Encyclopedia

compact H II region

compact H II region

[′käm‚pakt ′āch ′tü ‚rē·jən]
(astronomy)
A region of dense ionized hydrogen in interstellar space, not greater than 1 parsec (1.9 × 1013 miles or 3.1 × 1013 kilometers) in diameter.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive
Compact H II regions have densities [??]5 x [10.sup.3] [cm.sup.3], sizes of [??]0.5 pc, ionized gas mass of ~1 [M.sub.[dot encircle]], and EM [??] [10.sup.7] pc [cm.sup.-6] while ultracompact H II regions have sizes of [??] 0.1 pc, and thermal electron densities of [??][10.sup.4] [cm.sup.3], mass of ionized gas of ~[10.sup.-2] [M.sub.[dot encircle]], and EM [??] [10.sup.7] pc [cm.sup.-6] [2, 3].
Israel, "Compact H II regions and OB star formation," Annual Review of Astronomy and Astrophysics, vol.
Habing, "Compact H II regions near the OH source ON-2," Astronomy & Astrophysics, vol.
[HCO.sup.+] and radio continuum emission from the star forming region G75.78+0.34
Copyright © 2003-2025 Farlex, Inc Disclaimer
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.