NGC 6357

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NGC 6357
emission nebula
H II region
EmissionNebula NGC6357.jpg
A Hubble Space Telescope (HST) image of Pismis 24-1, the "core" of NGC 6357
Credit: HST/NASA/ESA
Observation data: J2000 epoch
Right ascension 17h 24m[1]
Declination −34° 20′[1]
Distance ~ 8000[2] ly
Constellation Scorpius[3]
Designations War and Peace Nebula,[1] Lobster Nebula [4] Sharpless 11, RCW 131, Gum 66
See also: Lists of nebulae

NGC 6357 is a diffuse nebula near NGC 6334 in the constellation Scorpius. The nebula contains many proto-stars shielded by dark disks of gas, and young stars wrapped in expanding "cocoons" or expanding gases surrounding these small stars. It is also known as the Lobster Nebula[4][5]

This nebula was also given the name War and Peace Nebula by the Midcourse Space Experiment scientists because of its appearance. They said that in infrared images the bright, western part resembles a dove, while the eastern part looks like a skull.[6]

Pismis 24[edit]

This nebula includes the open cluster Pismis 24, which is home to several massive stars. One of the brightest stars in the cluster, Pismis 24-1, was thought possibly to be the most massive on record, approaching 300 solar masses, until it was discovered to be a multiple system of at least three stars; component stars would still remain near 100 solar masses, making them among the more massive stars on record.[7][8]

Prominent stars in Pismis 24[9]
Star
(Pismis 24-#)
Spectral type Magnitude
(Mbol)
Temperature[10]
(K)
Radius
(R)
Mass
(M)
1NE O3.5 If* −10.0 42,000 17 74
1SW O4 III −9.8 41,500 16 66
2 O5.5 V(f) −8.9 40,000 12 43
3 O8 V −7.7 33,400 9 25
10 O9 V −7.2 31,500 8 20
12 B1 V −5.3 30,000 4 11
13 O6.5 III((f)) −8.6 35,600 12 35
15 O8 V −7.8 33,400 10 25
16 O7.5 V −9.0 34,000 16 38
17 O3.5 III −10.1 42,700 17 78
18 B0.5 V −6.4 30,000 6 15
19 B0.5 V −5.4 30,000 4 11

G353.2+0.7[edit]

The young stellar cluster G353.2+0.7 lies east of Pismis 24 and was revealed by a Chandra X-ray image showing approximately 800 stars.[11]

G353.1+0.36[edit]

The young stellar cluster G353.1+0.36 lies southeast of Pismis 24 and also contains approximately 800 stars detected by X-ray.[11] The region includes several O-type stars, including [BDSB2003] 10.[12]

References[edit]

  1. ^ a b c "SIMBAD Astronomical Database". Results for NGC 6357. Retrieved 2007-05-03. 
  2. ^ Robert Nemiroff; Jerry Bonnell (21 November 2010). "A Massive Star in NGC 6357". Astronomy Picture of the Day. 
  3. ^ R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN 0-933-34651-4. 
  4. ^ a b http://www.theguardian.com/science/2013/feb/20/lobster-nebula-birthplace-stars-infrared
  5. ^ http://www.space.com/19938-lobster-nebula-seen-with-esos-vista-telescope-space-wallpaper.html
  6. ^ "2MASS Picture of the Week Archive Captions". 
  7. ^ "ESA Science & Technology: Star on a Hubble diet NGC 6357". Retrieved 2007-04-11. 
  8. ^ NASA: Massive Stars in Open Cluster Pismis 24, 2006
  9. ^ Fang, M.; Van Boekel, R.; King, R. R.; Henning, T.; Bouwman, J.; Doi, Y.; Okamoto, Y. K.; Roccatagliata, V.; Sicilia-Aguilar, A. (2012). "Star formation and disk properties in Pismis 24". Astronomy & Astrophysics 539: A119. arXiv:1201.0833. Bibcode:2012A&A...539A.119F. doi:10.1051/0004-6361/201015914.  edit
  10. ^ Martins, F.; Schaerer, D.; Hillier, D. J. (2005). "A new calibration of stellar parameters of Galactic O stars". Astronomy and Astrophysics 436 (3): 1049. arXiv:astro-ph/0503346. Bibcode:2005A&A...436.1049M. doi:10.1051/0004-6361:20042386.  edit
  11. ^ a b Townsley, L. K. et al. (2014). "The Massive Star-Forming Regions Omnibus X-Ray Catalog". Astrophysical Journal Supplement 213 (1): 1. arXiv:1403.2576. Bibcode:2014ApJS..213....1T. doi:10.1088/0067-0049/213/1/1. 
  12. ^ Damke, G. et al. (2006). "The open cluster G353.1+0.7 in NGC6357". Revista Mexicana de Astronomía y Astrofísica 26: 180. Bibcode:2006RMxAC..26..180D. 

External links[edit]

  1. A Massive Star in NGC 6357 with a close-up of Pismis 24.
  2. Star Forming Region NGC 6357 showing complex interactions between interstellar winds, radiation pressures and magnetic fields.
  3. NGC 6357: Massive Stars
  4. A Massive Star in NGC 6357