Astron. Astrophys. 350, 513-516 (1999)

1. Introduction

The most recent estimates for the variable star V 368 Cep are K2v, , (constant) and (Our Table 1: Bianchi et al. 1991; Chugainov et al. 1991, 1993; Bossi & La Franceschina 1995). EXOSAT imaging by Pravdo et al. (1985) revealed that V 368 Cep (HD220140) is the optical counterpart of the bright X-ray source H2311+77 detected with the HEAO1 satellite (Nugent et al. 1983). Subsequent IUE-, EUVE- and ROSAT-satellite detections include chromospheric, transition region and coronal emission at shorter wavelengths (Bianchi et al. 1991; Bowyer et al. 1994; Malina et al. 1994; Pye et al. 1995). The first evidence for magnetic activity, strong Caii H&K emission, was already detected by Joy & Wilson (1949). Indications of magnetic activity have been observed in 11 groups of late-type stars (Hall 1991). Earlier studies by Pravdo et al. (1985), Nations et al. (1990), Bianchi et al. (1991) and Chugainov et al. (1991, 1993) have implied that the RS CVn (Hall 1976), BY Draconis (Bopp & Fekel 1977) or naked T Tauri (Walter 1986) group definitions might be relevant for V 368 Cep. Regardless of uncertainties in spectral-type or luminosity class, several activity-rotation-relations (e.g. Strassmeier et al. 1990) would predict high level of magnetic activity in V 368 Cep, all available estimates exceeding those of a typical late-type star (see Gray 1982, 1989; Gray & Nagar 1985). Halliwell (1979) included this object among stars maybe within 25 pc, and later estimates ranged between 21 and 70 pc (Pravdo et al. 1985; Chugainov et al. 1991, 1993). The Hipparcos satellite confirmed the distance of 20 pc (ESA 1997).

Table 1. [1] Boss (1937), [2] Joy & Wilson (1949), [3] Wilson & Joy (1950), [4] Moore & Paddock (1950), [5] Wilson (1953), [6] Poretti et al. (1985), [7] Heckert et al. (1990), [8] Nations et al. (1990), [9] Bianchi et al. (1991), [10] Chugainov et al. (1991, 1993), [11] Mantegazza et al. (1992), [12] Bossi & La Franceschina (1995), [13] Fekel (1997)

© European Southern Observatory (ESO) 1999

Online publication: October 4, 1999
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