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arXiv · 1604.03842

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

Julia I. Arias·Nolan R. Walborn·Sergio Simon-Diaz·Rodolfo H. Barba·Jesus Maiz Apellaniz·Carolina Sabin-Sanjulian·Roberto C. Gamen·Nidia I. Morrell·Alfredo Sota·Amparo Marco·Ignacio Negueruela·Joao R. S. Leao·Artemio Herrero·Emilio J. Alfaro
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Abstract

On the basis of the Galactic O-Star Spectroscopic Survey (GOSSS), a detailed systematic investigation of the O Vz stars is presented. 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 4471, He II 4542, and He II 4686 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.

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Julia I. Arias, Nolan R. Walborn, Sergio Simon-Diaz, Rodolfo H. Barba, Jesus Maiz Apellaniz, Carolina Sabin-Sanjulian, Roberto C. Gamen, Nidia I. Morrell, Alfredo Sota, Amparo Marco, Ignacio Negueruela, Joao R. S. Leao, Artemio Herrero, Emilio J. Alfaro. 2016-04-13. Spectral classification and properties of the O Vz stars in the Galactic O-Star Spectroscopic Survey (GOSSS). https://doi.org/10.3847/0004-6256%2F152%2F2%2F31

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