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Title: A spectroscopic census in young stellar regions: the σ Orionis cluster

We present a spectroscopic survey of the stellar population of the σ Orionis cluster. We have obtained spectral types for 340 stars. Spectroscopic data for spectral typing come from several spectrographs with similar spectroscopic coverage and resolution. More than half of the stars in our sample are members confirmed by the presence of lithium in absorption, strong Hα in emission or weak gravity-sensitive features. In addition, we have obtained high-resolution (R ∼ 34,000) spectra in the Hα region for 169 stars in the region. Radial velocities were calculated from this data set. The radial velocity distribution for members of the cluster is in agreement with previous work. Analysis of the profile of the Hα line and infrared observations reveals two binary systems or fast rotators that mimic the Hα width expected in stars with accretion disks. On the other hand, there are stars with optically thick disks and narrow Hα profiles not expected in stars with accretion disks. This contribution constitutes the largest homogeneous spectroscopic data set of the σ Orionis cluster to date.
Authors:
; ;  [1] ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Centro de Investigaciones de Astronomía, Apdo. Postal 264, Mérida 5101-A (Venezuela, Bolivarian Republic of)
  2. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
  3. Cerro Tololo Interamerican Observatory, Casilla 603, La Serena (Chile)
  4. Depto. de Investigación en Física, Universidad de Sonora, Sonora (Mexico)
  5. Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, BC (Mexico)
  6. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
  7. Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States)
Publication Date:
OSTI Identifier:
22370500
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; COMPUTERIZED SIMULATION; DISTRIBUTION; EMISSION; GRAVITATION; LITHIUM; PROTOPLANETS; RADIAL VELOCITY; RESOLUTION; SPECTRA; STAR CLUSTERS; STARS