Micronovae

The star system TV Columbae has perplexed astronomers for decades. It flares up, getting about 30 times brighter than average. After a few hours, it returns to normal. And that cycle has been hard to explain. But recent studies have offered a possible solution: a micronova.

TV Columbae is more than 1600 light-years away. It’s in the constellation Columba, the dove, which is too far south to see from most of the U.S.

The system consists of two stars. One is in the prime of life. The other is a white dwarf — the corpse of a once-normal star. It’s heavy but tiny — no bigger than Earth. The two stars may be less than a million miles apart. That’s close enough for the powerful gravity of the white dwarf to “steal” gas from its companion. The gas then piles up on the surface of the white dwarf.

The same thing happens in many other star systems. In those cases, the gas spreads across the entire surface of the white dwarf. And if the gas gets hot enough, it triggers a powerful explosion — a nova. That can make the system shine many thousands of times brighter than average.

The new studies suggest that something similar happens on TV Columbae and a few other stars. Instead of spreading across the entire white dwarf, though, the gas is concentrated in columns at the stars’ magnetic poles. The gas gets hot enough to explode, but there’s much less of it. So that triggers a smaller but still-mighty eruption: a micronova.
 

Script by Damond Benningfield