A Spitzer-IRS Detection of Crystalline Silicates in a Protostellar Envelope release_afg7up42jrdw3m4cg2y7iqpkiu

by Charles A. Poteet, S. Thomas Megeath, Dan M. Watson, Nuria Calvet, Ian S. Remming, Melissa K. McClure, Benjamin A. Sargent, William J. Fischer, Elise Furlan, Lori E. Allen, Jon E. Bjorkman, Lee Hartmann, James Muzerolle, John J. Tobin (+1 others)

Released as a article .

2011  

Abstract

We present the Spitzer Space Telescope Infrared Spectrograph spectrum of the Orion A protostar HOPS-68. The mid-infrared spectrum reveals crystalline substructure at 11.1, 16.1, 18.8, 23.6, 27.9, and 33.6 microns superimposed on the broad 9.7 and 18 micron amorphous silicate features; the substructure is well matched by the presence of the olivine end-member forsterite. Crystalline silicates are often observed as infrared emission features around the circumstellar disks of Herbig Ae/Be stars and T Tauri stars. However, this is the first unambiguous detection of crystalline silicate absorption in a cold, infalling, protostellar envelope. We estimate the crystalline mass fraction along the line-of-sight by first assuming that the crystalline silicates are located in a cold absorbing screen and secondly by utilizing radiative transfer models. The resulting crystalline mass fractions of 0.14 and 0.17, respectively, are significantly greater than the upper limit found in the interstellar medium (< 0.02-0.05). We propose that the amorphous silicates were annealed within the hot inner disk and/or envelope regions and subsequently transported outward into the envelope by entrainment in a protostellar outflow
In text/plain format

Archived Files and Locations

application/pdf   278.8 kB
file_ig7j6efj3jh5lcx4fktgjqs7tm
archive.org (archive)
Read Archived PDF
Preserved and Accessible
Type  article
Stage   submitted
Date   2011-04-22
Version   v1
Language   en ?
arXiv  1104.4498v1
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: 4ef9c8dc-befc-4b2e-8383-17fa69e040d9
API URL: JSON