Abstract
Very Low Luminosity Objects (VeLLOs) are the faintest protostars with intrinsic luminosity Lint ≦ 0.1 L⊙. Their low luminosities hints that they could be either very young, very low-mass, or even very young and low-mass protostars (i.e., proto brown dwarfs). Thus, identifying VeLLOs and investigating their properties are crucial for fully understanding of the earliest stage of star formation. The goal of this paper is to uncover VeLLOs in the Taurus molecular cloud and confirm that they are true Young Stellar Objects (YSOs). We use the catalogue from Taurus Spitzer Legacy Project and apply the selection criteria developed by Dunham et al. (2008) which are based on the Spectral Energy Distributions (SEDs) of typical Class 0 and early Class I protostars. New criteria for bolometric temperature and extinction are included to make up the lack of complete coverage of submm/mm maps in Taurus. As a result, we select 10 VeLLO candidates. In order to verify our VeLLO candidates are real YSOs, we observe 13CO (J=2-1), C18O (J=1-0), N2D+ (J=2-1), N2D+ (J=3-2), and N2H+(J=1-0) with Arizona Radio Observatory (ARO). We detect N2H+ and N2D+ (J=2-1) in four VeLLO candidates and 13CO and C18O in all 10 VeLLO candidates (except SL05). We have also obtained SMA CO (J=2-1) maps toward the four VeLLOs with N2H+ and N2D+ detections to investigate their outflow properties. Based on the result of the N2D+/N2H+ column density ratio, two VeLLO candidates could be very young protostars and the other eight are more likely to be very low-mass protostars.