Minnesota Starwatch

University of Minnesota

Department of Astronomy

Minnesota Starwatch for March 2004
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Starwatch Newsletter

Minnesota Starwatch is a newsletter describing the night sky in the Midwest.

It is updated monthly, and is produced by the
Department of Astronomy, University of Minnesota
116 Church Street SE, Minneapolis, MN 55455

Minnesota Starwatch for March 2004

Hello, this is Minnesota Starwatch for March 2004. The western sky early in the evening is still dominated by the spectacular, rich constellations of winter. Most prominent among these is the hourglass-shaped constellation of Orion, the Great Hunter. As he has for aeons, Orion pursues his prey Taurus, the Bull, who is fleeing westward. Three bright stars across the center of the hourglass define Orion's belt. At the tip of the sword that hangs from the belt is Messier 42, one of the most active star formation regions in our Galaxy. M42, popularly called the Orion Nebula, is spectacular when viewed through small telescope or binoculars. You should be able to pick out the four hot young stars of the Trapezium, surrounded by a large greenish gaseous nebula. Three more hot young stars can be seen just to the southeast of the Trapezium. The new NASA Spitzer Space Telescope (http://www.spitzer.caltech.edu/). , an infrared observatory that was launched on August 25, 2003, is now returning stunning images of stellar nurseries that are similar to M42. Some recently acquired examples are the Spitzer images of newborn stars in the rosebud-shaped, rose-colored nebula NGC 7129, 3300 light-years away in the autumn constellation Cepheus, now behind the sun (http://www.spitzer.caltech.edu/Media/releases/ssc2004-02/ssc2004-02a.shtml) and the protostars in the dark globule IC 1396 (http://www.spitzer.caltech.edu/Media/releases/ssc2003-06/ssc2003-06b.shtml).

Betelgeuse, the reddish star that defines the northeast corner of the Orion hourglass, is a swelled-up star called a red supergiant. This is a phase that massive stars enter when they exhaust the hydrogen fuel that sustains their heat during most of their lifetime. When Betelgeuse reaches the end of its supergiant phase, sometime within the next few million years, earthlings will be treated to a spectacular sight as it erupts in a supernova explosion. The explosion, caused by the rapid gravitational collapse of the fuel-exhausted core, will cause Betelgeuse to become 10 billion times as luminous as the sun, and even at earth it will approach the full moon in brightness! Within a year, the ejected shell will be big enough to be seen easily with a small telescope, and the explosion will be seen reflected off the nearby Orion dust clouds for many years. Of course, since Betelgeuse is 540 light-years away, the explosion will not be seen on earth until the year 2544 even if it were to happen tomorrow!

The five bright classical planets can be viewed simultaneously at dusk in late March. Venus, the "Evening Star," will be brilliant and high in the west as Jupiter, second only to Venus in radiance, climbs rapidly during the evening in the east. Jupiter will actually be exactly opposite the earth from the sun on March 3rd. This condition is called "opposition". Venus will rise to its greatest elevation in eight years, and will set a full four hours after the sun on March 29th. Mars, the "red planet", will pass within a few degrees of the Pleiades on March 20th. The Pleiades (The Seven Sisters), a young star cluster with seven bright members, will be setting in the Northwest. This young open star cluster is another excellent viewing target for binoculars or a small telescope. Mercury will climb into view after mid-March. Saturn, whose rings are still tilted at nearly their maximum opening angle, will be high in the west at sunset.

Friday night telescope viewing at the U's Astronomy Department begins at 8pm. Please call (612) 626- 0034 for more information. For fun Astronomy Outreach programs check out our Public Outreach link, or if you're interested in how you can help build the new Minnesota Planetarium, please call 612-630-6151 or visit http://www.mplanetarium.org. Como Planetarium is offering fun family shows about astronomy on a limited basis; please call 651-293- 5398 for more info! This has been a Minnesota Starwatch produced by the University of Minnesota Astronomy Department.