SN 2022hrs

A Supernova in Galaxy NGC 4647 in Virgo

Image exposure:
25 minutes
Image field of view:
23.9 x 16 arcmin
Image date:

On 16th April, April 2022 a large star blew itself into oblivion.

Or to be more accurate, the light from the explosion finally brought us the news of an explosion which occurred 57 million years ago, during the Eocene Era, when the land mass of Earth was covered from pole to pole by forests.

In the image: to the left is a massive elliptical galaxy known as Messier 60. On the right is a smaller and more distant spiral galaxy called NGC 4647.

In between them is the supernova, a bright dot, located in the the spiral arms of NGC 4647. The supernova outshines it’s host galaxy and is comparable in apparent brightness to the much closer stars in our own galaxy.

The supernova has been designated SN 2022hrs.

SN” stands for supernova; “2022” for the year of discovery; and “hrs” is an alphabetical numbering system designed to confuse everyone except the smart person who dreamed it up. It might mean the 695th supernova of the year – but don’t quote me.

Astronomers always like to be a bit different.

My image was taken 17 days after the initial discovery. The supernova that you see in the picture wasn’t there prior to 16th April 2022 and it will only be visible for a few more weeks.

It is a type 1a supernova, which means it began with a white dwarf star and a red giant star in a close binary orbit around each other. When they got too close, the more dense white dwarf attracted gas from the red giant. Over time, enough matter was transferred to the white dwarf for it to reach a critical mass (about 1.4 times the mass of the Sun), nothing could save it. Reignited nuclear reactions triggered a catastrophic explosion. A supernova.

M60 is 57 million light-years away and astronomers have noticed signs of tidal interactions which indicate that NGC 4647 is at a similar distance. There is a faint galaxy towards the left, called LEDA 42846, a member of the same cluster of galaxies.

Telescope:Meade LX-90 200mm Schmidt-Cassegrain
(deforked); 2000 mm f/l @ f/10.
Optics:Astronomik light pollution filter.
Mount & Guiding:SkyWatcher EQ6-R Pro mount.
Imaging camera:ZWO ASI 071 MC cooled.
Cosmic Focus Observatory34° South (on my front driveway)

Images © Roger Powell
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  1. Amazing, 57M ly away and we see basically a single star. (Or maybe you could say the effects of two.) Also amazing, that we have a way to determine that the earlier condition was a binary, white dwarf ad red giant. I wonder whether the red giant was close enough to have been destroyed. It seems that once the supernova residue light fades, we will not be able to tell much at all.

    Liked by 1 person

    1. At that distance it would be difficult to locate the star – but who knows what can be achieved using Webb and Hubble Space Telescopes.

      I too have wondered about the effect on the red giant. It was already surrendering its outer envelope to the white dwarf but must have been severely disrupted during the blast.

      I’ve not seen the research on this but I would speculate that with the white dwarf likely to have transformed into a neutron star or black hole, it might continue sucking layers off the red giant. If that’s the case, it would likely speed up its destiny of becoming a white dwarf itself. Then, in a few billion years they could both merge.

      Let’s hope we get a Milky Way supernova soon.

      Liked by 1 person

      1. In a Type 1a supernova the white dwarf explosively detonates, when its hits a critical mass. Enough energy is released to , completely destroy the star.
        There is no black hole of neutron star remnant

        Liked by 1 person

        1. That’s interesting. Thanks Steve, I didn’t know that but it makes sense, being such a small object. I’d still like to know what happens to the poor old red giant.


  2. I’m curious about this statement: “…it will only be visible for a few more weeks.”

    How do we know this? I thought some lasted months. Rather, the event might be quick, but the observable light might last months. I can’t remember which Chinese-observed SN lasted nearly three months.


    1. It all depends on the definition of “visible” and the instruments used.

      I estimate the magnitude of the supernova in my image a bit dimmer than the 11.8 magnitude star above it, so about 12th magnitude. Nowhere near naked eye visibility. It’s probably reaching a peak about now, three weeks after detonation. So from now it is likely to begin to dim, slowly at first, then faster – but not as rapidly as it rose.

      When will it disappear from the view of my own instruments? I’m not a physicist but I wouldn’t expect to see much after about 10-15 weeks.

      The Chinese supernova you allude to was probably SN1054, believed to be a Type II supernova. It was a local event in the Milky Way, only 6,500 light years away. They estimated it peaked at about magnitude -6, many times brighter than Venus, easily visible in daylight and recorded as lasting 642 days overall.


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