NGC 2244

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title: "NGC 2244" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["open-clusters", "monoceros", "ngc-objects", "caldwell-objects"] description: "Open cluster within the Rosette nebula, in the constellation Monoceros" topic_path: "general/open-clusters" source: "https://en.wikipedia.org/wiki/NGC_2244" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Open cluster within the Rosette nebula, in the constellation Monoceros ::

::data[format=table title="Infobox open cluster"]

Field	Value
image	File:Rosette Nebula in Monoceros.jpg
name	NGC 2244
epoch	J2000
ra	{{cite simbad
title	NGC 2244
access-date	2007-04-20}}
dec
dist_ly	5.2 kly
appmag_v	4.8
size_v	24
radius_ly	18 ly
constellation	Monoceros
names	Caldwell 50, Satellite Cluster, NGC 2239, Cr 99
::

| image = File:Rosette Nebula in Monoceros.jpg |caption= | name = NGC 2244 | epoch = J2000 | ra = {{cite simbad | title=NGC 2244 | access-date=2007-04-20}} | dec = | dist_ly = 5.2 kly | dist_pc = | appmag_v = 4.8 | size_v = 24 | radius_ly = 18 ly | absmag_v = | constellation = Monoceros | notes = | names = Caldwell 50, Satellite Cluster, NGC 2239, Cr 99 ::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c1/Ngc2244c.jpg" caption="An [[infrared]] [[Spitzer Space Telescope]] (SIRT) image of NGC 2244.
Credit: SIRT/[[NASA"] ::

NGC 2244 (also known as Caldwell 50 or the Satellite Cluster) is an open cluster in the Rosette Nebula, which is located in the constellation Monoceros. This cluster has several O-type stars, super hot stars that generate large amounts of radiation and stellar wind.

The age of this cluster has been estimated to be less than 5 million years. The brightest star in the direction of the cluster is 12 Monocerotis, a foreground K-class giant. The two brightest members of the cluster are HD 46223 of spectral class O4V, 400,000 times brighter than the Sun, and approximately 50 times more massive, and HD 46150, whose spectral type is O5V, has a luminosity 450,000 time larger than that of our star, and is up to 60 times more massive, but it may actually be a double star. These stars do not seem to pulsate, which is in agreement with stellar modeling of stars with similar global parameters.

A study from 2023 found that brown dwarfs in NGC 2244 form closer to OB-stars than to other stars. This could be explained by the photoevaporation of the outer layers of prestellar cores that otherwise would form low-mass stars or intermediate mass stars. The study also found a low disk fraction for low-mass objects of for objects later than K0. One cluster member was discovered in the past to show signs of an eroding disk, reminiscent of a proplyd.

References

References

1. distance × sin( angular diameter / 2 )
2. "The Rosette Nebula In Hubble Palette.".
3. "Notes on the NGC objects, particularly those missing, misidentified, or otherwise unusual (ngcnotes.all).".
4. A quantitative study of O stars in NGC 2244 and the Monoceros OB2 association, Martins, F.; Mahy, L.; Hillier, D. J.; Rauw, G., ''Astronomy and Astrophysics'' '''538''', pp. A39, {{bibcode. 2012A&A...538A..39M, {{doi. 10.1051/0004-6361/201117458.
5. (2023-05-01). "Spectroscopic substellar initial mass function of NGC 2244". Astronomy and Astrophysics.
6. (2004-11-01). "The formation of free-floating brown dwarves and planetary-mass objects by photo-erosion of prestellar cores". Astronomy and Astrophysics.
7. (2006-10-01). "Spitzer MIPS 24 μm Detection of Photoevaporating Protoplanetary Disks". The Astrophysical Journal.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::