skip to main content


The NSF Public Access Repository (NSF-PAR) system and access will be unavailable from 10:00 PM ET on Friday, December 8 until 2:00 AM ET on Saturday, December 9 due to maintenance. We apologize for the inconvenience.

Search for: All records

Creators/Authors contains: "Heimsoth, Daniel J."

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Free, publicly-accessible full text available November 1, 2024
  2. Abstract We present a comprehensive analysis of the evolution of envelopes surrounding protostellar systems in the Perseus molecular cloud using data from the MASSES survey. We focus our attention to the C 18 O(2–1) spectral line, and we characterize the shape, size, and orientation of 54 envelopes and measure their fluxes, velocity gradients, and line widths. To look for evolutionary trends, we compare these parameters to the bolometric temperature T bol , a tracer of protostellar age. We find evidence that the angular difference between the elongation angle of the C 18 O envelope and the outflow axis direction generally becomes increasingly perpendicular with increasing T bol , suggesting the envelope evolution is directly affected by the outflow evolution. We show that this angular difference changes at T bol = 53 ± 20 K, which includes the conventional delineation between Class 0 and I protostars of 70 K. We compare the C 18 O envelopes with larger gaseous structures in other molecular clouds and show that the velocity gradient increases with decreasing radius ( ∣  ∣ ∼ R − 0.72 ± 0.06 ). From the velocity gradients we show that the specific angular momentum follows a power-law fit J / M ∝ R 1.83±0.05 for scales from 1 pc down to ∼500 au, and we cannot rule out a possible flattening out at radii smaller than ∼1000 au. 
    more » « less