It seems like it wasn’t all that long ago that to see the planet Saturn, you had to get up just before dawn. Now it rises in the southeastern sky before midnight – 11:15 p.m. to be exact. Tonight it will come up with more than the usual fanfare. Watch around midnight and later when the waning gibbous moon and Spica join the planet in a compact celestial triangle.
Saturn’s still too low to get a clear view of its rings until after midnight when it rises above the atmospheric muck. A small telescope magnifying 30x or higher is all you need to see them and the planet’s brightest moon, Titan. Larger telescopes show more than one ring and additional moons. The monster ammonia ice storm/blizzard in Saturn’s cloud tops that began late last year has expanded to approximately the diameter of the planet or some 74,000 miles. That’s over 9 times the diameter of Earth! Look for it in the planet’s northern hemisphere, where it appears as a lighter-toned belt.
I was blown away Saturday night when I aimed my scope at a recently discovered supernova or exploding star in the galaxy NGC 2655 in the dim constellation Camelopardalis the Giraffe. Located not far from Polaris, this spiral galaxy is about 81 million light years from Earth.
Dozens of supernovae are discovered by amateur and professional astronomers each year in both near and remote galaxies. Although we might have to wait hundreds of years for one to show in the Milky Way, the odds of seeing them increase if we expand our sample to hundreds of thousands of galaxies. Numerous supernova search programs are underway, many of which are carried out by amateur astronomers. They select a set of galaxies, photograph them, and then compare the photos to reference photos taken earlier, looking for signs of “new” stars in the galaxies. Followup observations determine if the new star is really a supernova or just an asteroid passing by in the foreground.
The Japanese comet and supernova hunter Koichi Itagaki discovered the exploding star in NGC 2655 on January 7 when it was still very faint. Many supernovas remain faint and difficult to see in amateur telescopes, but this one was different. Within a week, it became bright enough to see in a 10-inch scope, and now it’s even visible in a 6-inch telescope.
A supernova looks like a star superimposed on a galaxy. 2011B must have been one heck of an explosion, because it’s currently brighter than the entire inner core of the galaxy. That’s what was so amazing Saturday night – seeing and realizing the power of a stellar blast bright enough to outshine the combined light of millions of stars. Wow!
Supernovas come in two basic varieties, Type II and Type Ia. When a supergiant star exhausts its supply of fuel, collapses and then rebounds, blowing itself to bits, that’s a Type II.
Type Ia originate in very close double stars, where one of the companions is a superdense star the size of Earth called a white dwarf. It orbits a normal star like the sun so closely, that the dwarf’s gravity pulls matter from its companion and funnels it down to its surface. When the white dwarf “gains more weight” than its core can support, the star collapses. This heats the core to billions of degrees in a matter of seconds, and the star goes up in a roar of nuclear flame. 2011B is a Type Ia and its brightness attests to a truly cataclysmic event in progress. Well, not in progress right now. It happened 81 million years ago and we’re just getting the news this month!
I realize some of you reading this may want to give the supernova a try. It won’t be easy if you’re a beginner, but if you know your way around the sky or have a computerized go-to telescope, you’re up to the challenge. To find the galaxy, you can use a printed star atlas or one of the many planetarium software programs such as the free Stellarium in my links column. Another option is the Virtual Telescope online atlas. Scroll up to the telescope part, type in the object’s position (R.A. = 8 55.6, Dec. = 78 13) and click on the Aim Telescope button. That will give you a general view. To get in closer, change the field of view to 10 or 12 degrees and the Deep Sky Object magnitude to 11.Â The supernova is a bit southeast of the galaxy’s center and currently magnitude 12.8, well within the range of a 6-inch scope under dark skies. Magnifications of 100x and up will show it as a star tucked into the galaxy’s hazy outer envelope.
Even if you’re unable to view the supernova, it’s fascinating to realize that an exploding star seeds space with many of the heavier elements needed for the formation of planets and life. You’re reading this because generations of stars burned out or blew up to get you here. For more pictures of 2011B and other supernovae, be sure to check out Joseph Brimacombe’s Flickr page. Another excellent resource on current supernovae is Dave Bishop’s Latest Supernovae site.