Well, it finally happened. Supernova 2011fe in the Pinwheel Galaxy broke the 12th magnitude barrier overnight and now joins a select group of about 14 other supernovae that peaked at that brightness or better. And the fun’s not over yet.
Last night I saw it easily at magnitude 11.7 in a larger telescope, but it was even faintly visible in my wee 4.5 inch reflecting telescope, one of the most common small scopes you can buy.
While the star will undoubtedly be brighter yet tonight, perhaps even cracking the Top Ten, it probably won’t soar to the heights of the supernova that appeared in the Andromeda Galaxy in 1885*. That one shot all the way up to 5.8 and became briefly visible with the naked eye under dark skies. It was the first supernova seen in a galaxy beyond our own Milky Way. The more recent supernova 1987A in the Large Magellanic Cloud, a nearby satellite galaxy of the Milky Way, topped out even brighter at magnitude 2.8 in 1987 and was plainly visible without optical aid. And finally, we have to go back to 2004 and the galaxy NGC 2403 for the last supernova outside the Milky Way system that was as brighter than 2011fe is at present. Certainly that makes this event very special.
While there are physical differences in the supernovae that make one shine brighter or fainter than the other, the main reason why some are bright and some are not has more to do with distance. Other factors being equal, the closer to our own Milky Way a galaxy is, the brighter a supernova will appear. It’s the same with light bulbs — a bulb only two feet from your face looks a lot brighter than one a quarter mile away.
I encourage you to go out for a look if you have a telescope. As you’ve read, it’s not often we have such a stellar show. Here are links to two maps to help you find it. As of last night, SN 2011fe was the brightest star seen in the main body of the galaxy, outshining all the Milky Way foreground stars. When you look at the galaxy in your telescope and all you see is blurry spot and a single star shining within, that’s it!
Closer to Mother Earth, NASA recently released new photos from the Cassini Mission at Saturn of the odd little moon Hyperion. They were snapped during the August 25 flyby. The 168-mile wide Hyperion is composed mostly of ice and riddled with so many craters, it has the appearance of a giant sponge. Indeed, the moon’s density is so low, its interior may well be wormy with caverns.
Hyperion is peculiar in another way. It’s the only moon in the solar system known to rotate chaotically. Its axis of rotation wobbles this way and that so much, it was hard to know in advance exactly what part of the moon the Cassini craft would be photographing. Scientists believe its irregular shape, very elliptical (cigar-shaped) orbit and interactions with Saturn’s largest moon, Titan, may be behind its chaotic ways. Click HERE for more photos of Hyperion.
* References: Supernovae and how to observe them by Martin Mobberly, 2007
and David Bishop’s Latest Supernovae site