“Once you have tasted flight, you will forever walk the Earth with your eyes turned skyward, for there you have been, and there you will always long to return.” –Leonardo da Vinci
Welcome back to another exciting Messier Monday here on Starts With A Bang! As Comet ISON dives towards the Sun and a nearly perfect full Moon towers overhead, it’s easy to forget about those wondrous deep-sky objects that are fixed, but the 110 prominent members of the Messier Catalogue are always on tap for dedicated skywatchers. Although the extended objects — galaxies and nebulae — are difficult to view with a bright Moon out, the star clusters, both open clusters and globulars, still make for spectacular viewing.
Today, we’re going to highlight one of the dimmer (and thus, often overlooked) open star clusters of the Messier Catalogue, still clearly visible with even a small telescope or binoculars, provided you know where to look: Messier 36. For those of you who are night owls with clear skies, you may have noticed the recent appearance of the famed winter constellation Orion; that will be your guide to finding this week’s Messier object.
The Moon is famous among skywatchers for not only being a towering, brilliant source of light, but also for being a terrible source of light pollution. Tonight’s practically full Moon means that the night sky’s immediate vicinity around it at a total wilderness site is about as polluted as the night sky in a downtown urban area of a large (Seattle-sized) city. But that doesn’t mean you can’t still see the absolute brightest stars; Orion rises at around 9 PM over the Eastern horizon and even farther above it is the constellation of Auriga, heralded by brilliant Capella, the third brightest star in the entire Northern Hemisphere, behind only Arcturus and Vega.
Auriga makes an oval-like shape, with bright blue Alnath on the narrow end, opposite Capella and Menkalinan. (Alnath is technically in the constellation of Taurus, but it’s by less than a single degree; I’m far from the only one who always thinks of it as part of Auriga.) If you draw an imaginary line from Alnath back towards Menkalinan, you’ll come to the naked eye star χ Aurigae, which should still be visible even with the full Moon nearby.
And if you navigate from Alnath to χ Aurigae and head just a little bit farther in that same direction, you won’t be able to miss a very nice cluster of stars — Messier 36 — in either a telescope or binoculars.
This open star cluster is often challenging if you don’t know where to look, as it takes up a very small region on the sky (just a fifth of a degree) and is invisible to the naked eye under ideal dark-sky conditions. Nevertheless, it had been known for more than century before Messier catalogued it, noting it as a:
Cluster of stars in Auriga, near the star Phi: with an ordinary telescope… one has pain to distinguish the stars, the cluster contains no nebulosity.
And if you viewed it in an instrument of Messier’s power, you might well reach the same conclusion.
It seems like it barely stands out at all against the backdrop of other stars of similar magnitude. But what appears to be a small and unspectacular collection of dim stars from our point of view is actually an incredible sight, if we’re willing to take a look inside.
A glittering array of mostly blue stars that’s quite concentrated, Messier 36 has two particularly bright stars located at its center. Although they might not have stood out to Messier, even a 3″ (80 mm) telescope is good enough to see that brilliant central pair!
And if you’re willing to dive in with a really high-quality telescope, you can find out a whole lot more!
A quite young cluster with no red giant stars inside, the bluest star found in Messier 36 is of spectral class B2, just barely below the threshold of stars that end their lives in supernovae!
The reason this cluster appears so small and faint is because it’s so far away; at a distance of 4,100 light years it’s one of the top-10 most distant Messier open clusters, some ten times as far away as the Pleiades. At its current distance, it’s 14 light years in diameter, making it almost the same physical size as the Pleiades, and based on the stars we find in there, it’s only 25 million years old; our Sun is nearly 200 times older!
At least 60 individual stars have been identified in this cluster, although it’s easily conceivable that there are hundreds — if not as many as a thousand — in there that are simply hidden from our view thus far. It’s no wonder; like most open star clusters, Messier 36 is indeed located right in the galactic plane!
Still, you might ask yourself whether there was anything interesting to learn in the infrared. Is there dust? Red stars simply invisible to our visible eyes? Something else?
It looks like — if you didn’t know better — a shooting, red star is in there, doesn’t it?
What’s amazing is that, to the best we’ve been able to tell, there really is something interesting in there!
What is that thing? If only there were a better image to find out! In the meantime, this is the best I’ve been able to find!
