A new supernova in the bright galaxy M77 in Cetus is within range of amateur telescopes. Here's how to find it.

Supergiant blowout in M77
New supernova 2018 ivc recently appeared in the bright Messier galaxy M77 located in Cetus at R.A. 2h 42′ 41″, Dec. -00° 00′ 48″. The object is northeast of the core along the edge of the bright inner disk.
Koichi Itagaki

On November 24th, the DLT40 Survey picked up a 15th magnitude supernova in M77, a bright, barred spiral galaxy in Cetus located 50′ southeast of 4th magnitude Delta Ceti. Whenever a supernova is discovered in a Messier galaxy, I get excited. Messiers are among the closer and brighter galaxies and often host supernovae visible in smaller telescopes.

With an apparent magnitude of 9.6, M77 is easy to find in telescopes as small as 3 inches though a 10-inch or larger scope will be needed to ferret out this supernova — at least at the moment.

Designated 2018 ivc, the new supernova has brightened to about magnitude 14.5 and appears as a tiny pinprick of light 8.7″ east and 16.1″ north of the center of the galaxy along the edge of the bright inner disk. Spectroscopy reveals the "new star" as a Type II supernova in its early stages, implying that the object could brighten further. Not to throw water on the fire, but intervening dust within the galaxy has dimmed and reddened the explosion, so it's difficult to predict how bright it might become. One outlier observation from November 25th put it at about magnitude 13.6.

Sky map showing location of host galaxy M77
Use this map to locate Delta Ceti and the supernova host galaxy, M77. While you're in the neighborhood, take a look at the variable star Mira, now rising toward maximum with a current magnitude of about 4.0.

This is the first recorded supernova in M77 and though it looks like little more than a faint star in a telescope, the reality is we're witnessing the collapse and explosion of a highly evolved supergiant star. As you read this, debris from the blast is expanding outward at some 13,500 kilometers per second (30.2 million mph). For perspective, that's a little more than one Earth-diameter per second! Going along for the ride are the complex elements that were forged in the star's core and now released into space to seed future generations of stars and their planetary systems.

Image of M77 with location of supernova marked
I've marked 2018 ivc's location with a cross in this photograph taken by the Hubble Space Telescope. You can see the object is situated within the galaxy's dusty inner arms.
NASA / ESA / A. van der Hoeven

M77 lies 47 million light-years from Earth in Cetus. After all those years of travel, how fortunate that the light from the supernova arrived just in time to track it down without a bright moon and the galaxy well-placed for viewing during evening hours. To find it, start with Menkar (magnitude 2.5), the second brightest star in Cetus, and slide about 2° to the southwest to Delta (δ) Ceti. Set Delta off to one side of the low-magnification field of view and you should see M77 on the opposite side less than a degree to the southeast.

Farewell Blast
In a Type II supernova, an aging supergiant star runs out of nuclear fuel to burn in its core, causing a sudden collapse and rebound that rips the star apart. Some Type II events leave a neutron star or black hole remnant.
NASA / CXC /M.Weiss

To dig out the stellar cinder I recommend increasing the magnification to 200x or higher and studying the location along the bright, inner disk for a stellar point — this will be the supernova. Never fear magnification — you may need to go north of 300x depending on whether 2018 ivc brightens further or not. If seeing is poor, it can be difficult to suss out the star in a bright, galactic environment. Try again on another night.

Coincidentally, the bright comet 46P/Wirtanen passes about 7° southeast of the galaxy on the nights of December 8th and 9th.

For updates, head over to David Bishop's excellent Latest Supernovae page and click on the 2018 ivc link. I'll also update this blog with additional information including my own observation of the supernova which I hope to make tomorrow night.

UPDATE Dec. 4: I finally had clear skies last night (Dec. 4.1 UT) and looked for the supernova. Unfortunately, it was still very faint — I glimpsed it several times at ~magnitude 15.0. Despite some estimates around magnitude 13, I don't believe this object ever brightened beyond ~14.5 magnitude. Normally, a supernova this close would have been an easy mark, but as described above, dust within the host galaxy likely contributed to its faintness.


M77 supernova


Image of Tom-Reiland


December 3, 2018 at 12:23 am

It appears that most of us will not be able to observe the Supernova in M77. The current magnitude is listed at 15.2 mag or fainter on some pages. I made an attempt tonight using the 21" Reflector at Wagman Observatory tonight and there was not a hint of it as I was using 127X, 282X and 462X. I have my doubts that I would have be able to see it when it was at 14.5 magnitude because of the poor seeing tonight and its closeness to the nucleus. Also, the images I saw on various pages made me question some of the estimates of the brightness of the SN. There hasn't been a SN bright enough to see in amateur scopes up to 21" since March of this year.

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Image of Bob King

Bob King

December 3, 2018 at 10:39 am

Hi Tom,
Thank you for sharing this observation. I had hoped to see it, but our forecast for clear skies turned cloudy, and it's been overcast since. When I saw one and then two ~13 mag. estimates I was suspect, the reason I chose the more conservative estimates that put the SN around 14.5. Also, based on the appearance of the object in the photographs, it looked closer to 14.5. My hope was that given it was caught on the rise, it would brighten into easy reach. We'll have to see ...

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Image of Joe Stieber

Joe Stieber

December 6, 2018 at 3:46 am

I was out to the New Jersey Pines on Tuesday night, 04-December-2018, mainly to look at comet 46P/Wirtanen, but I also looked for 2018ivc while there. With my 12.5-inch Newtonian, M77 was an easy target, but I saw no hint of the SN using up to 338x. Note that the seeing wasn’t so good.

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