During the time it has been in service, the W.M. Keck Observatory in Hawaii has made some fascinating discoveries in the night sky on its exploration of the universe. Astronomers at the observatory have announced that they have come closer to understanding a phenomenon that appeared in the northern sky this summer. The phenomena was dubbed AT2018cow and is known a “The Cow” for short.
The team at the Keck Observatory worked with the University of Hawaii Institute for Astronomy and its ATLAS twin telescopes to investigate The Cow. The group has gathered evidence that says that The Cow is likely evidence of the exact moment a star collapsed to form a compact object such as a black hole or neutron star. The debris left from that collapse is swirling around the event horizon of the object and caused the very bright glow seen in the summer sky.
The team says that the rare event has allowed astronomers to better understand the physics during the first moments of the creation of a black hole or neutron star. This is the first time such a phenomenon has been viewed. Lead paper author Raffaella Margutti says that based on X-ray and UV emissions, The Cow may have been caused by a black hole as it swallowed up a white dwarf star. Further investigation made the team believe that The Cow was instead the formation of an accreting black hole or neutron star.
Margutti noted that science has known from theory that when a star dies it forms either a black hole or neutron star, but neither had ever been observed right after they are born. The Cow was first spotted on June 16 after the ATLAS telescope captured an extremely bright anomaly 200 million light-years away in the Hercules constellation. The object flared up quickly and then disappeared almost as fast.
The scientists say that the anomaly was unusually bright at 10-100 times brighter than a typical supernova. It also flared and disappeared much faster than other known star explosions; within 16 days the object had emitted most of its power, and the object had very little ejecta swirling around. The lack of ejecta allowed the team to peer at its core and deduce that a black hole or neutron star was in the center of the mystery.