Spectral classification and properties of the O VZ stars in the Galactic O-Star Spectroscopic Survey (GOSSS)

• Autores: Arias, Julia Inés; Walborn, Nolan Revere; Díaz, S. S.; Barbá, Rodolfo Héctor; Maíz Apellániz, Jesús; Sabín Sanjulián, C.; Gamen, Roberto Claudio; Morrell, Nidia Irene; Sota, Alfredo; Marco, A.; Negueruela, I.; Leão, J. R. S.; Herrero, A.; Alfaro, Emilio J.
• Año de publicación: 2016
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Astronómicas; stars: early-type; stars: fundamental parameters; surveys
• Institución: Universidad Nacional de La Plata

On the basis of the Galactic O Star Spectroscopic Survey (GOSSS), we present a detailed systematic investigation of the O Vz stars. The currently used spectral classification criteria are rediscussed, and the Vz phenomenon is recalibrated through the addition of a quantitative criterion based on the equivalent widths of the He i λ4471, He ii λ4542, and He ii λ4686 spectral lines. The GOSSS O Vz and O V populations resulting from the newly adopted spectral classification criteria are comparatively analyzed. The locations of the O Vz stars are probed, showing a concentration of the most extreme cases toward the youngest star-forming regions. The occurrence of the Vz spectral peculiarity in a solar-metallicity environment, as predicted by the fastwind code, is also investigated, confirming the importance of taking into account several processes for the correct interpretation of the phenomenon.
Instituto de Astrofísica de La Plata
Facultad de Ciencias Astronómicas y Geofísicas