NGC 2244
NGC 2244 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 O-type [main-sequence star|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.