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Chemically peculiar stars as seen with 2MASS

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HERDIN Andreas PAUNZEN Ernst NETOPIL Martin

Rok publikování 2016
Druh Článek v odborném periodiku
Časopis / Zdroj ASTRONOMY & ASTROPHYSICS
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
Doi http://dx.doi.org/10.1051/0004-6361/201527390
Obor Astronomie a nebeská mechanika, astrofyzika
Klíčová slova stars: chemically peculiar; stars: early-type; techniques: photometric
Popis Context. The chemically peculiar (CP) stars of the upper main sequence are well suited for investigating the impact of magnetic fields and diffusion on the surface layers of slowly rotating stars. They can even be traced in the Magellanic Clouds and are important to the understandine of the stellar formation and evolution. Aims. A systematic investigation of the near-infrared (NIR), 2MASS. JHK(s), photometry for the group of CP stars has never been performed. Nowadays, there is a great deal of data available in the NIR that reach very large distances. It is therefore very important for CP stars to be unambiguously detected in the NIR region and for these detections to be used to derive astrophysical parameters (age and mass) by applying isochrone fitting. Furthermore, we investigated whether the CP stars behave in a different way to normal-type stars in the various photometric diagrams. Methods. For our analysis, we carefully compiled a sample of CP and apparently normal (non-peculiar) type stars. Only stars for which high-quality (i.e. with low error levels), astrometric, and photometric data are available were chosen. In total, 639 normal and 622 CP stars were selected and further analysed. All stars were dereddened and calibrated in terms of the effective temperature and absolute magnitude (luminosity). Finally, isochrone fitting was applied. Results. No differences in the astrophysical parameters derived from 2MASS and Iohnson UBV photometry were found. Furthermore, no statistical significant deviations from the normal type stars within several colotu--colour and colour magnitude diagrams were discovered. Therefore, it is not possible to detect new CP stars with the help of the photometric 2MASS colours only. A new effective temperature calibration, valid for all CP stars, using the (V - K-S)(0) colour was derived.
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