Cepheus B

Cepheus B
Molecular cloud
Image of Cepheus B. The Cepheus OB3 association is the group of stars north out of frame.
Observation data: J2000 epoch
Right ascension22h 57m 7.00s
Declination+62° 37′ 22.3″
Distance~2,400 ly
ConstellationCepheus
Designations[BSM2002] 22551+6221 1, JCMTSE J225707.2+623726, JCMTSF J225707.2+623726, Cep B, Cepheus B Cloud
See also: Lists of nebulae

Cepheus B (Cep B) is a molecular cloud and star-forming region located about 2,400 ly away in the constellation Cepheus. The H II region Sh 2-155 is a component of this molecular cloud.

The cloud features a central spin-like filamentary structure and a bright core at its northern tip, which also contains Sh 2-155. Hot material within the molecular cloud like the [C II] emission and ¹³CO/C¹⁸O ratios seem to be affected on large scales by a gradual change mostly originating from the Sh 2-155 H II region via material photoevaporation from the molecular cloud. One study found that radiative star formation might work only on small scales and cannot explain large-scale star birth. Another study found that the density and temperature at the edge of the cloud are higher than at the center, suggesting that radiation-driven star formation does occur in Cepheus B on large scales.

A study identified approximately 400, 1 million year old pre-main-sequence (PMS) stars, 354 of which possess circumstellar disks. These younger disk-bearing stars are concentrated around the core of the molecular cloud while older stars are dispersed north in the direction of the O7-type star HD 217086, these stars are 3 to 5 million years old with 30% retaining disks. These PMS stars are concentrated in two major clusters, the Cepheus OB3b association containing 321 stars and an embedded cluster of 64 stars. Another ~400 PMS stars are all grouped into multiple small obscured and unobscured clusters throughout Cepheus B.

The previously mentioned long filamentary structure that extends from the head to the bottom like a spine is fragmenting due to gravity, though this is regulated by the magnetic fields (B-fields) of other nearby objects. The bright core in the north appears to resist the direct compression from the ionization front of the filamentary structure, maintaining its structural integrity. Observations indicate that the edge of the hotspot features a blister that has created a cavity, a near-IR star at the center of the blister is responsible for heating the hotspot. The hotspot triggers the formation of nearby star clusters without the need for OB stars exploding. The temperature of the molecular cloud is 70K in the west down to 40K in the east.

