Photometric Strömgren-Hβ Quantification for O and B Stars of Luminosity Class V

Author(s): Nadia Kaltcheva, Valeri Golev, Ernst Paunzen
Abstract: In any photometric system, the relationship between the spectral type and the intrinsic colors is fundamental for the photometric stellar classification and for a reliable derivation of stellar parameters. Such relationships are being constantly verified and improved based on larger and better samples. The capability of the Strömgren-Hβ photometry to provide reddening-free quantities allows the classification of reddened stars over the entire spectral sequence. However, a detailed consistent tabulation of the uvbyβ quantities for the O-B9 part of the main sequence is currently warranted. We combine spectral types and photometry from the literature to provide a new empirical tabulation of the intrinsic color b - y, color differences c₁, m₁, [c₁] and [m₁] and the Hβ index for main-sequence (luminosity class V) stars of spectral types O4.5 through B9.5 in terms of spectral sub-types. Our survey is based on more than 1400 stars. We use the established c₁ versus b - y intrinsic line and the accepted reddening slopes to obtain dereddened quantities and then calculate their median values as a function of the spectral sub-type. The classification ability of the system in this spectral range is reliable and the photometric quantities are not affected by the stellar rotation.
Organisation(s): Department of Astrophysics
External organisation(s): University of Wisconsin, Oshkosh, Sofia University "St. Kliment Ohridski", Masaryk University
Journal: Publications of the Astronomical Society of the Pacific
Volume: 129
No. of pages: 10
ISSN: 0004-6280
DOI: https://doi.org/10.1088/1538-3873/aa8cbd
Publication date: 11-2017
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
Portal url: https://ucrisportal.univie.ac.at/en/publications/f315e1df-f93e-44a7-bd31-2a454b1d986b

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