Bright Supernova in M82

Supernova 2014J has brightened to 11th magnitude in M82 off the Big Dipper. It's visible in amateur telescopes during evening.

Supernova in Messier 82
The supernova in M82 as imaged by Leonid Elenin (Lyubertsy, Russia) and I. Molotov (Moscow, Russia) on Jan. 22.396. It's located at right ascension 9h 55m 42.2s, declination +69° 40′ 26″. It was V magnitude 11.7 at the time.
Leonid Elenin
A surprise supernova has erupted in M82, the famous nearby irregular galaxy in Ursa Major. Observers are reporting it at about magnitude 11.3 as of Thursday, January 23rd, with a color on the orange side of white.

A spectrum reported by Yi Cao and colleagues (Caltech) suggests that it may still be two weeks away from reaching its peak brightness. Spectra show it to be a Type Ia supernova — an exploded white dwarf — with debris expanding at 20,000 kilometers per second. It is reddened, and hence must also be dimmed, by dust in M82 along our line of sight.

Supernova in Messier 82
Before and after. The supernova image, taken remotely by Ernesto Guido, Nick Howes, and Martino Nicolini on January 22.3, shows the exploded star at unfiltered CCD magnitude 11.3. Their website.
Ernesto Guido / Nick Howes / Martino Nicolini
M82 is a near neighbor as galaxies go, at a distance of 11 or 12 million light-years. It's a favorite for amateur astronomers and researchers alike, with its thick dust bands, sprays of gas, and bright center undergoing massive star formation. The supernova is not in the central star-forming region but off to one side, 58 arcseconds to the west-southwest.

Remarkably, the supernova went undiscovered for a week as it brightened. Prediscovery unfiltered CCD images by K. Itagaki of Yamagata, Japan, show nothing at its location to as faint as magnitude 17.0 through January 14.5. But on January 15.57 is was magnitude 14.4; on January 16.64 it was 13.9; on January 17.61, 13.3; January 19.62, 12.2; and January 20.62, 11.9. Images.

The M81-M82 galaxy pair, 2/3° apart, lie in a dim region of Ursa Major off the Big Dipper. They're detectable in a large finderscope in a dark sky. Once you've recognized the general area, you'll probably need this more detailed chart.
M82 is well up in the northeastern sky by 7 or 8 p.m. (for observers at mid-northern latitudes). The waning Moon doesn't rise until much later.

The new point of light received the name Supernova 2014J once its nature was confirmed. It originally went by the preliminary designation PSN J09554214+6940260.

Here's a comparison-star chart from the American Association of Variable Star Observers (AAVSO). North is up, east is left, the chart is 1° wide, and stars are plotted to magnitude 13.5. If you want other parameters, or if the link fails, make your own chart using the AAVSO Variable Star Plotter. For the star name enter SN 2014J. The chart does not plot the galaxy.

And here's a preliminary AAVSO light curve.

Supernova in M82
S&T senior editor Dennis di Cicco captured M82's supernova on the evening of January 22nd with an Officina Stellare 12-inch f/7.9 RiDK 305 astrograph. Although it was clear, frigidly cold (below zero F) temperatures contributed to the relatively poor seeing.
S&T: Dennis di Cicco & Sean Walker

A Flukey Find

The first people to recognize the supernova were a group of students — Ben Cooke, Tom Wright, Matthew Wilde and Guy Pollack, assisted by teaching fellow Stephen J. Fossey — taking a quick image at the University College London Observatory (within the London city limits!) on the evening of January 21st, at 19:20 UT.

"The discovery was a fluke," says a university press release, "a 10-minute telescope workshop for undergraduate students that led to a global scramble to acquire confirming images and spectra.

" 'The weather was closing in, with increasing cloud,” Fossey says. 'So instead of the planned practical astronomy class, I gave the students an introductory demonstration of how to use the CCD camera on one of the observatory’s automated 0.35-meter telescopes.'

"The students chose M82, a bright and photogenic galaxy, as their target, as it was in one of the shrinking patches of clear sky. While adjusting the telescope’s position, Fossey noticed a star overlaid on the galaxy which he did not recognise from previous observations.

"They inspected online archive images of the galaxy, and it became apparent that there was indeed a new starlike object in M82. With clouds closing in, they switched to taking a rapid series of 1- and 2-minute exposures through different colour filters to check that the object persisted, and to be able to measure its brightness and colour."

The original press release, and the BBC repeating it, claimed that this is the nearest supernova since Supernova 1987A in the Large Magellanic Cloud. In fact SN 1993J in M81 was at essentially the same distance within the uncertainties, and two subsequent supernovae, SN 2004am and SN 2008iz (an obscured radio supernova), occurred within M82 itself.

Watch here for updates.

Posted by Alan MacRobert, January 22, 2014

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