Spitzer IRS Spectra and Envelope Models of Class I Protostars in Taurus

TL;DR

This study analyzes Spitzer IRS spectra of 28 Class I protostars in Taurus, revealing diverse envelope properties and providing insights into their initial collapse conditions.

Contribution

It presents new IRS spectra and envelope models for Class I protostars, highlighting the diversity in their envelope parameters and initial conditions.

Findings

Wide range of envelope densities and centrifugal radii.

Most spectral energy distributions well-constrained by IRS data.

Diverse initial conditions for protostellar collapse inferred.

Abstract

We present Spitzer Infrared Spectrograph spectra of 28 Class I protostars in the Taurus star-forming region. The 5 to 36 micron spectra reveal excess emission from the inner regions of the envelope and accretion disk surrounding these predecessors of low-mass stars, as well as absorption features due to silicates and ices. Together with shorter- and longer-wavelength data from the literature, we construct spectral energy distributions and fit envelope models to 22 protostars of our sample, most of which are well-constrained due to the availability of the IRS spectra. We infer that the envelopes of the Class I objects in our sample cover a wide range in parameter space, particularly in density and centrifugal radius, implying different initial conditions for the collapse of protostellar cores.