2008/06/30 by A. Roman-Lopes, Alexandre Roman–Lopes, Z. Abraham +3 · 1 citation
Chemistry · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Infrared #Molecular Spectroscopy and Structure #Nebula #Physics #Planetary nebula #Spectral line #Spectrograph #Star formation #Stars #Stellar classification #Supergiant #Young stellar object #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.14319.x
This is the version that will be published by the Montly Notices of the Royal Astronomical Society
arxiv created 2008/12/03 · openalex publication_date 2009/02/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 μm, respectively. One of them, I16177IRS1, 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.