From Sky & Telescope: “Supernova Discovered in the Bright Galaxy Messier 77”

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From Sky & Telescope

November 29, 2018
Bob King

A new supernova in the bright galaxy Messier 77 in Cetus is within range of amateur telescopes. Here’s how to find it.

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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 Messier 77, 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, Messier 77 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.

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Use this map to locate Delta Ceti and the supernova host galaxy, Messier 77. 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. Stellarium

This is the first recorded supernova in Messier 77 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.

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“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

Messier 77 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 Messier 77 on the opposite side less than a degree to the southeast.

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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.

See the full article here .

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Sky & Telescope magazine, founded in 1941 by Charles A. Federer Jr. and Helen Spence Federer, has the largest, most experienced staff of any astronomy magazine in the world. Its editors are virtually all amateur or professional astronomers, and every one has built a telescope, written a book, done original research, developed a new product, or otherwise distinguished him or herself.

Sky & Telescope magazine, now in its eighth decade, came about because of some happy accidents. Its earliest known ancestor was a four-page bulletin called The Amateur Astronomer, which was begun in 1929 by the Amateur Astronomers Association in New York City. Then, in 1935, the American Museum of Natural History opened its Hayden Planetarium and began to issue a monthly bulletin that became a full-size magazine called The Sky within a year. Under the editorship of Hans Christian Adamson, The Sky featured large illustrations and articles from astronomers all over the globe. It immediately absorbed The Amateur Astronomer.

Despite initial success, by 1939 the planetarium found itself unable to continue financial support of The Sky. Charles A. Federer, who would become the dominant force behind Sky & Telescope, was then working as a lecturer at the planetarium. He was asked to take over publishing The Sky. Federer agreed and started an independent publishing corporation in New York.

“Our first issue came out in January 1940,” he noted. “We dropped from 32 to 24 pages, used cheaper quality paper…but editorially we further defined the departments and tried to squeeze as much information as possible between the covers.” Federer was The Sky’s editor, and his wife, Helen, served as managing editor. In that January 1940 issue, they stated their goal: “We shall try to make the magazine meet the needs of amateur astronomy, so that amateur astronomers will come to regard it as essential to their pursuit, and professionals to consider it a worthwhile medium in which to bring their work before the public.”