Spitzer Observations of Bok Globule B335: Isolated Star Formation Efficiency and Cloud Structure

TL;DR

This study combines infrared and millimeter observations to analyze the structure and star formation efficiency of the isolated Bok globule B335, revealing a small protostar within a flattened core consistent with collapse models.

Contribution

It provides detailed measurements of B335's density profile, core structure, and protostar mass, offering insights into isolated star formation processes.

Findings

Protostar mass is about 5% of the globule mass.

Detected a flattened molecular core aligned with the circumstellar disk.

Confirmed core structure consistent with collapse simulations.

Abstract

We present infrared and millimeter observations of Barnard 335, the prototypical isolated Bok globule with an embedded protostar. Using Spitzer data we measure the source luminosity accurately; we also constrain the density profile of the innermost globule material near the protostar using the observation of an 8.0 um shadow. HHT observations of 12CO 2 --> 1 confirm the detection of a flattened molecular core with diameter ~10000 AU and the same orientation as the circumstellar disk (~100 to 200 AU in diameter). This structure is probably the same as that generating the 8.0 um shadow and is expected from theoretical simulations of collapsing embedded protostars. We estimate the mass of the protostar to be only ~5% of the mass of the parent globule.