| NGC 2244 | |
|---|---|
 | |
| Observation data (J2000epoch) | |
| Right ascension | 6h 31m 54s[1] |
| Declination | +4° 56′[1] |
| Distance | 5.2kly |
| Apparent magnitude (V) | 4.8[1] |
| Apparent dimensions (V) | 24′ |
| Physical characteristics | |
| Radius | 18ly[2] |
| Other designations | Caldwell 50, Satellite Cluster,[3]NGC 2239,[4]Cr 99 |
| Associations | |
| Constellation | Monoceros |
| See also:Open cluster,List of open clusters | |
NGC 2244 (also known asCaldwell 50 or theSatellite Cluster) is anopen cluster in theRosette Nebula, which is located in theconstellationMonoceros. This cluster has severalO-type stars, super hot stars that generate large amounts ofradiation andstellar 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 is12 Monocerotis, a foreground K-classgiant. The two brightest members of the cluster are HD 46223 of spectral classO4V, 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 adouble star.[5] 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 thatbrown dwarfs in NGC 2244 form closer to OB-stars than to other stars.[6] This could be explained by thephotoevaporation of the outer layers ofprestellar cores that otherwise would form low-mass stars or intermediate mass stars.[7] The study also found a low disk fraction for low-mass objects of39%±9% for objects later thanK0.[6] One cluster member was discovered in the past to show signs of an eroding disk, reminiscent of aproplyd.[8]
Media related toNGC 2244 at Wikimedia Commons
