How Starless Are Starless Cores?

TL;DR

This study reclassifies a dense core previously thought to be starless as a low-luminosity protostar, highlighting the importance of high-resolution surveys for accurate starless core census.

Contribution

It provides evidence that some cores classified as starless are actually protostars, refining estimates of core and protostar lifetimes.

Findings

Per-Bolo 45 hosts an embedded, low-luminosity protostar.

Starless core lifetime is overestimated by 4-18%.

Protostellar lifetime is underestimated by 5-20%.

Abstract

In this paper, we present the results of CARMA continuum and spectral line observations of the dense core Per-Bolo 45. Although this core has previously been classified as starless, we find evidence for an outflow and conclude that Per-Bolo 45 is actually an embedded, low-luminosity protostar. We discuss the impact of newly discovered, low-luminosity, embedded objects in the Perseus molecular cloud on starless core and protostar lifetimes. We estimate that the starless core lifetime has been overestimated by 4-18% and the Class 0/I protostellar lifetime has been underestimated by 5-20%. Given the relatively large systematic uncertainties involved in these calculations, variations on the order of 10% do not significantly change either core lifetimes or the expected protostellar luminosity function. Finally, we suggest that high resolution (sub)millimeter surveys of known cores lacking near-infrared and mid-infrared emission are necessary to make an accurate census of starless cores.