Star formation in the luminous YSO IRAS 18345-0641

¹ Joint Astronomy Centre, 660 N. Aohoku Pl., Hilo, HI-96720, USA
e-mail: w.varricatt@jach.hawaii.edu
² Astrophysics Research Institute, Liverpool John Moores University, Birkenhead, Wirral, CH41 1LD, UK
³ ESO, Karl-Schwarzschild-Str. 2, 85748 Garching b. München, Germany

Received: 10 January 2013
Accepted: 8 April 2013

Abstract

Aims. We aim to understand the star formation associated with the luminous young stellar object (YSO) IRAS 18345-0641 and to address the complications arising from unresolved multiplicity in interpreting the observations of massive star-forming regions.

Methods. New infrared imaging data at sub-arcsec spatial resolution are obtained for IRAS 18345-0641. The new data are used along with mid- and far-IR imaging data, and CO (J = 3−2) spectral line maps downloaded from archives to identify the YSO and study the properties of the outflow. Available radiative-transfer models are used to analyze the spectral energy distribution (SED) of the YSO.

Results. Previous tentative detection of an outflow in the H₂ (1–0) S1 line (2.122 μm) is confirmed through new and deeper observations. The outflow appears to be associated with a YSO discovered at infrared wavelengths. At high angular resolution, we see that the YSO is probably a binary. The CO (3–2) lines also reveal a well defined outflow. Nevertheless, the direction of the outflow deduced from the H₂ image does not agree with that mapped in CO. In addition, the age of the YSO obtained from the SED analysis is far lower than the dynamical time of the outflow. We conclude that this is probably caused by the contributions from a companion. High-angular-resolution observations at mid-IR through mm wavelengths are required to properly understand the complex picture of the star formation happening in this system, and generally in massive star forming regions, which are located at large distances from us.