A Spitzer Detection of Crystalline Silicates in a Protostar
First Author:
CharlesA. Poteet
Email: cpoteet AT physics.utoledo.edu
The University of Toledo
2801 W. Bancroft Street
Toledo, OH, 43606, USA
Coauthors:
Megeath, S. Thomas, The University of Toledo
Watson, Dan W., University of Rochester
McClure, Melissa, University of Michigan
Calvet, Nuria, University of Michigan
Allen, Lori, CfA
Furlan, Elise, JPL
Hartmann, Lee, University of Michigan
Muzerolle, James, Steward Observatory
Abstract
Recent surveys with the Spitzer Space Telescope have systematically identified protostars in nearby molecular clouds. The richest sample of protostars within 500 pc of the Sun is found in the Orion A molecular cloud, where we have observed 252 protostars with the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope. Here, we present the IRS spectrum of the Orion A protostar 8385127-5141. The mid-infrared spectrum reveals the discovery of crystalline substructure in the amorphous silicate absorption features. Crystalline silicates are often observed as infrared emission features around the circumstellar disk of Herbig Ae/Be stars and T-Tauri stars, but this is only the second instance of crystalline features being detected in the envelope of a protostar, and it is to our knowledge, the first instance of these absorption features being observed in a protostar with Spitzer. Using radiative transfer models, we investigate the nature of the central protostar and its envelope structure, as well as discuss the implications of crystalline silicates in the protostellar environment.
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