RCW 38
Emission nebula and star cluster
From Wikipedia, the free encyclopedia
RCW 38 is a star-forming region in the southern constellation of Vela (known as the Sails).[2] It includes an embedded HII region and a super star cluster. This region is located at a distance of approximately 5,500 light-years from the Sun.[1]
| RCW 38 | |
|---|---|
Nebulosity around the embedded star cluster in RCW 38 | |
| Observation data (J2000 epoch) | |
| Right ascension | 08h 59m 05.52s[1] |
| Declination | −47° 30′ 39.2″[1] |
| Distance | 5,500 ly (1.7 kpc)[1] |
| Physical characteristics | |
| Associations | |
| Constellation | Vela |
This is the youngest super star cluster in the Milky Way galaxy, with age estimates ranging from 0.1 to 1.0 Myr. It has around 10,000 member stars.[3] The cluster member stars are still enshrouded within the dark cloud in which they were born.[4] The star cluster is surrounded by clouds of brightly glowing gas and includes many protostars.[4] Observations by the Chandra X-ray Observatory have revealed more than 800 X-ray emitting young stellar objects in the cluster.[5] 139 infrared sources have been identified as variable, of which 47% are candidate young stellar objects.[6] Jets emerging from young protostars drive further star formation in the surrounding cloud.[7]
The cluster includes about 20 massive O-type stars concentrated in a volume a few parsecs across. The latter stars are having a dissipative effect on the surrounding molecular gas.[3] Five bow shocks have been identified coming from these objects, driven by strong stellar winds.[7] When these massive stars die, likely before the dispersal of the cluster, they will explode as supernovae.[2] It is hypothesized that these O-type stars were formed by a collision of two molecular clouds.[8] The primary cloud has a mass of 3×104 M☉, while the secondary cloud has 2×103 M☉.[3]
In the infrared, the brightest star in this region is designated IRS 2.[9] This is a binary star system consisting of two spectral type O5.5 stars. It is located at the heart of the cluster,[10] and appears to lie at the center of the H II region.[11] The second brightest source is a dust ridge designated IRS 1, positioned about 0.1 pc to the west of IRS 2. Both sources are surrounded by a dust-free cavity about 0.1 pc across.[3]
RCW 38 includes Gum 22, Gum 23, and Gum 24.[12][clarification needed]
Gallery
The location of RCW 38 (circled in red)
An X-ray view of the dense central star cluster
Central part of RCW 38, showing some of the brown dwarf candidates detected within the cluster[13]
The wider region surrounding RCW 38
