Gum 7
Also called
Sh 2-307, RCW 12Coordinates: (234.56°, 0.83°)
[ Catalog | Explorer | SIMBAD ]
Avedisova lists the ionising stars as the O9 V BD -18 1920 and the B3 III giant LSS 566. Other sources also include the B0V star MFJ Sh 2-307 3. The nebula contains the infrared cluster candidate [DBS2003] 8.
A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud [JKK96] D within the enormous infrared ring called the GS234-02 supershell, in the Perseus arm.
You can view the enormous dust ring around the supershell in this WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.
Both Avedisova and a 2007 paper, however, give much closer distance estimates and thus appear to exclude this nebula from the supershell.
You can view a good Dean Salman image of this nebula here.
A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud [JKK96] D within the enormous infrared ring called the GS234-02 supershell, in the Perseus arm.
You can view the enormous dust ring around the supershell in this WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.
Both Avedisova and a 2007 paper, however, give much closer distance estimates and thus appear to exclude this nebula from the supershell.
You can view a good Dean Salman image of this nebula here.
The exciting star for this nebula is the B0V star MFJ Sh 2-307 3. It is part of the same giant molecular cloud complex that includes S299, S300, S305, S306 and S309 at 4200 pc.[1]
Contains infrared cluster candidate [DBS2003] 8. [2]
More on the GS234-02 supershell. [3]
Contains infrared cluster candidate [DBS2003] 8. [2]
More on the GS234-02 supershell. [3]
Notes
1. ^ Russeil, D., Georgelin, Y. M., Georgelin, Y. P., et al. (1995). "Galactic HII regions at l= 234deg.", Astronomy and Astrophysics Supplement Series, Vol. 114, 557. [1995A&AS..114..557R]
2. ^ 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]
3. ^ Jung, Jae Hoon, Koo, Bon-Chul, & Kang, Yong-Hee (1996). "GS234-02: A Star Forming Supershell in the Outer Galaxy", The Astronomical Journal, Vol. 112, 1625. [1996AJ....112.1625J]
Distance estimates
4200 pc [1995A&AS..114..557R]2650 pc +/- 400 [2007A&A...472..471M]
2370 pc +/- 100 [1984NInfo..56...59A]
Links
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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.