The first note on the possible light variability of HV Ursae Majoris (= HD 103576 = HIP 58157, , , , mas, pc) was published by Penston (1973) who gave an `uncertain' mark to the range of V-magnitude ("var? V=8.60-8.83"). The periodic nature of the light variation was discovered by the Hipparcos satellite (ESA 1997) and the star was classified as an RRc variable. There is a note in ESA (1997) about the possibility of a double period but no firm conclusion was drawn. ESA (1997) gives a spectral type A3, while Slettebak & Stock (1959) published A7.
We started a long-term observational project of Strömgren photometry and spectroscopy of the newly discovered bright Hipparcos variables. The first results have already appeared in Kiss et al. (1999a,b). Since the period, spectral type and light curve do not exclude the possibility of wrong classification, accurate determination of the fundamental physical parameters is highly desirable.
The main aim of this paper is to present the first UBV and uvby photometry for HV UMa. Also, our radial velocity measurements are the first time-resolved spectroscopic observations of this star to date. The paper is organised as follows: the observations are described in Sect. 2, Sect. 3 deals with data analysis and the obtained physical parameters, while a discussion of the results is given in Sect. 4. A final list of conclusions is presented in Sect. 5.
© European Southern Observatory (ESO) 2000
Online publication: April 10, 2000