References

  1. 1 2 3 "Cep B". simbad.cds.unistra.fr.
  2. 1 2 Mookerjea, B.; Ossenkopf, V.; Ricken, O.; Güsten, R.; Graf, U. U.; Jacobs, K.; Kramer, C.; Simon, Rm; Stutzki, J. (June 2012). "The structure of hot gas in Cepheus B". Astronomy and Astrophysics. 542: L17. arXiv:1203.0811. Bibcode:2012A&A...542L..17M. doi:10.1051/0004-6361/201218923. L17.
  3. ↑ Sun, K.; Kramer, C.; Ungerechts, H.; Ossenkopf, V.; Müller, H.; Mookerjea, B.; Röllig, M.; Stutzki, J. (2008). "A Multiline Study of the Cepheus B Cloud". EAS Publications Series. 31: 209–210. Bibcode:2008EAS....31..209S. doi:10.1051/eas:0831048.
  4. ↑ Mookerjea, B.; Kramer, C.; Röllig, M.; Masur, M. (September 2006). "Study of photon dominated regions in Cepheus B". Astronomy and Astrophysics. 456 (1): 235–244. arXiv:astro-ph/0606268. Bibcode:2006A&A...456..235M. doi:10.1051/0004-6361:20064991.
  5. ↑ Beuther, H.; Kramer, C.; Deiss, B.; Stutzki, J. (October 2000). "CO mapping and multi-line-analysis of Cepheus B". Astronomy and Astrophysics. 362: 1109–1121. Bibcode:2000A&A...362.1109B.
  6. ↑ Chen, Sheng; Huang, Maohai (August 2010). "Radiation-driven implosion in the Cepheus B molecular cloud". Research in Astronomy and Astrophysics. 10 (8): 777–784. arXiv:1004.5171. Bibcode:2010RAA....10..777C. doi:10.1088/1674-4527/10/8/007.
  7. ↑ Bieging, John H.; Patel, Saahil; Hofmann, Ryan; Peters, William L.; Kainulainen, Jouni; Zhang, Miaomiao; Stutz, Amelia M. (October 2018). "The Arizona Radio Observatory CO Mapping Survey of Galactic Molecular Clouds. VI. The Cep OB3 Cloud (Cepheus B and C) in CO J = 2-1, 13CO J = 2-1, and CO J = 3-2". The Astrophysical Journal Supplement Series. 238 (2): 20. Bibcode:2018ApJS..238...20B. doi:10.3847/1538-4365/aade01 (inactive 6 November 2026). 20.{{cite journal}}: CS1 maint: DOI inactive as of November 2026 (link)
  8. ↑ Getman, Konstantin V.; Feigelson, Eric D.; Luhman, Kevin L.; Sicilia-Aguilar, Aurora; Wang, Junfeng; Garmire, Gordon P. (July 2009). "Protoplanetary Disk Evolution Around the Triggered Star-Forming Region Cepheus B". The Astrophysical Journal. 699 (2): 1454–1472. arXiv:0904.4907. Bibcode:2009ApJ...699.1454G. doi:10.1088/0004-637X/699/2/1454.
  9. ↑ Wang, Jungfeng; Bouwman, Jeroen; Feigelson, Eric; Getman, Konstantin; Lawson, Warrick; Linz, Hendrik; Luhman, Kevin; Sicilia-Aquilar, Aurora (May 2006). "Protoplanetary Disks among X-ray Selected Young Stars in Cepheus B". Spitzer Proposal ID 30361: 30361. Bibcode:2006sptz.prop30361W.
  10. ↑ Getman, Konstantin V.; Feigelson, Eric D.; Townsley, Leisa; Broos, Patrick; Garmire, Gordon; Tsujimoto, Masahiro (April 2006). "Chandra Study of the Cepheus B Star-forming Region: Stellar Populations and the Initial Mass Function". The Astrophysical Journal Supplement Series. 163 (2): 306–334. arXiv:astro-ph/0601405. Bibcode:2006ApJS..163..306G. doi:10.1086/501453.
  11. ↑ Sandhyarani, Panigrahy; Eswaraiah, Chakali; Samal, Manash R.; Rawat, Vineet; Hwang, Jihye; Wang, Jia-Wei; Ma, Yuehui; Sanhueza, Patricio; Jose, Jessy (July 2026). "Magnetic field topology and star formation in the Cepheus B filamentary cloud under external feedback". Monthly Notices of the Royal Astronomical Society. 549 (4) stag1034: 1–17. arXiv:2605.26810. Bibcode:2026MNRAS.549g1034S. doi:10.1093/mnras/stag1034. stag1034.
  12. ↑ Olmi, L.; Felli, M. (November 1998). "CS observations of the hotspot at the S 155/Cepheus B interface". Astronomy and Astrophysics. 339: 872–879. Bibcode:1998A&A...339..872O.
  13. ↑ Testi, L.; Olmi, L.; Hunt, L.; Tofani, G.; Felli, M.; Goldsmith, P. (1995). "Sequential star formation in the Cepheus molecular cloud: the S 155/Cepheus B interface". Astronomy and Astrophysics. 303: 881. Bibcode:1995A&A...303..881T.
  14. ↑ Gordon, M. A. (April 1990). "Continuum Emission from the Star-forming Regions Cepheus A and B". Astrophysical Journal. 352: 636. Bibcode:1990ApJ...352..636G. doi:10.1086/168566.
  15. ↑ Deiss, B. M.; Beuther, H.; Kramer, C. (September 1999). "Temperature gradients in the Cepheus B molecular cloud - a multi-line analysis". Abstracts of Contributed Talks and Posters presented at the Annual Scientific Meeting of the Astronomische Gesellschaft, in Goettingen. 15: 20–25. Bibcode:1999AGAb...15...98D.