Jump to content

Embedded cluster

From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by Tdslk (talk | contribs) at 00:25, 10 October 2017 (removed copy edit tag). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
X-ray view of Orion showing the Trapezium embedded cluster.

Embedded stellar clusters, or simply embedded clusters (EC), are open clusters that are still surrounded by their progenitor molecular cloud.[1] They are often areas of active star formation, giving rise to stellar objects that have similar ages and compositions.[2] Because of the dense material that surrounds the stars, they cannot be observed in visible light but are detectable using other sections of the electromagnetic spectrum, such as the near-infrared and X-rays. In these spectra, they are often detected as stellar enhancements above expected galactic background stellar counts.

The sizes of stellar objects born in embedded clusters are distributed according to initial mass function with a universal ratio between low- and high-mass stars. Many ultra-compact H II regions, the precursors to massive protostars, are associated with embedded clusters.[2]

Over time, radiation pressure from the stellar objects will disperse the molecular cloud and give rise to the better known open cluster.

Although many embedded stellar clusters are known to exist, few have specified names. Named possible embedded star clusters include:

  1. Trapezium cluster
  2. Rho Ophiuchi cloud complex
  3. IRAS 06068+2030
  4. IRAS 06155+2319
  5. IRAS 22551+6621
  6. IRAS 22172+5549
  7. IRAS 00070+5549

References

  1. ^ Lada, Charles J.; Lada, Elizabeth A. (2004), "Embedded clusters in molecular clouds", Annual Review of Astronomy and Astrophysics, 41: 57–115, arXiv:astro-ph/0301540, doi:10.1146/annurev.astro.41.011802.094844
  2. ^ a b Clerkin, James (2004), 2MASS study of candidate precursors to UCHII regions, Universidade do Porto {{citation}}: |access-date= requires |url= (help)