New Class of Supernova Designated ‘Cow’

Jan 12, 2022 | AAS, Daily Space, Supernovae

New Class of Supernova Designated ‘Cow’
IMAGE: Artwork comparing a normal supernova to a Cow-like supernova. CREDIT: Bill Saxton, NRAO/AUI/NSF

Folks, listen to Beth when she says you shouldn’t let astronomers name things. We do terrible terrible things.

For instance, in 2018 a star exploded, and a predetermined way to name things meant that glorious object was named AT2018cow, and c-o-w spells ‘cow’, and now, I kid you not, since that particular exploding star was the first of a newly identified type of exploding star, these supernovae are called Cow supernovae.

Astronomers can do many things well. Naming is not one of them.

What makes Cows unique is their short-lived brightness. These stellar explosions are ten times brigher than typical supernovae, fad much more quickly, and also flicker in X-rays. Early analysis hinted these events may be massive stars transitioning into black holes or neutron stars in their deaths.

Now, a total of five objects have been found, with the latest event, AT2020mrf, being published in a new paper in The Astrophysical Journal with first author Yuhan Yao. This latest event is also the brightest to date, and Yao explains: The large amount of energy released and the fast X-ray variability seen in AT2020mrf provide strong evidence that the nature of the central engine is either a very active black hole or a rapidly spinning neutron star called a magnetar. In Cow-like events, we still don’t know why the central engine is so active, but it probably has something to do with the type of the progenitor star being different from normal explosions.”

The more we look up, the more weird and rare things we have the chance to find, and these terribly named objects are my new favorite things to watch the research on.

More Information

Caltech press release

“The X-ray and Radio Loud Fast Blue Optical Transient AT2020mrf: Implications for an Emerging Class of Engine-Driven Massive Star Explosions,” Yuhan Yao et al., submitted to The Astrophysical Journal (preprint on


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