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 an unbiased census of starless cores in Perseus, Serpens, andOphiuchus, assembled by comparing large-scale Bolocam 1.1 mm continuum emissionmaps with Spitzer c2d surveys. We use the c2d catalogs to separate 108 starlessfrom 92 protostellar cores in the 1.1 mm core samples from Enoch et al. (2006),Young et al. (2006), and Enoch et al. (2007). A comparison of these populationsreveals the initial conditions of the starless cores. Starless cores in Perseushave similar masses but larger sizes and lower densities on average thanprotostellar cores, with sizes that suggest density profiles substantiallyflatter than r^-2. By contrast, starless cores in Serpens are compact and havelower masses than protostellar cores; future star formation will likely resultin lower mass objects than the currently forming protostars. Comparison todynamical masses estimated from the NH_3 survey of Perseus cores by Rosolowskyet al. (2007) suggests that most of the starless cores are likely to begravitationally bound, and thus prestellar. The combined prestellar core massdistribution includes 108 cores and has a slope of -2.3+/-0.4 for M>0.8 Msun.This slope is consistent with recent measurements of the stellar initial massfunction, providing further evidence that stellar masses are directly linked tothe core formation process. We place a lower limit on the core-to-starefficiency of 25%. There are approximately equal numbers of prestellar andprotostellar cores in each cloud, thus the dense prestellar core lifetime mustbe similar to the lifetime of embedded protostars, or 4.5x10^5 years, with atotal uncertainty of a factor of two. Such a short lifetime suggests a dynamic,rather than quasi-static, core evolution scenario, at least at the relativelyhigh mean densities (n>2x10^4 cm^-3) to which we are sensitive.

The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus