Herschel/HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region
2010 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 521, L40- p.Article in journal (Refereed) Published
Herschel/HIFI observations of high-J lines (up to J(u) = 10) of (CO)-C-12, (CO)-C-13 and (CO)-O-18 are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS 4B, obtained as part of the Water In Star-forming regions with Herschel (WISH) key program. The spectrally-resolved HIFI data are complemented by ground-based observations of lower-J CO and isotopologue lines. The (CO)-C-12 10-9 profiles are dominated by broad (FWHM 25-30 km s(-1)) emission. Radiative transfer models are used to constrain the temperature of this shocked gas to 100-200 K. Several CO and (CO)-C-13 line profiles also reveal a medium-broad component (FWHM5-10 km s(-1)), seen prominently in H2O lines. Column densities for both components are presented, providing a reference for determining abundances of other molecules in the same gas. The narrow (CO)-O-18 9-8 lines probe the warmer part of the quiescent envelope. Their intensities require a jump in the CO abundance at an evaporation temperature around 25 K, thus providing new direct evidence for a CO ice evaporation zone around low-mass protostars.
Place, publisher, year, edition, pages
2010. Vol. 521, L40- p.
astrochemistry, stars: formation, ISM: jets and outflows, ISM: molecules
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:su:diva-51357DOI: 10.1051/0004-6361/201015119ISI: 000284150900040OAI: oai:DiVA.org:su-51357DiVA: diva2:384903
authorCount :632011-01-102011-01-102011-01-10Bibliographically approved