Low-resolution spectroscopy and spectral energy distributions of selected sources towards sigma Orionis
Abbreviated Journal Title
stars: emission-line, Be; stars: low-mass, brown dwarfs; stars: pre-main; sequence; Galaxy: open clusters and associations: individual: sigma; Orionis; galaxies: quasars: emission lines; LOW-MASS STARS; ALPHA EMISSION STARS; XMM-NEWTON OBSERVATIONS; YOUNG; BROWN DWARFS; T-TAURI STARS; H-ALPHA; MAIN-SEQUENCE; ORI CLUSTER; OPTICAL SPECTROSCOPY; CANDIDATE MEMBERS; Astronomy & Astrophysics
Aims. We study in detail nine sources in the direction of the young sigma Orionis cluster, which is considered to be a unique site for studying stellar and substellar formation. The nine sources were selected because of their peculiar properties, such as extremely-red infrared colours or excessively strong H alpha emission for their blue optical colours. Methods. We acquired high-quality, low-resolution spectroscopy (R similar to 500) of the nine targets with ALFOSC at the Nordic Optical Telescope. We also re-analysed -band photometry from MIPS/Spitzer and compiled the highest quality photometric dataset available at the ViJHK(s) passbands and the four IRAC/Spitzer channels, for constructing accurate spectral energy distributions between 0.55 and 24 mu m. Results. The nine targets were classified into: one Herbig Ae/Be star with a scattering edge-on disc; two G-type stars; one X-ray flaring, early-M, young star with chromospheric H alpha emission; one very low-mass, accreting, young spectroscopic binary; two young objects at the brown-dwarf boundary with the characteristics of classical T Tauri stars; and two emission-line galaxies, one undergoing star formation, and another whose spectral energy distribution is dominated by an active galactic nucleus. We also discovered three infrared sources associated with overdensities in a cold cloud of the cluster centre. Conclusions. Low-resolution spectroscopy and spectral energy distributions are a vital tool for measuring the physical properties and evolution of young stars and candidates in the s Orionis cluster.
Astronomy & Astrophysics
"Low-resolution spectroscopy and spectral energy distributions of selected sources towards sigma Orionis" (2008). Faculty Bibliography 2000s. 165.