The Gould belt 'MISFITS' survey: the real solar neighborhood protostars.
HEIDERMAN A. and EVANS II N.J.
Abstract (from CDS):
We present an HCO+ J = 3 -> 2 survey of Class 0+I and Flat SED young stellar objects (YSOs) found in the Gould Belt clouds by surveys with Spitzer. Our goal is to provide a uniform Stage 0+I source indicator for these embedded protostar candidates. We made single point HCO+ J = 3 -> 2 measurements toward the source positions at the CSO and APEX of 546 YSOs (89% of the Class 0+I + Flat SED sample). Using the criteria from van Kempen et al., we classify sources as Stage 0+I or bona fide protostars and find that 84% of detected sources meet the criteria. We recommend a timescale for the evolution of Stage 0+I (embedded protostars) of 0.54 Myr. We find significant correlations of HCO+ integrated intensity with α and Tbol but not with Lbol. The detection fraction increases smoothly as a function of α and Lbol, while decreasing smoothly with Tbol. Using the Stage 0+I sources tightens the relation between protostars and high extinction regions of the cloud; 89% of Stage I sources lie in regions with AV > 8 mag. Class 0+I and Flat SED YSOs that are not detected in HCO+ have, on average, a factor of ∼2 higher Tbol and a factor of ∼5 lower Lbolthan YSOs with HCO+ detections. We find less YSO contamination, defined as the number of undetected YSOs divided by the total number surveyed, for sources with Tbol≲ 600 K and Lbol≳ 1 L☉. The contamination percentage is >90% at AV< 4 mag and decreases as AVincreases.
dust, extinction - galaxies: ISM - infrared: stars - ISM: clouds - galaxies: star formation
VizieR on-line data:
<Available at CDS (J/ApJ/806/231): table5.dat>