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Looking Up column: Auriga the Chariot Driver riding high

Peter Becker
More Content Now USA TODAY NETWORK
Star cluster M37 is the richest and brightest of several in the constellation Auriga.

Look straight up the next clear night, around 9 p.m. If you live in mid-northerly latitudes you will be gazing upon the beautiful, bright yellow star Capella and its interesting constellation, Auriga the Chariot Driver.

We can think of it as a star pattern for the fellows who make a living running a chariot. Next, it will be taxi and bus drivers.

This extremely ancient constellation, according to Greek legend, represents Erichthnoius, fourth King of Athens, the son of Vulcan and Minerva. He had trouble walking, so he invented a four-horse chariot.

Traditionally, Auriga is illustrated as a chariot with the driver who is holding a goat and her kids. Three of the dimmer stars in the constellation’s outline are nicknamed as the “kids.”

Capella is the third brightest star visible (magnitude 0.08) in the Northern Hemisphere and is so close to the pole that north of 44 degrees latitude, Capella is circumpolar, never setting below the horizon. Where I live in northeastern Pennsylvania (just shy of 42 degrees), Capella briefly goes below the flat northerly horizon every day.

Capella is actually a group of four stars, in the same system, and is about 43 light-years away.

Just south of Capella are the “kids.” One of these stars, Epsilon Aurigae, is an unusual eclipsing binary star. About every 27 years, the star dips in brightness almost a whole magnitude, from +2.92 to +3.83, and stays at its dimmest for 640 to 730 days.

Its last fainting episode ended in 2011.

Theories have raged in astronomical circles over this star’s behavior. Since 2008, the most popular model says that the brighter star of this system is orbited by a companion that is shrouded in a massive, opaque disc of dust.

The moon reaches full stage this week on Thursday, Jan. 28, so the dimmer stars of Auriga will be quite hard to see with unaided eyes.

After Jan. 28, the moon will be rising later and later, giving us an increasingly long evening window of relative darkness, letting more starlight be seen.

Once the sky is dark enough, be sure to scan the stars of Auriga with a pair of binoculars.

The Milky Way band passes through Auriga and is faintly visible on clear, moonless nights away from city lights. The Milky Way band, made up of neighboring, overlapping arms of our great Milky Way spiral galaxy, presents a multitude of stars and open star clusters.

A telescope will show even more, but binoculars are plenty to show you the three brightest star clusters in Auriga. French astronomer Charles Messier (1730-1817), who was making a catalog of deep-sky objects that he could rule as being comets, listed these clusters as M37, M36 and M38 - in that order.

No two star clusters are alike, in richness, configuration or in how easy they are to see. The Pleiades is surely the most well known open star cluster, being bright and compact. The Pleiades is to the lower right (southwest) of Auriga.

M37, M36 and M38 are all rich in stars, but M37 leads the other two and is the brightest.

M37 shines at magnitude +6.2, visible as a fuzzy “star” to unaided eyes on a very dark, rural night.

The Pleiades is so prominent to our eyes because the cluster is relatively nearby, 444 light-years away.

M37 is listed as 4,200 light-years away and M36 and M38, both around 3,900 light-years from the sun. Imagine our sky if these clusters were as close as the Pleiades!

The Auriga clusters will appear as fuzzy patches in binoculars, partly resolved into stars, depending on your binoculars and sky conditions. A small telescope is needed to show them in their glory.

Auriga’s outline is shaped like an uneven pentagon, depending on how you connect the dots (I mean, stars). If you think of Capella as the chariot driver’s eye, the “kid” stars nearby can be imagined as the nose. A dimmer star can also be connected to form a cap for our driver.

The star pattern is also interesting because one of the corner stars is not in Auriga at all. The star on the opposite end of the pattern from Capella is Beta Tauri, a star in the adjacent pattern, Taurus the Bull.

Auriga and Taurus both ride higher in the sky than winter’s most famous constellation, Orion.

Keep looking up at the sky!

Peter Becker is managing editor at The News Eagle in Hawley, Pennsylvania. Notes are welcome at news@neagle.com. Please mention in what newspaper or website you read this column.

Auriga the Chariot Driver. The three little dots at the left marks the star cluster M37. M38 is in the center. M36, not marked, is about halfway between and a little lower. The star nearest to Capella (lower right) is Epsilon Auriga. The driver's foot at the left is marking the star Beta Tauri.