Confirmation of the VeLLO L1148-IRS: Star Formation at very low (Column) Density

TL;DR

This paper confirms the existence of a VeLLO, L1148-IRS, with a low luminosity and outflow, in a very low-density core, providing insights into star formation at minimal densities and potential brown dwarf origins.

Contribution

It reports the detection and characterization of a VeLLO in an unusually low-density core, highlighting star formation processes at very low column densities.

Findings

Detection of a CO outflow from L1148-IRS.

L1148-IRS has an internal luminosity of 0.08-0.13 L_sun.

L1148 dense core exhibits unusually low densities.

Abstract

We report the detection of a compact (of order 5 arcsec; about 1800 AU projected size) CO outflow from L1148-IRS. This confirms that this Spitzer source is physically associated with the nearby (about 325 pc) L1148 dense core. Radiative transfer modeling suggests an internal luminosity of 0.08 to 0.13 L_sun. This validates L1148-IRS as a Very Low Luminosity Object (VeLLO; L < 0.1 L_sun). 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 < 0.24 M_sun), L1148-IRS and similar VeLLOs might hold some clues about the isolated formation of brown dwarfs.