth in Terzan 5, a globular cluster.
Chandra X-ray observatory was launched on July 23, 1999, and ever since then, it became NASA's flagship mission for X-ray astronomy. It is designed to detect X-ray emissions from hot regions in the universe like clusters of galaxies, exploding stars, and matter around black holes. Chandra is managed by NASA's Marshall Space Flight Center. While the Chandra X-ray Center of the Smithsonian Astrophysical Observatory controls science and flight operations from Cambridge and Burlington, Massachusetts.
The neutron star closely orbits its lower-mass stellar companion as shown in the data collected by scientists after more than decades of observation. The Chandra detects the bright X-ray light emitted when the neutron star pulls material from the secondary star into a surrounding accretion disk.
The double stellar is then referred to as a low-mass X-ray binary at this stage. However, the stellar duo rotates and transforms into what is known as a millisecond pulsar star, which emits pulses of radio waves detected by the Very Large Array (VLA). The binary stars appear to go back to its original state after a few years.
"The neutron star can spin faster and faster until the roughly 10-mile-wide sphere, packed with more mass than the sun, is rotating hundreds of times per second," NASA officials said in a statement. "Eventually, the transfer of matter slows down and the remaining material is swept away by the whirling magnetic field of the neutron star, which becomes a millisecond pulsar."
Terzan 5 CX1 had become about ten times fainter in X-rays as shown in Chandra's data which was taken from 2009 to 2014. These results imply that the stellar duo underwent a transformation into behaving like a millisecond pulsar star and was blowing materials outward. In 2016, the Chandra observed the Terzan 5 CX1 again and it had changed back to acting like a low-mass X-ray binary again.
Astronomers need to detect radio pulses while Terzan 5 CX1 is faint in X-rays to confirm its "Jekyll and Hyde" behavioral pattern. Along with sensitive searches for pulses in existing data, scientists plan to search more X-ray and radio observations to find this behavior. So far, there are only three known and confirmed examples of these "identity-changing" systems.
Arash Bahramain of the International Center for Radio Astronomy Research (ICRAR), Australia led the study of this "Jekyll and Hyde" binary.