Resumo

ŠIMON, Vojtěch. Long-term optical activity of the hard X-Ray flaring star DG CVN. Rev. mex. astron. astrofis [online]. 2017, vol.53, n.1, pp.59-66. ISSN 0185-1101.

DG CVn is a young late-type star which displayed an X-ray and optical superflare in 2014. This paper presents an analysis of the long-term activity of this object in the optical band. I used the photographic data from DASCH (Digital Access to a Sky Century @ Harvard). These measurements from the years 1895-1989 cover the blue spectral region. CCD V -band ASAS data were used for several UV Cettype stars to place the activity of DG CVn in the context of flaring stars. I show that three large brightenings (flares) of DG CVn by more than 1 mag were detected on the DASCH plates. The character of the long-term activity (regarding the histogram of brightness) of DG CVn is compatible with those of flaring stars UV Cet and V371 Ori. The flares brighter than ∼ 0.4 mag represent less than 1 percent of the observed data in all three objects.

Palavras-chave : methods: observational; radiation mechanisms: general; stars: flare; stars: individual (DG CVn); stars: late-type; X-rays: stars.

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