Gum 23
Also called
RCW 38Coordinates: (268.03°, -0.98°)
[ Catalog | Explorer | SIMBAD ]
This giant star formation region at the boundary of the Vela OB1 association is a blister compact HII region lying just inside the edge of a giant molecular cloud. It is ionised by an enormous star cluster, [BDB2003] G267.92-01.06, that is less than 1 million years old and contains about 2000 stars (about 31 of these candidate O or B class stars). The hottest of these is the O5.5V class [FP74] RCW 38 IRS 2.
The RCW 38 cluster is less than 1 million years old and contains about 2000 stars (about 31 of these candidate O or B class stars). The hottest of these is the O5 class [FP74] RCW 38 IRS 2. RCW 38 itself appears to be a blister compact HII region lying just inside the edge of a giant molecular cloud.[1]
Includes an embedded cluster with 200 members detectable in X-rays.[2]
Avedisova adds three more ionising stars: the O4 III giant CPD -47 2963, the O9.5 Ia supergiant HD 78344 and the B0.5 II-Ib CD -47 4551. (SIMBAD gives a cooler O6 class for CPD -47 2963 and says that it is the same star as CD -47 4551.) She places RCW 38 in star formation region SFR 267.93-1.00 with 58 components, including 2 water masers, the supernova remnant CTB 31, at least half a dozen reflection nebulae, the HII region Gum 22, and the star cluster Muzzio 1.
A full colour infrared image was released by the ESO in 2010. A good black and white hydrogen-alpha image of this region can be found here, a Chandra X-ray image of the central cluster here and a MSX 8μm infrared image here.
The RCW catalog identifies four subnebulae, RCW 38a - 38d, as can be seen in this hydrogen-alpha image.
Gum describes this as a "Group of small fragments - possibly one object broken up by foreground obscuration." and places it within the boundary of the much larger nebula Gum 22.
Includes an embedded cluster with 200 members detectable in X-rays.[2]
Avedisova adds three more ionising stars: the O4 III giant CPD -47 2963, the O9.5 Ia supergiant HD 78344 and the B0.5 II-Ib CD -47 4551. (SIMBAD gives a cooler O6 class for CPD -47 2963 and says that it is the same star as CD -47 4551.) She places RCW 38 in star formation region SFR 267.93-1.00 with 58 components, including 2 water masers, the supernova remnant CTB 31, at least half a dozen reflection nebulae, the HII region Gum 22, and the star cluster Muzzio 1.
A full colour infrared image was released by the ESO in 2010. A good black and white hydrogen-alpha image of this region can be found here, a Chandra X-ray image of the central cluster here and a MSX 8μm infrared image here.
The RCW catalog identifies four subnebulae, RCW 38a - 38d, as can be seen in this hydrogen-alpha image.
Gum describes this as a "Group of small fragments - possibly one object broken up by foreground obscuration." and places it within the boundary of the much larger nebula Gum 22.
Notes
1. ^ Wolk, Scott J., Spitzbart, Bradley D., Bourke, Tyler L., et al. (2006). "X-Ray and Infrared Point Source Identification and Characteristics in the Embedded, Massive Star-Forming Region RCW 38", The Astronomical Journal, Vol. 132, 1100-1125. [2006AJ....132.1100W]
2. ^ Wolk, S., Spitzbart, B., Bourke, T., et al. (2003). "The Stellar Population of RCW 38", Bulletin of the American Astronomical Society, Vol. 35, 1219. [2003AAS...203.1005W]
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Most of the sources used to create these nebula descriptions are listed in the
notes section for each description. In some cases,
for example the Avedisova, Humphreys and Reed catalogs, the source is used extensively and is not listed in the
individual nebula descriptions. See this catalog overview
for more information on the catalogs and the general sources used
to create these descriptions and this introduction to HII regions
on the general history of this area of astronomy.
This image was created using the POSS-II/UKSTU data of the Digitized Sky Survey and SuperCOSMOS using the process described here.
According to my correspondence with the Royal Observatory Edinburgh and the Space Telescope Science Institute, I am allowed to use the POSS-II/UKSTU data to create and display images for non-commercial purposes so long as I include this fine print for the SuperCOSMOS data:
Use of these images is courtesy of the UK Schmidt Telescope (copyright in which is owned by the Particle Physics and Astronomy Research Council of the UK and the Anglo-Australian Telescope Board) and the Southern Sky Survey as created by the SuperCOSMOS measuring machine and are reproduced here with permission from the Royal Observatory Edinburgh.
and this acknowledgement taken from the DSS site:
The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.
The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation.
The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt.
The "Second Epoch Survey" of the southern sky was made by the Anglo-Australian Observatory (AAO) with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright ? 1993-5 by the Anglo-Australian Observatory Board, and are distributed herein by agreement.
The "Equatorial Red Atlas" of the southern sky was made with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright ? 1992-5, jointly by the UK SERC/PPARC (Particle Physics and Astronomy Research Council, formerly Science and Engineering Research Council) and the Anglo-Australian Telescope Board, and are distributed herein by agreement.
The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright ? 1993-1995 by the California Institute of Technology and are distributed herein by agreement. The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright ? 1993-1995 by the California Institute of Technology and are distributed herein by agreement.