Abbreviated Journal Title

Astrophys. J.

Keywords

Circumstellar Matter; Ism: Abundances; Ism: Jets And Outflows; Open; Clusters And Associations: Individual (Taurus, Upper Scorpius); Stars:; Individual (2mass J17112318-2724315); Stars: Pre-Main Sequence; Young Stellar Objects; Silicate Dust; Pipe Nebula; Stars; Ices; Spectroscopy; Protostars; Taurus; Cores; Envelopes; Astronomy & Astrophysics

Abstract

We present near-infrared observations of the low-mass deeply embedded Class 0/I system 2MASS J17112318-2724315 (2M171123) in the B59 molecular cloud. Bright scattered light nebulosity is observed toward this source in the K(S) images, that seems to trace the edges of an outflow cavity. We report the detection of a low-luminosity protostar 2M17112255-27243448 (2M17112255) that lies similar to 8 '' (similar to 1000 AU) from 2M171123. This is a Class I system, as indicated by its 2-8 mu m slope and Infrared Array Camera colors, with an estimated internal luminosity of similar to 0.3 L(circle dot). We estimate a mass of similar to 0.12-0.25 M(circle dot) for this source, at an age of 0.1-1 Myr. Also presented is detailed modeling of the 2M171123 system. The best-fit parameters indicate a large envelope density of the order of similar to 10(-13) g cm(-3), and an intermediate inclination between 53 degrees and 59 degrees. The observed K(S)-band variability for this system could be explained by slight variability in the mass infall rate between 2.5E-5 and 1.8E-5 M(circle dot) yr(-1). The protostar 2M171123 exhibits a rarely observed absorption feature near 11.3 mu m within its 10 mu m silicate band. We find a strong correlation between the strength in this 11.3 mu m "edge" and the H(2)O-ice column density, indicating the origin of this feature in the thickness of the ice mantle over the silicate grains.

Journal Title

Astrophysical Journal

Volume

700

Issue/Number

2

Publication Date

1-1-2009

Document Type

Article

Language

English

First Page

1541

Last Page

1551

WOS Identifier

WOS:000268098100051

ISSN

0004-637X

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