Confirmation of the VeLLO L1148-IRS: Star formation at very low (column) density

Abstract

We report the detection of a compact (~5 arcsec; about 1800au projected size) CO outflow from L1148-IRS. This confirms that this Spitzer source is physically associated with the nearby (≈325pc) L1148 dense core. Radiative transfer modelling suggests an internal luminosity of 0.08to0.13L⊙. This validates L1148-IRS as a Very Low Luminosity Object (VeLLO; L≤ 0.1L⊙). The L1148 dense core has unusually low densities and column densities for a star-forming core. It is difficult to understand how L1148-IRS might have formed under these conditions. Independent of the exact final mass of this VeLLO (which is likely <0.24M⊙), L1148-IRS and similar VeLLOs might hold some clues about the isolated formation of brown dwarfs. © 2011 California Institute of Technology. Monthly Notices of the Royal Astronomical Society © 2011 RAS.