Molecular gas and star formation in Lynds 870 ^*

¹ Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, PR China
² National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China
³ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁴ Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, Taipei 106, Taiwan

Corresponding author: R. Q. Mao, rqmao@jets.pmo.ac.cn

Received: 17 October 2001
Accepted: 15 April 2002

Abstract

We present molecular line and submillimeter dust continuum observations of the Lynds 870 cloud in the vicinity of IRAS 20231+3440. Two submillimeter cores, SMM1 and SMM2, are identified mapping the 870 μm dust continuum and ammonia () emission. The total molecular mass is ~70–110 . The northern core is warmer and denser than the southern one. Molecular outflows are discovered in both cores. In the northern one a significant amount of low velocity (1.3–2.8 ) outflowing gas is found, that is hidden in the relatively broad CO lines but that is revealed by the narrower  spectra. While IRAS 20231+3440 is most likely the exciting star of the northern outflow, the driving source of the southern outflow is not detected by infrared surveys and must be deeply embedded in the cloud core. Large scale (~0.2 pc) infall motion is indicated by blue asymmetric profiles observed in the  J = 3–2 spectra. Red K_s band YSO candidates revealed by the 2MASS survey indicate ongoing star formation throughout the cloud. The calculated masses and the measured degree of turbulence are also reminiscent of clouds forming groups of stars. The excitation of the molecular lines, molecular abundances, and outflow properties are discussed. It is concluded that IRAS 20231+3440 is a Class I object, while the southern core most likely contains a Class 0 source.