Universe Today
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the open star cluster known as Messier 37. Enjoy!
During the 18th century, famed French astronomer
Charles Messier
noted the presence of several "nebulous objects" in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list (known as the
Messier Catalog
) would come to include 100 of the most fabulous objects in the night sky.
One of these objects is the open star cluster known as Messier 37 (aka M37 and NGC 2099). Located in the direction of the
Auriga constellation
, Messier 37 is one of three open star clusters (including Messier 36 and Messier 38) in this portion of the night sky - and also the brightest.
Description:
Of the trio of Messier star clusters in this area, M37 is by far the most stellar populated. It contains at least 150 stars that are around magnitude 12 and easily resolved by even small telescopes - and science is still counting actual members! At around 347 - 550 million years old, you'll find at least a dozen red giants living here about 4,500 light years away from Earth... and they do it in a neighborhood that spans anywhere from 20 to 25 light years across!
[caption id="attachment_134322" align="aligncenter" width="580"]
The open star cluster Messier 37. Credit: Wikisky
[/caption]
Just how many stars might be inside this intermediate-aged cluster? As R. Sagar and Nilakshi of the Indian Institute for Astrophysics said in their
2002 study
:
Out of this huge number of stars, astronomers have been able to observe white dwarfs, too. This helps us to understand how they develop and what affects their helium or hydrogen content. Jasonjot Singh Kalirai et al. had the following to say in a
2004 study
:
So, we're setting the stage with number of stars and types. We have white dwarfs - but what about variables? Y.B. Kang (et al), put it this way in a
2007 study
:
[caption id="attachment_134323" align="aligncenter" width="580"]
M37 (NGC 2099) open cluster. Credit: Wikipedia Commons
[/caption]
So what does knowing about these two types of stars help with our understanding of stellar evolution? That's one of the goals of the RACE-OC project. As S. Messina (et al) said in
2008
:
History of Observation:
Although this great star cluster was originally recorded Giovanni Batista Hodierna before 1654, it would be 230 years before his records would be uncovered, so when Charles Messier first logged as Messier 37, it was believed to be an independent discovery.
While William Herschel would return in later years to study Messier's object, he did not publish his notes - but gives some great observing advice:
As always, Admiral Smyth was the most poetical about his observing, and of M37 he writes:
[caption id="attachment_134324" align="aligncenter" width="580"]
The location of Messier 37 in the constellation Auriga. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
[/caption]
Locating Messier 37:
Locating Messier 37 is relatively easy once you understand the constellation of Auriga. Looking roughly like a pentagon in shape, start by identifying the brightest of these stars - Capella. Due south of it is the second brightest star which shares its border with Beta Tauri, El Nath. By aiming binoculars at El Nath, go north about 1/3 the distance between the two and enjoy all the stars! You will note two very conspicuous clusters of stars in this area, and so did Le Gentil in 1749.
Binoculars will reveal the pair in the same field, as will telescopes using lowest power. The dimmest of these is the M38, and will appear vaguely cruciform in shape. At roughly 4200 light years away, larger aperture will be needed to resolve the 100 or so fainter members. About 2 1/2 degrees to the southeast (about a finger width) you will see the much brighter M36.
More easily resolved in binoculars and small scopes, this "jewel box" galactic cluster is quite young and about 100 light years closer. If you continue roughly on the same trajectory about another 4 degrees southeast you will find open cluster M37. This galactic cluster will appear almost nebula-like to binoculars and very small telescopes – but comes to perfect resolution with larger instruments.
While all three open star clusters make fine choices for moonlit or light polluted skies, remember that high sky light means less faint stars which can be resolved - robbing each cluster of some of its beauty. Messier 37 is the brightest and easternmost of the trio and you'll very much notice its density.
When you view this cluster with binoculars, you'll be seeing it much as Messier did... But use the power of a telescope if you can. Because this cloud of stars is quite worth your time and attention!
- Object Name
-
Messier 37
- Alternative Designations
-
M37, NGC 2099
- Object Type
-
Galactic Open Star Cluster
- Constellation
-
Auriga
- Right Ascension
-
05 : 52.4 (h:m)
- Declination
-
+32 : 33 (deg:m)
- Distance
-
4.4 (kly)
- Visual Brightness
-
6.2 (mag)
- Apparent Dimension
-
24.0 (arc min)
We have written many interesting articles about Messier Objects here at Universe Today. Here's Tammy Plotner's
Introduction to the Messier Objects
, ,
M1 – The Crab Nebula
,
M8 – The Lagoon Nebula
, and David Dickison's articles on the
2013
and
2014
Messier Marathons.
Be to sure to check out our complete
Messier Catalog
. And for more information, check out the
SEDS Messier Database
.
Sources: