We may usually think of a supernova as a gloriously brilliant exploding star, one of these exceedingly rare events that are witnessed by the masses every few hundred years. Indeed, on the infrequent times in history a supernova has burst on the starry dome of night, it has inspired wonder, fear and stuff of legends.
We may usually think of a supernova as a gloriously brilliant exploding star, one of these exceedingly rare events that are witnessed by the masses every few hundred years.
Indeed, on the infrequent times in history a supernova has burst on the starry dome of night, it has inspired wonder, fear and stuff of legends.
A supernova now visible in the evening sky, however, needs at least a small telescope. It has excited the astronomical community as it is one of the brightest supernova seen in 20 years, although it is VERY far away. In fact it is about 250 million light years from Earth, in the neighboring galaxy known as M101. The supernova has been designated SN 2011fe.
It was first imaged on Aug. 24 and has been brightening ever since.
With a good star chart and small telescope, you can find M101 on a dark night just off the handle of the Big Dipper.
Normally, you would never be able to discern any of the stars that make up this or any other galaxy beyond our Milky Way in your eyepiece. The galaxies are so far from us that their individual stars are hopelessly dim. Some stars in other galaxies have been recorded photographically.
M101 is a huge spiral galaxy - about 10 times the mass of our own Milky Way, with trillions of stars.
What makes this so interesting is that one of those remote stars that make up M101 has risen from obscurity, exploding in magnitude so bright you can see it even with a 2-inch telescope or large binoculars, piercing even the moonlight. It’s all a matter of perspective. Currently glowing at about +10th magnitude, the supernova masquerades as any of millions of 10th magnitude stars in the Milky Way that you can see in your backyard telescope. Yet this star is in another galaxy, far, far away!
It would be an amazing beacon of light from a planet within M101.
Termed a “Type 1a” supernova, the explosion occurs in a close double star system where stellar material being drawn from one star onto a dense white dwarf star reached a certain critical mass 1.4 times the mass of our sun. They are important to astronomers for calibrating distances to galaxies. All Type 1a supernovae are believed to reach a similar level of brightness, so their apparent magnitude as seen from Earth is a way of judging the distance.
Note that the unaided eye can see stars as faint at +6th magnitude or in some cases +7th, at very dark locations. The higher the magnitude number, the dimmer is the star. You can find more information on the supernova at Sky and Telescope Magazine’s website, www.skyandtelscope.com, and other sources. For detailed information, see www.aavso.org.
Small telescopes capable of seeing +10th magnitude stars and a whole lot more from the wealth of craters on the moon to the ring system of Saturn, are available at around $100 to $150. Star maps and practical observing guides are readily available at many libraries and online. With a little experience and patience, your horizons will be literally expanded to the galaxies and your interest can explode like a supernova.
Meanwhile, we wait for the next supernova to appear in our own Milky Way Galaxy and dazzle our unaided eyes. Most are hidden by vast cosmic clouds of dust, but we never know when one may be ready to shine.
Last-quarter moon is on Sept. 27. Send your notes to email@example.com.
Keep looking up!