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Spitzer Space Telescope spectroscopy of ices toward low-mass embedded protostars

Boogert, A. C. Andwin and Pontoppidan, Klaus M. and Lahuis, Fred and Jorgensen, Jes K. and Augereau, Jean-Charles and Blake, Geffrey A. and Brooke, Timothy Y. and Brown, Joanna and Dullemond, C. P. and Evans, Neal J. and Geers, Vincent and Hogerheijde, Michiel R. and Kessler-Silacci, Jacqueline and Knez, Claudia and Morris, Pat and Noriega-Crespo, Alberto and Schoier, Fredrik L. and van Dishoeck, Ewine F. and Allen, Lori E. and Harvey, Paul M. and Koerner, David W. and Mundy, Lee G. and Myers, Philip C. and Padgett, Deborah L. and Sargent, Anneila I. and Stapelfeldt, Karl R. (2004) Spitzer Space Telescope spectroscopy of ices toward low-mass embedded protostars. Astrophysical Journal Supplement Series, 154 (1). pp. 359-362. ISSN 1538-4365


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Publisher’s or external URL: http://dx.doi.org/10.1086/422556


Sensitive 5-38 μm Spitzer Space Telescope and ground-based 3-5 μm spectra of the embedded low-mass protostars B5 IRS1 and HH 46 IRS show deep ice absorption bands superposed on steeply rising mid-infrared continua. The ices likely originate in the circumstellar envelopes. The CO2 bending mode at 15 μm is a particularly powerful tracer of the ice composition and processing history. Toward these protostars, this band shows little evidence for thermal processing at temperatures above 50 K. Signatures of lower temperature processing are present in the CO and OCN- bands, however. The observed CO2 profile indicates an intimate mixture with H2O, but not necessarily with CH3OH, in contrast to some high-mass protostars. This is consistent with the low CH3OH abundance derived from the ground-based L-band spectra. The CO2: H2O column density ratios are high in both B5 IRS1 and HH 46 IRS (similar to35%). Clearly, the Spitzer spectra are essential for studying ice evolution in low-mass protostellar environments and for eventually determining the relation between interstellar and solar system ices.

Item Type: Article
ID number or DOI: 10.1086/422556
Keywords: abundance; astrochemistry; CO; cores; dust; envelopes; infrared : ISM; interstellar ices; ISM : abundances; ISM : molecules; Stars; stars : formation; stars : individual (B5 IRS 1)
Subjects: Q Science > QB Astronomy
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > Physics and Astronomy
Date Deposited: 30 Sep 2015 04:55
URI: http://openknowledge.nau.edu/id/eprint/109

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