NGC 6357
Emission nebula
H II region
NGC 6357 composite image
Observation data: J2000 epoch
Right ascension17h 24m [1]
Declination−34° 20′[1]
Distance~5900±450[2] ly   (1800±140 pc)
ConstellationScorpius[3]
DesignationsWar and Peace Nebula,[1] Lobster Nebula [4] Sharpless 11, RCW 131, Gum 66, Madokami

NGC 6357 is a diffuse nebula near NGC 6334 in the constellation Scorpius. The nebula contains many proto-stars shielded by dark discs 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 given the name War and Peace Nebula by the Midcourse Space Experiment scientists because of its appearance, which, in infrared images the bright, western part resembles a dove, while the eastern part looks like a skull.[6] A petition by anime fans to rename it as the Madokami nebula, due to resemblance with a character, was unsuccessful.[7][8]

It is located about ~5,500 light years away from Earth.[9]

Associated open clusters

Pismis 24

A Hubble Space Telescope (HST) image of Pismis 24-1, the "core" of NGC 6357.
Dark Energy Camera captures the star-forming nebula NGC 6357

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 each, making them among the more massive stars on record.[10][11]

G353.2+0.7

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.[12]

G353.1+0.6

The young stellar cluster G353.1+0.6 lies southeast of Pismis 24 and also contains approximately 800 stars detected by X-ray.[12] The region includes several O-type stars, including [BDSB2003] 10.[13]

Massive stars

NGC 6357 is one of the most prominent sites of massive-star formation in our neighborhood of the Milky Way. A variety of early O-type stars reside in this nebula, blowing the bubbles around the star clusters that can be seen in the molecular cloud.

Prominent stars in Pismis 24[14]
Star name Spectral type Magnitude
(Mbol)		 Temperature[15]
(K)		 Radius
(R☉)		 Mass
(M☉)
WR 93 (HD 157504) WC7 -11.2 71,000 10 120
Pismis 24-1NEO3.5 If*−10.042,0001774
Pismis 24-1SWO4 III−9.841,5001666
Pismis 24-2O5.5 V(f)−8.940,0001243
Pismis 24-3O8 V−7.733,400925
Pismis 24-10O9 V−7.231,500820
Pismis 24-12B1 V−5.330,000411
Pismis 24-13O6.5 III((f))−8.635,6001235
Pismis 24-15O8 V−7.833,4001025
Pismis 24-16O7.5 V−9.034,0001638
Pismis 24-17O3.5 III−10.142,7001778
Pismis 24-18B0.5 V−6.430,000615
Pismis 24-19B0.5 V−5.430,000411

See also

References

  1. 1 2 3 "NGC 6357". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-05-03.
  2. ↑ Kuhn, Michael A.; Hillenbrand, Lynne A.; Sills, Alison; Feigelson, Eric D.; Getman, Konstantin V. (2018). "Kinematics in Young Star Clusters and Associations with Gaia DR2". The Astrophysical Journal. 870 (1): 32. arXiv:1807.02115. Bibcode:2019ApJ...870...32K. doi:10.3847/1538-4357/aaef8c. S2CID 119328315.
  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 978-0-933346-51-2.
  4. 1 2 Sample, Ian (20 February 2013). "Lobster Nebula – birthplace of stars – revealed in infrared". the Guardian.
  5. ↑ "Lobster Nebula Seen with ESO's VISTA Telescope Space Wallpaper". Space.com. 25 February 2013.
  6. ↑ "2MASS Picture of the Week Archive Captions".
  7. ↑ "There Is A New Petition To Name A Nebula After "Ultimate Madoka"". crunchyroll.com.
  8. ↑ "NGC 6357. The Lobster Nebula". astrodrudis.com.
  9. ↑ "Winter Wonderland' Glows in Space as Nebula Is Wreathed in Wintry Colors". Space.com. 20 December 2016.
  10. ↑ "ESA Science & Technology: Star on a Hubble diet NGC 6357". Archived from the original on 2007-04-04. Retrieved 2007-04-11.
  11. ↑ Nemiroff, R.; Bonnell, J., eds. (19 December 2006). "NASA: Massive Stars in Open Cluster Pismis 24". Astronomy Picture of the Day. NASA.
  12. 1 2 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. S2CID 76658453.
  13. ↑ 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.
  14. ↑ 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. S2CID 73612793.
  15. ↑ Martins, F.; Schaerer, D.; Hillier, D. J. (2005). "A new calibration of stellar parameters of Galactic O stars". Astronomy and Astrophysics. 436 (3): 1049–1065. arXiv:astro-ph/0503346. Bibcode:2005A&A...436.1049M. doi:10.1051/0004-6361:20042386. S2CID 39162419.
Wikimedia Commons has media related to NGC 6357.
  1. Star Forming Region NGC 6357 showing complex interactions between interstellar winds, radiation pressures and magnetic fields.
  2. A Massive Star in NGC 6357 with a close-up of Pismis 24.
  3. NGC 6357: Cathedral to Massive Stars
  4. A Massive Star in NGC 6357
  5. NGC 6357: Cathedral to Massive Stars
  6. NGC 6357: The Lobster Nebula
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