EARLY RESULTS FROM THE GALACTIC O-STAR SPECTROSCOPIC SURVEY: C III EMISSION LINES IN Of SPECTRA
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- Instituto de Astrofisica de AndalucIa-CSIC, Glorieta de la Astronomia s/n, 18008 Granada (Spain)
- Las Campanas Observatory, Observatories of the Carnegie Institution of Washington, Casilla 601, La Serena (Chile)
- Departamento de Fisica, Universidad de La Serena, Cisternas 1200 Norte, La Serena (Chile)
On the basis of an extensive new spectroscopic survey of Galactic O stars, we introduce the Ofc category, which consists of normal spectra with C III {lambda}{lambda}4647-4650-4652 emission lines of comparable intensity to those of the Of defining lines N III {lambda}{lambda}4634-4640-4642. The former feature is strongly peaked to spectral type O5, at all luminosity classes, but preferentially in some associations or clusters and not others. The relationships of this phenomenon to the selective C III {lambda}5696 emission throughout the normal Of domain, and to the peculiar, variable Of?p category, for which strong C III {lambda}{lambda}4647-4650-4652 emission is a defining characteristic, are discussed. Magnetic fields have recently been detected on two members of the latter category. We also present two new extreme Of?p stars, NGC 1624-2 and CPD -28 deg. 2561, bringing the number known in the Galaxy to five. Modeling of the behavior of these spectral features can be expected to better define the physical parameters of both normal and peculiar objects, as well as the atomic physics involved.
- OSTI ID:
- 21305085
- Journal Information:
- Astrophysical Journal Letters, Vol. 711, Issue 2; Other Information: DOI: 10.1088/2041-8205/711/2/L143; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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