Spectroscopic characterization of X-ray emitting young stars associated with the Sh 2-296 nebula

Autor(es)

Fernandes, B. ^[1] ; Gregorio-Hetem, J. ^[1] ; Montmerle, T. ^[2] ; Rojas, G. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo - Brazil

^[2] Inst Astrophys, F-75014 Paris - France

^[3] Univ Fed Sao Carlos, BR-13565905 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 448, n. 1, p. 119-134, MAR 21 2015.
• Citações Web of Science: 2

Resumo

We studied a sample of stars associated with the Sh 2-296 nebula, part of the reflection nebulae complex in the region of Canis Major R1 (CMa R1). Our sample corresponds to optical counterparts of X-ray sources detected from observations with the XMM-Newton satellite, which revealed dozens of possible low-mass young stars not yet known in this region. A sample of 58 young star candidates were selected based on optical spectral features, mainly H alpha and lithium lines, observed with multiobjects spectroscopy performed by the Gemini South telescope. Among the candidates, we find 41 confirmed T Tauri and 15 very likely young stars. Based on the H alpha emission, the T Tauri stars were distinguished between classical (17 per cent) and weak-lined (83 per cent), but no significant difference was found in the age and mass distribution of these two classes. The characterization of the sample was complemented by near- and mid-infrared data, providing an estimate of ages and masses from the comparison with pre-main-sequence evolutionary models. While half of the young stars have an age of 1-2 Myr or less, only a small fraction (similar to 25 per cent) shows evidence of IR excess revealing the presence of circumstellar discs. This low fraction is quite rare compared to most young star-forming regions, suggesting that some external factor has accelerated the disc dissipation. (AU)

• Processo FAPESP: 10/50930-6 - Evolução química e populações estelares galácticas e extragalácticas, por espectroscopia e imageamento
• Beneficiário: Beatriz Leonor Silveira Barbuy
• Linha de fomento: Auxílio à Pesquisa - Temático