Star formation in the southern dark cloud DC 287.1+02.4

Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal e-mail: [yun;Pedro.Figueira]@oal.ul.pt

Received: 6 September 2005
Accepted: 23 February 2006

Abstract

Aims.We report the discovery of a group of 12 new infrared sources seen toward IRAS 10501-5630 and the southern dark globule DC 287.1+02.4. The globule appears as a round patch of extinction in optical images with a typical diameter of 5 arcmin.

Methods.The sources are seen on Ks and L' band images taken using SOFI at the NTT and ISAAC at the VLT. The globule was mapped in millimeter molecular transitions (CO(1–0), C¹⁸O(1–0), C¹⁸O(2–1), CS(2–1), HCN(1–0)) using the SEST telescope.

Results.Millimeter-wave spectroscopy revealed a single dense core seen in C¹⁸O, CS, and HCN, extending about 2 arcmin. The infrared sources are likely to be embedded in the dense cloud core. The reddest of the new infrared sources, named here DC 287.1+02.4 IRS, is not detected shortward of 2 μm, and it exhibits a very red  colour. The location and colour of this source suggest that this is the near-infrared counterpart of IRAS 10501-5630. Red nebular emission with an elongated shape is also seen in the H and  band images and could be due to scattered light originating in the embedded objects.