| Description |
Spitzer Space Telescope surveys of nearby, low-mass star-formingregions have discovered a new class of very low luminosity objects(VeLLOs), protostars embedded within dense cores with luminosities lessthan or equal to 0.1 Lsun. VeLLOs represent the extreme low end of theprotostellar luminosity distribution, which is comprised mainly of sourcesbelow about 1 Lsun. The standard model of star formation, which predictsa mass accretion rate constant with time, is inconsistent with such alarge population of low luminosity embedded protostars, leading numerousrecent authors to suggest that mass accretion is variable and/or episodicin nature. Further constraints on this mass accretion process requirefar-IR and submm data to fill in the gap between existing Spitzer mid-IRand ground-based millimeter continuum data. We propose to obtain HerschelPACS and SPIRE 100-500 micron photometry of 24 confirmed and candidateembedded protostars with L < 1.0 Lsun. With these data, we will: (1)calculate accurate evolutionary indicators, (2) provide essential inputsfor source models that seek to constrain the properties of both theprotostars and the dense cores in which they are embedded, and (3) confirmor reject candidates that have not been conclusively shown to be embeddedprotostars. The proposed observations will provide crucial data forfurther understanding the protostellar luminosity distribution and massaccretion process for a very modest (6.0 hours) allocation of observingtime. |
