COMMISSION 27 OF THE I. A. U
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 258

                                    Konkoly Observatory
                                    Budapest
                                    1968 February 29


   THE MASSES OF BM CAS, X CYG, RT AUR, RR LYR


Prosecuting the program of study on giant variables stars (1), we present the
curves sigma=sigma(M)_Te,R (T_e,R of the static model) obtained applying our
computational method to the following stars:  BM Cas (Fig. 1), X Cyg (Fig.
2), RT Aur (Fig. 3) and RR Lyr (Fig. 4).

                        [FIGURE 1]
                        [FIGURE 2]
                        [FIGURE 3]
                        [FIGURE 4]


From the curves it follows that if the stars oscillate on the fundamental mode
the deduced masses are:

          Te        R         M/M_sun
BM Cas   4400   1.56x10^13    13.5
X Cyg    5000   4.77x10^12     2.8
RT Aur   6000   9.6x10^11      0.45
RR Lyr   8000   3.75x10^11     0.65

The masses of BM Cas and RR Lyr are very close to those deduced by Thiessen (2)
and R.F. Christy (3).


A. MASANI, A. MARTINI
Astronomical Observatory of Milan

E. ALBINO
University of Genoa
C.N.R. Centro di calcolo

(1) Inf. Bull. on Variable Stars No 251 [BIBCODE 1968IBVS..251....2M ]
(2) Zeit. f. Astr. 39, 65, 1956 [BIBCODE 1956ZA.....39...65T ]
(3) Bamberg 77 (1965) [BIBCODE 1965VeBam..27...77C ]