An amateur astronomer has just spotted a “new object” in the sky. In fact, it is a star recently transformed into a nova. And it’s still bright enough that you can see it tonight.
What is a nova?
A nova is a star that suddenly becomes very bright. This bright light only lasts a few days to a few weeks. The object then gradually resumes its initial shine.
The phenomenon occurs in a binary system made up of a white dwarf and a star in the process of becoming a red giant. The latter then loses mass in favor of the former. As a result, an accretion disk forms around the white dwarf before falling on the star.
These gases which touch the surface are then compressed and heated to temperatures of the order of tens of millions of Kelvin, until the pressures and temperatures become large enough to trigger a thermonuclear explosion. And boom: you have a nova!
A nova in the direction of Cassiopeia
On the evening of March 18, Japanese amateur astronomer Yuji Nakamura spotted one of these events, revealed by a “new point of light” in the familiar constellation Cassiopeia.
Astronomers from Kyoto University then took over using the 3.8-meter Seimei telescope atop Mount Chikurinji, Japan. They were able to obtain a spectrum of the new object cataloged as PNV J23244760 + 6111140, confirming that it was indeed a classic nova.
At the time of its discovery, the star displayed magnitude 9.6. Then, in a few hours, it would have reached a magnitude 9.1, before presenting a magnitude 7.8 the next day (March 19). Remember that the higher the magnitude, the lower the brightness. At this magnitude, the object would be bright enough to be spotted with a simple pair of binoculars.
For those interested (from the northern hemisphere only), start by identifying the familiar “W” of the constellation Cassiopeia. This structure is visible high in the northwest sky once the sun goes down. Then use the stars Schedar and Caph as benchmarks. The nova, is located approximately 5.9 ° northwest of Caph, as shown in the image below:
It is difficult to say how long this event will be visible or how bright it will be over the next few days. Your best bet, to put the odds in your favor, is to attempt this observation as quickly as possible. It’s time to take out the binoculars, or your telescope!