Super star cluster

A super star cluster (SSC) is a very massive young open cluster that is thought to be the precursor of a globular cluster.^[1] These clusters are referred to as "super" due to the fact that they are relatively much larger, more luminous, and contain more mass than other young star clusters.^[2] They typically contain a very large number of young, massive stars that ionize a surrounding H II region, similar to the Milky Way Galaxy's so-called "Ultra dense H II regions (UDHIIs)".^[3] An SSC's H II region is in turn surrounded by a cocoon of dust. In many cases, the stars and the H II regions will be invisible to optical observations due to high levels of extinction. As a result, the youngest SSCs are best observed in radio and infrared.^[4]

The Typical characteristics of SSCs:

large electron densities $n_{e}=10^{3}$ – $10^{6}$ cm $^{-3}$
pressures $P/$ $k_{b}$ $=10^{7}$ – $10^{10}$ K cm $^{-3}$ .^[4]
Mass $\gtrsim$ 5M_☉^[2]
Radius ≈ 5 pc ≈ $1.54^{19}$ cm^[2]
Age ≈ 100Myr^[2]

List

Name	Galaxy	Comments	Notes	Pictures
Westerlund 1 (Wd1)	Milky Way Galaxy	First SSC discovered in the Milky Way Galaxy.	^[5]	Westerlund 1
NGC 3603	Milky Way Galaxy		^[6]	$\NGC 3603$ NGC 3603
R136	Large Magellanic Cloud (LMC)	The prototype SSC	^[7]	R136 (Located in the Tarantula Nebula)
NGC 1569 A1 and A2	NGC 1569	Galaxy contains two SSCs	^[8]	NGC 1569

References

^ Gallagher; Grebel (2002). "Extragalactic Star Clusters: Speculations on the Future". Extragalactic Star Clusters, IAU Symposium. 207: 207. arXiv:astro-ph/0109052. Bibcode:2002IAUS..207..745G. {{cite journal}}: Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)
^ ^a ^b ^c ^d Johnson, Kelsey. "The Properties of Super Star Clusters In A Sample of Starburst Galaxies" (PDF). {{cite journal}}: Cite journal requires |journal= (help)
^ Kobulnicky, Henry A.; Johnson, Kelsey E. (1999). "Signatures of the Youngest Starbursts: Optically Thick Thermal Bremsstrahlung Radio Sources in Henize 2-10". ApJ. 527 (1): 154–166. arXiv:astro-ph/9907233. Bibcode:1999ApJ...527..154K. doi:10.1086/308075. {{cite journal}}: Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)
^ ^a ^b Johnson (2004). "Extragalactic Ultracompact HII Regions: Probing the Birth Environments of Super Star Clusters". ASP Conference Series. 527: 322. arXiv:astro-ph/0405125. Bibcode:2004ASPC..322..339J.
^ Clark, J. S.; Negueruela, I.; Crowther, P. A.; Goodwin, S. P. (2005). "On the massive stellar population of the super star cluster Westerlund 1". Astronomy and Astrophysics. 434 (3): 949. arXiv:astro-ph/0504342. Bibcode:2005A&A...434..949C. doi:10.1051/0004-6361:20042413.
^ Fukui, Y.; Ohama, A.; Hanaoka, N.; Furukawa, N.; Torii, K.; Dawson, J. R.; Mizuno, N.; Hasegawa, K.; Fukuda, T.; Soga, S.; Moribe, N.; Kuroda, Y.; Hayakawa, T.; Kawamura, A.; Kuwahara, T.; Yamamoto, H.; Okuda, T.; Onishi, T.; Maezawa, H.; Mizuno, A. (2014). "Molecular Clouds Toward the Super Star Cluster Ngc 3603; Possible Evidence for a Cloud-Cloud Collision in Triggering the Cluster Formation". The Astrophysical Journal. 780: 36. arXiv:1306.2090. Bibcode:2014ApJ...780...36F. doi:10.1088/0004-637X/780/1/36.
^ Massey, Philip; Hunter, Deidre A. (1998). "Star Formation in R136: A Cluster of O3 Stars Revealed by Hubble Space Telescope Spectroscopy". The Astrophysical Journal. 493: 180. Bibcode:1998ApJ...493..180M. doi:10.1086/305126.
^ Hunter, Deidre A.; O'Connell, Robert W.; Gallagher, J. S.; Smecker-Hane, Tammy A. (2000). "The Star Clusters in the Starburst Irregular Galaxy NGC 1569". The Astronomical Journal. 120 (5): 2383. arXiv:astro-ph/0009280. Bibcode:2000AJ....120.2383H. doi:10.1086/316810.

External links

Monster Super Star Cluster Discovered In Milky Way

[gallagher02-1] Gallagher; Grebel (2002). "Extragalactic Star Clusters: Speculations on the Future". Extragalactic Star Clusters, IAU Symposium. 207: 207. arXiv:astro-ph/0109052. Bibcode:2002IAUS..207..745G. {{cite journal}}: Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)

[:0-2] Johnson, Kelsey. "The Properties of Super Star Clusters In A Sample of Starburst Galaxies" (PDF). {{cite journal}}: Cite journal requires |journal= (help)

[kobulnicky99-3] Kobulnicky, Henry A.; Johnson, Kelsey E. (1999). "Signatures of the Youngest Starbursts: Optically Thick Thermal Bremsstrahlung Radio Sources in Henize 2-10". ApJ. 527 (1): 154–166. arXiv:astro-ph/9907233. Bibcode:1999ApJ...527..154K. doi:10.1086/308075. {{cite journal}}: Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)

[johnson04-4] Johnson (2004). "Extragalactic Ultracompact HII Regions: Probing the Birth Environments of Super Star Clusters". ASP Conference Series. 527: 322. arXiv:astro-ph/0405125. Bibcode:2004ASPC..322..339J.

[5] Clark, J. S.; Negueruela, I.; Crowther, P. A.; Goodwin, S. P. (2005). "On the massive stellar population of the super star cluster Westerlund 1". Astronomy and Astrophysics. 434 (3): 949. arXiv:astro-ph/0504342. Bibcode:2005A&A...434..949C. doi:10.1051/0004-6361:20042413.

[6] Fukui, Y.; Ohama, A.; Hanaoka, N.; Furukawa, N.; Torii, K.; Dawson, J. R.; Mizuno, N.; Hasegawa, K.; Fukuda, T.; Soga, S.; Moribe, N.; Kuroda, Y.; Hayakawa, T.; Kawamura, A.; Kuwahara, T.; Yamamoto, H.; Okuda, T.; Onishi, T.; Maezawa, H.; Mizuno, A. (2014). "Molecular Clouds Toward the Super Star Cluster Ngc 3603; Possible Evidence for a Cloud-Cloud Collision in Triggering the Cluster Formation". The Astrophysical Journal. 780: 36. arXiv:1306.2090. Bibcode:2014ApJ...780...36F. doi:10.1088/0004-637X/780/1/36.

[7] Massey, Philip; Hunter, Deidre A. (1998). "Star Formation in R136: A Cluster of O3 Stars Revealed by Hubble Space Telescope Spectroscopy". The Astrophysical Journal. 493: 180. Bibcode:1998ApJ...493..180M. doi:10.1086/305126.

[8] Hunter, Deidre A.; O'Connell, Robert W.; Gallagher, J. S.; Smecker-Hane, Tammy A. (2000). "The Star Clusters in the Starburst Irregular Galaxy NGC 1569". The Astronomical Journal. 120 (5): 2383. arXiv:astro-ph/0009280. Bibcode:2000AJ....120.2383H. doi:10.1086/316810.

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