The bright starAlnitak (ζ Ori), the easternmost star in theBelt of Orion, appears very close to the Flame Nebula in the sky. But the star and nebula are not physically associated with one another. The Flame Nebula contains a young cluster of stars which includes at least one hot, luminous O-type star labeled IRS 2b.[2] The dense gas and dust in the foreground of the nebula heavily obscures the star cluster inside the nebula, making studies at infrared wavelengths most useful.
The energeticultraviolet light emitted by the central O-type star IRS 2b into the Flame Nebula causes the gas to be excited and heated. The glow of the nebula results from the energy input from this central star. Within the nebula and surrounding the central hot star is acluster of young, lower-mass stars,[3] 86% of which havecircumstellar disks.[4]X-ray observations by theChandra X-ray Observatory[5][6] show several hundred young stars, out of an estimated population of 800 stars.[7] X-ray and infrared images indicate that the young stars are concentrated near the center of the cluster.[8][9]
The center of the Flame Nebula seen by JWSTNIRCam, revealing proplyds in new detail and revealing two new candidates.
The Flame Nebula was observed withALMA and this study found two populations, which are separated by a molecular cloud. The eastern population is 0.2-0.5 Myr old and has a disk fraction of 45±7%. The western population is slightly older at 1 Myr and has a lower disk fraction of 15±4%.[10] This disk fraction is lower than the one observed in the mid-infrared,[4] but the ALMA survey also observed a smaller region.[10] The eastern part contains the O8 star IRS 2b and the western part contains the B0.5V star IRS 1. Hubble observations have shown that the Flame Nebula contains 4 clearproplyds and 4 candidate proplyds. Three of these are in the older western region and are pointing towards IRS 1. The other 5 are in the younger eastern region and are pointing towards IRS 2b.[11]
^abMeyer, M. R.; et al. (2008). "Star Formation in NGC 2023, NGC 2024, and Southern L1630". In Reipurth, B. (ed.).Handbook of Star Forming Regions, Volume II: The Southern Sky ASP Monograph Publications. Vol. 5. Astronomical Society of the Pacific. p. 43.Bibcode:2008hsf1.book..662M.ISBN978-1-58381-670-7.