It looks like a star whipping through the interstellar medium so quickly it’s grown a tail, similar to the well-known star Mira, but until better data comes along, it will have to remain a mystery! With that said, it’s a great sight for now and all through the entire winter, even when the Moon is at its brightest! And that will have to wrap up another Messier Monday! Including today’s entry, we’ve explored at the following Messier objects:
- M1, The Crab Nebula: October 22, 2012
- M2, Messier’s First Globular Cluster: June 17, 2013
- M5, A Hyper-Smooth Globular Cluster: May 20, 2013
- M7, The Most Southerly Messier Object: July 8, 2013
- M8, The Lagoon Nebula: November 5, 2012
- M11, The Wild Duck Cluster: September 9, 2013
- M12, The Top-Heavy Gumball Globular: August 26, 2013
- M13, The Great Globular Cluster in Hercules: December 31, 2012
- M15, An Ancient Globular Cluster: November 12, 2012
- M18, A Well-Hidden, Young Star Cluster: August 5, 2013
- M20, The Youngest Star-Forming Region, The Trifid Nebula: May 6, 2013
- M21, A Baby Open Cluster in the Galactic Plane: June 24, 2013
- M25, A Dusty Open Cluster for Everyone: April 8, 2013
- M29, A Young Open Cluster in the Summer Triangle: June 3, 2013
- M30, A Straggling Globular Cluster: November 26, 2012
- M31, Andromeda, the Object that Opened Up the Universe: September 2, 2013
- M32, The Smallest Messier Galaxy: November 4, 2013
- M33, The Triangulum Galaxy: February 25, 2013
- M34, A Bright, Close Delight of the Winter Skies: October 14, 2013
- M36, A High-Flying Cluster in the Winter Skies: November 18, 2013
- M37, A Rich Open Star Cluster: December 3, 2012
- M38, A Real-Life Pi-in-the-Sky Cluster: April 29, 2013
- M39, The Closest Messier Original: November 11, 2013
- M40, Messier’s Greatest Mistake: April 1, 2013
- M41, The Dog Star’s Secret Neighbor: January 7, 2013
- M44, The Beehive Cluster / Praesepe: December 24, 2012
- M45, The Pleiades: October 29, 2012
- M48, A Lost-and-Found Star Cluster: February 11, 2013
- M51, The Whirlpool Galaxy: April 15th, 2013
- M52, A Star Cluster on the Bubble: March 4, 2013
- M53, The Most Northern Galactic Globular: February 18, 2013
- M56, The Methuselah of Messier Objects: August 12, 2013
- M57, The Ring Nebula: July 1, 2013
- M60, The Gateway Galaxy to Virgo: February 4, 2013
- M65, The First Messier Supernova of 2013: March 25, 2013
- M67, Messier’s Oldest Open Cluster: January 14, 2013
- M71, A Very Unusual Globular Cluster: July 15, 2013
- M72, A Diffuse, Distant Globular at the End-of-the-Marathon: March 18, 2013
- M73, A Four-Star Controversy Resolved: October 21, 2013
- M74, The Phantom Galaxy at the Beginning-of-the-Marathon: March 11, 2013
- M75, The Most Concentrated Messier Globular: September 23, 2013
- M77, A Secretly Active Spiral Galaxy: October 7, 2013
- M78, A Reflection Nebula: December 10, 2012
- M81, Bode’s Galaxy: November 19, 2012
- M82, The Cigar Galaxy: May 13, 2013
- M83, The Southern Pinwheel Galaxy, January 21, 2013
- M86, The Most Blueshifted Messier Object, June 10, 2013
- M92, The Second Greatest Globular in Hercules, April 22, 2013
- M94, A double-ringed mystery galaxy, August 19, 2013
- M97, The Owl Nebula, January 28, 2013
- M99, The Great Pinwheel of Virgo, July 29, 2013
- M101, The Pinwheel Galaxy, October 28, 2013
- M102, A Great Galactic Controversy: December 17, 2012
- M103, The Last ‘Original’ Object: September 16, 2013
- M104, The Sombrero Galaxy: May 27, 2013
- M108, A Galactic Sliver in the Big Dipper: July 22, 2013
- M109, The Farthest Messier Spiral: September 30, 2013
Come back next week, where another deep-sky object — and another unique story about the Universe — awaits you here, only on Messier Monday!