A Stellar Role : * The next few weeks will be ideal for viewing a nebula and star clusters--located close together in the early evening.
They go unnoticed by most of us: fuzzy patches of light dotting the night sky that appear too small to be of much importance in the universe.
But if you take a moment to peek through a pair of binoculars or a telescope, you can see that some of these objects not only dwarf our own solar system, they actually help scientists explain how our universe works.
The first few weeks of April will be the last time until winter that early-evening observers can glimpse these evolving stellar stages--called nebulae and star clusters--so close together.
Looking west soon after sunset, seek out the star Sirius, the brightest star in the sky, nicknamed the Dog Star. Don’t mistake it with the planet Venus, which is brighter and lower in the sky. Sirius lies in the collar of the constellation Canis Major, the Big Dog.
To the right of Sirius you will find three stars in a row. This is the belt of Orion the Hunter. Below the farthest left star in the belt is Orion’s sword--three faint objects descending at an angle toward the horizon.
The middle star in Orion’s sword is not a star at all, but the famous Orion Nebula, about 1,600 years away from us if we were traveling at the speed of light (called light-years). A massive swarm of interstellar hydrogen gas and dust that could swallow 20,000 of our solar systems, the Orion Nebula is an interstellar womb for stars.
Visible as a gray filament, the Orion Nebula is collapsing through gravity to create stars powered by the fusion of hydrogen atoms into helium. An average star like our sun takes about 50 million years to form. The Orion Nebula contains enough matter to create hundreds of thousands of stars.
Using the three belt stars of Orion to point to the right, we pass the star Aldebaran, the eye of Taurus the bull, and encounter a smattering of faint stars called the Pleiades. This open cluster of stars lies about 400 light-years away.
If the Orion Nebula is a stellar womb, the Pleiades could be viewed as stars in preschool. Relatively young (not more than 100 million years old), open clusters have been nudged from their nebulae birthplace by the rotation of our Milky Way galaxy. This movement will cause the cluster to eventually dissolve.
Although only seven stars are visible to the naked eye in the Pleiades, there are actually a few hundred in the cluster, a few dozen of which are visible with binoculars.
On the opposite side of Orion lies another open cluster, called the Beehive, in the constellation of Cancer the Crab. At 500 light-years away, the Beehive is a challenge to spot with the naked eye. Binoculars bring many of the cluster’s estimated 200 stars into focus.
With a telescope, you can see brilliant blue-white stars, which photographs reveal to be accompanied by a faint blue nebula remnant, left from the formation of the stars.
At the tip of the right horn of Taurus the Bull lies the Crab Nebula, about 6,300 light-years away. Visible as a faint gray cloud in an eight-inch diameter telescope, this is the remnant of an exploding star that was so powerful it could be seen in daylight from Earth, in the year 1054 A.D.
It is this expelled star stuff, as well as matter shed occasionally from dying, red supergiant stars like Betelgeuse (the armpit of Orion), that is the seed for a new generation of stars.
So if anybody asks how the universe works, just point to the sky and tell them it’s recycling itself.
WHERE AND WHEN
What: Los Angeles Valley College Astronomy Club’s monthly planetarium shows and (weather permitting) observing through its 16-inch telescope.
Location: Valley College Planetarium and Observatory, 5800 Fulton Ave., Van Nuys.
When: The next star party is April 9, featuring a 5:30 p.m. trek to the Mt. Wilson area. Next planetarium / observing session at the college will be at 8 p.m. April 15.
Price: Mt. Wilson trip is free. Planetarium shows are $3.50 general, $2.50 seniors and $2 for kids 8 to 16. No kids younger than 8 allowed.
Call: (818) 781-1200, Ext. 335.
