English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present a search for all embedded protostars with internal luminosities <1 solar luminosity in the sample of nearby, low-mass star-forming regionssurveyed by the Spitzer Space Telescope c2d Legacy Project. The internalluminosity (Lint) of a source is the luminosity of the central source andexcludes luminosity arising from external heating. On average, the c2d data aresensitive to embedded protostars with Lint > 4E-3 (d/140 pc)^2 solarluminosities, a factor of 25 better than the sensitivity of IRAS to suchobjects. We present selection criteria used to identify candidates from theSpitzer data and examine complementary data to decide whether each candidate istruly an embedded protostar. We find a tight correlation between the 70 micronflux and internal luminosity of a protostar, an empirical result based onobservations and two-dimensional radiative transfer models of protostars. Weidentify 50 embedded protostars with Lint < 1 solar luminosities; 15 have Lint< 0.1 solar luminosities. The intrinsic distribution of source luminositiesincreases to lower luminosities. While we find sources down to the abovesensitivity limit, indicating that the distribution may extend to luminositieslower than probed by these observations, we are able to rule out a continuedrise in the distribution below 0.1 solar luminosities. Between 75-85% of coresclassified as starless prior to being observed by Spitzer remain starless toour luminosity sensitivity; the remaining 15-25% harbor low-luminosity,embedded protostars. We compile complete Spectral Energy Distributions for all50 objects and calculate standard evolutionary signatures, and argue that theseobjects are inconsistent with the simplest picture of star formation whereinmass accretes from the core onto the protostar at a constant rate.

Identifying the Low Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores