Dynamical and chemical properties of the “starless” core L1014

¹ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
² Università degli Studi di Firenze, Dipartimento di Astronomia e Scienza dello Spazio, Largo E. Fermi 5, 50125 Firenze, Italy e-mail: crapsi@arcetri.astro.it
³ University of Texas at Austin, 1 University Station C1400, Austin, TX 78712-0259, USA
⁴ Leiden Observatory, PO Box 9513, 2300 RA Leiden, The Netherlands
⁵ Max-Planck-Institut für Radioastronomie (MPIfR), Bonn, Germany
⁶ Korea Astronomy and Space Science Institute, 61-1 Hwaam-dong, Yusung-gu, Daejon 305-348, Korea
⁷ National Radio Astronomical Observatory, PO Box 0, Socorro, NM 87801, USA

Received: 22 November 2004
Accepted: 28 January 2005

Abstract

Spitzer Space Telescope observations of a point-like source, L1014-IRS, close to the dust peak of the low-mass dense core L1014, have raised questions about its starless nature. These show the presence of an object with colors expected for an embedded protostar with the implication that L1014-IRS would be the lowest luminosity isolated protostar known, and an ideal target with which to test star formation theories at the low mass end.
In order to study its molecular content and to search for the presence of a molecular outflow, we mapped L1014 in at least one transition of ¹²CO, N₂H⁺ , HCO⁺ , CS, and of their isotopologues ¹³CO, C¹⁸O, C¹⁷O, N₂D⁺ , and H¹³CO⁺ , using the Five College Radio Astronomy Observatory (FCRAO), the IRAM 30 m antenna, and the Caltech Submillimeter Observatory (CSO). The data show physical and chemical properties in L1014 typical of moderately evolved dense cores: i.e. H₂  central density of a few 10⁵ molecules cm^-3 , estimated mass of ~2 , CO integrated depletion factor less than 10, N(N₂H⁺  cm^-2 , N(N₂D⁺)/N(N₂H⁺) equal to 10%, and relatively broad N₂H⁺  and N₂D⁺  lines (0.35 km s^-1 ). Infall signatures and significant velocity shifts between optically thick and optically thin tracers are not observed in the line profiles.
No classical signatures of molecular outflow are found in the ¹²CO and ¹³CO FCRAO observations. In particular, no high velocity wings are found, and no well-defined blue-red lobes of ¹²CO emission are seen in the channel maps. Sensitive, higher resolution observations will clarify the presence of a molecular outflow on a smaller scale than that probed by our observations.