GEMINI near-infrared spectroscopic observations of young massive stars embedded in molecular clouds

Autor(es)

Roman-Lopes, A. ^[1] ; Abraham, Z. ^[2] ; Ortiz, R. ^[3] ; Rodriguez-Ardila, A. ^[4]

Afiliação do(s) autor(es)

^[1] Univ La Serena, Dept Phys, La Serena - Chile

^[2] Univ Sao Paulo, IAG, Dept Astron, BR-05508900 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, BR-03828000 Sao Paulo - Brazil

^[4] Lab Nacl Astrofis, BR-37504364 Itajuba - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 394, n. 1, p. 467-478, Mar. 2009.
• Área do conhecimento: Ciências Exatas e da Terra - Astronomia
• Citações Web of Science: 15
• Assunto(s): Estrelas Regiões HII (astronomia)

Resumo

K-band spectra of young stellar candidates in four Southern hemisphere clusters have been obtained with the Gemini Near-Infrared Spectrograph in Gemini South. The clusters are associated with IRAS sources that have colours characteristic of ultracompact H ii regions. Spectral types were obtained by comparison of the observed spectra with those of a near-infrared (NIR) library; the results include the spectral classification of nine massive stars and seven objects confirmed as background late-type stars. Two of the studied sources have K-band spectra compatible with those characteristic of very hot stars, as inferred from the presence of C iv, N iii and N v emission lines at 2.078, 2.116 and 2.100 um, respectively. One of them, I16177_IRS1, has a K-band spectrum similar to that of Cyg OB2 7, an O3If* supergiant star. The nebular K-band spectrum of the associated Ultra-Compact (UC) H ii region shows the s-process [Kr iii] and [Se iv] high excitation emission lines, previously identified only in planetary nebula. One young stellar object was found in each cluster, associated with either the main IRAS source or a nearby resolved Midecourse Space eXperiment (MSX) component, confirming the results obtained from previous NIR photometric surveys. The distances to the stars were derived from their spectral types and previously determined JHK magnitudes; they agree well with the values obtained from the kinematic method, except in the case of IRAS 15408-5356 , for which the spectroscopic distance is about a factor of 2 smaller than the kinematic value. (AU)

• Processo FAPESP: 04/10375-2 - Estudo de regioes de formacao estelar a partir de fotometria e espectroscopia no infravermelho proximo e de observacoes de linhas moleculares em frequencias de radio.
• Beneficiário: Alexandre Roman Lopes
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado