Like one of those famous exploding cigars in a Groucho Marx movie, nature imitates life by producing an exploding cigar of its own – a brand new, bright supernova in the “Cigar Galaxy” M82 in the Great Bear. It was discovered only last night by astronomer S. J. Fossey at magnitude 11.7. Very bright!
Even a 3-inch telescope under a dark sky can snare this one. While there have been brighter supernovae – and who knows, this one may very well get brighter yet – this is the brightest, closest supernova since SN 1993J popped off in neighboring galaxy M81.
M82 goes by the nickname the Cigar Galaxy from its highly elongated shape. Through a small telescope it looks like a ghostly streak of light. At just 12 million light years from Earth it’s one of the closer galaxies to our home, making it bright enough to see in binoculars. Through a telecope, M82 is closely accompanied by the equally bright galaxy M81. Together they’re a favorite target on winter and spring nights for beginning and amateur astronomers.
The big surprise is that no one found the object sooner. Most supernovae are spotted either by professional survey programs or amateur versions of the same when they’re around 15th magnitude or fainter. Not this one. It was brighter than 12th magnitude at discovery, but had someone been looking, it was easily visible in amateur instruments as early as January 16 at magnitude 13.9, brightening to 13.3 on the 17th and 12.2 on the 19th. Yikes! Why wasn’t I out looking at this galaxy?
The new supernova, with the temporary name of PSN J09554214+6940260, is a Type Ia explosion. In plain English, what we’re witnessing back here from our cozy homes on Earth is the complete annihilation of a super compact planet-size star called a white dwarf. Before anyone knew the star would explode, it spent millenia gravitationally siphoning off gas from a very close companion star. That material accumulated on its sizzling surface, adding to the weight of the little star. When the star reached the ultimate limit of 1.4 times the mass of the sun, it imploded under its own weight, heated up to billions of degrees and burned explosively. Boom! A supernova was born.
I know that the cold won’t keep you from wanting to see the new star so I’ve prepared a couple charts to help you find it. The first is a wide view to get situated; the second hones in to bring your directly to the galaxy. Be careful not to mix up M82 with its neighbor M81. M81 has a much rounder shape with a bright, distinct central core or nucleus. M82, an edge-on spiral galaxy, looks like a thin streak of light with a mottled texture. You’ll find the supernova west and south of M82’s center along the galaxy’s long axis. Look for a small star shining against the galaxy unresolved haze of stars.
Good luck in your quest to see one of the coolest sights in the night sky.