RCW 46
Coordinates: (282.4°, -1.3°)
[ Catalog | Explorer | SIMBAD ]
There are a wide range of distance estimates for this nebula.
Avedisova concludes that RCW 46 is ionised the O8 V class CP -56 2853 and 3 B-class stars at a distance of 1880 +/- 210 parsecs. She places it in star formation region SFR 282.32-1.33 along with the reflection nebula Bran 288. (According to a 1989 paper by Stark and Brand, Bran 288 has a distance of 1970 +/- 400 parsecs so this is consistent with the Avedisova information.)
Grabelsky associates RCW 45, RCW 47 and possibly RCW 46 with the 225 thousand solar mass molecular cloud [GCB88] 3 at a distance of 3200 parsecs.
According to a third source, RCW 45 and RCW 46 lie at the eastern edge of the chimney GSH 277+0+36. The chimney is at a distance of about 6500 pc on the outer edge of the Carina arc, is more than 600 pc in diameter, and extends at least 1000 pc above and below the Galactic midplane.
RCW 46 is located just below a huge cavity visible in infrared as can be seen in this MSX image, but little infrared emission is visible in the direction of RCW 46 itself. You can also see another infrared image of RCW 46 taken by 2MASS, which shows the infrared star group [DBS2003] 42 at its centre.
Avedisova concludes that RCW 46 is ionised the O8 V class CP -56 2853 and 3 B-class stars at a distance of 1880 +/- 210 parsecs. She places it in star formation region SFR 282.32-1.33 along with the reflection nebula Bran 288. (According to a 1989 paper by Stark and Brand, Bran 288 has a distance of 1970 +/- 400 parsecs so this is consistent with the Avedisova information.)
Grabelsky associates RCW 45, RCW 47 and possibly RCW 46 with the 225 thousand solar mass molecular cloud [GCB88] 3 at a distance of 3200 parsecs.
According to a third source, RCW 45 and RCW 46 lie at the eastern edge of the chimney GSH 277+0+36. The chimney is at a distance of about 6500 pc on the outer edge of the Carina arc, is more than 600 pc in diameter, and extends at least 1000 pc above and below the Galactic midplane.
RCW 46 is located just below a huge cavity visible in infrared as can be seen in this MSX image, but little infrared emission is visible in the direction of RCW 46 itself. You can also see another infrared image of RCW 46 taken by 2MASS, which shows the infrared star group [DBS2003] 42 at its centre.
Bran 288 has a distance of 1970 +/- 400 parsecs.[1]
RCW 45, RCW 47 and possibly RCW 46 are associated the 225 thousand solar mass molecular cloud [GCB88] 3 at a distance of 3200 parsecs.[2]
RCW 45 and RCW 46 lie at the eastern edge of the chimney GSH +277+0+036.[3]
Contains the infrared group [DBS2003] 42. [4]
A 2011 paper mistakenly identifies RCW 46 with the giant HII region G282.0-1.2. [5] However, G282.0-1.2 is visually obscured and RCW 46 is a distinct and smaller object located about a third of a degree away.
RCW 45, RCW 47 and possibly RCW 46 are associated the 225 thousand solar mass molecular cloud [GCB88] 3 at a distance of 3200 parsecs.[2]
RCW 45 and RCW 46 lie at the eastern edge of the chimney GSH +277+0+036.[3]
Contains the infrared group [DBS2003] 42. [4]
A 2011 paper mistakenly identifies RCW 46 with the giant HII region G282.0-1.2. [5] However, G282.0-1.2 is visually obscured and RCW 46 is a distinct and smaller object located about a third of a degree away.
Notes
1. ^ Stark, Antony A. & Brand, Jan (1989). "Kinematics of molecular clouds. II - New data on nearby giant molecular clouds", The Astrophysical Journal, Vol. 339, 763-771. [1989ApJ...339..763S]
2. ^ Grabelsky, D. A., Cohen, R. S., Bronfman, L., et al. (1988). "Molecular clouds in the Carina arm - The largest objects, associated regions of star formation, and the Carina arm in the Galaxy", The Astrophysical Journal, Vol. 331, 181-196. [1988ApJ...331..181G]
3. ^ McClure-Griffiths, N. M., Dickey, John M., Gaensler, B. M., et al. (2000). "Two Large H I Shells in the Outer Galaxy near L=279°", The Astronomical Journal, Vol. 119, 2828-2842. [2000AJ....119.2828M]
4. ^ Dutra, C. M., Bica, E., Soares, J., et al. (2003). "New infrared star clusters in the southern Milky Way with 2MASS", Astronomy and Astrophysics, Vol. 400, 533-539. [2003A&A...400..533D]
5. ^ Moisés, A. P., Damineli, A., Figuerêdo, E., et al. (2011). "Spectrophotometric distances to Galactic H II regions", Monthly Notices of the Royal Astronomical Society, Vol. 411, 705-760. [2011MNRAS.411..705M]
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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.