Mid-infrared observations of young stellar objects in the vicinity of Orionis*
Astrophysics Group, School of Chemistry & Physics, Keele University, Staffordshire ST5 5BG, UK
Corresponding author: J. M. Oliveira, firstname.lastname@example.org
Accepted: 26 January 2004
We present new mid-infrared observations of objects in the vicinity of the O-star σ Orionis, obtained with TIMMI-2 at ESO. By constraining their near- and mid-infrared spectral energy distributions, we established the nature of previously known IRAS sources and identified new mid-infrared sources as young stellar objects with circumstellar disks, likely massive members of the σ Ori cluster. For two of these objects we have obtained spectroscopy in the 8–13 μm range in order to investigate the chemistry of the dust grains. TX Ori exhibits a typical silicate emission feature at 10 μm, with a feature at about 11.2 μm that we identify as due to crystalline olivine. The IRAS 05358-0238 spectrum is very unusual, with a weak silicate feature and structure in the range 10–12 μm that may be explained as due to self-absorbed forsterite. We also provide the first evidence for the presence of circumstellar disks in the jet sources Haro 5-39/HH 447, V510 Ori/HH 444 and V603 Ori/HH 445.
Key words: stars: circumstellar matter / stars: pre-main sequence / stars: planetary systems: protoplanetary disks / infrared: stars / Galaxy: open clusters and associations: individual: σ Orionis
© ESO, 2004