COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 467

                             Konkoly Observatory
                             Budapest
                             1970 September 30


               REMARK ABOUT WZ Sge


      WZ Sge is a binary star whose primary is a white
dwarf with a mass of 0.59 M_sun. The period is 81.5 minutes
and the mass ratio is 0.05 (ses Krzeminski and Kraft 1964).
If we suppose that the secondary component is also a white
dwarf (see Paczynski 1967) and that it fills up its Roche
lobe then we can find the mass of the secondary. We can also
find the rate of mass transfer and the rate of period change
caused by gravitational waves. Computation were made using
Salpeter's (1961) equation of state (zero temperature
approximation), and with condition that all the mass lost
by the secondary is transferred to the primary. The results
are given below as a function of hydrogen content of the
secondary.


        X       M_2/Msun        dM_2/dt  (g/sec)          dP/dt
       0.0      4.34 x 10^-3    -5.90 x 10^12           2.00 x 10^-15
       0.3      1.03 x 10^-2    -3.52 x 10^13           5.79
       0.5      1.57            -8.35                   9.52
       0.7      2.24            -1.73 x 10^14           1.42 x 10^-14
       1.0      3.51            -4.40                   2.38
                   
Here X denotes hydrogen content of the secondary.
      A more detailed treatment of this problem will be
given in Acta Astronomica.


Krzeminski, W., and Kraft, R.P. 1964 Ap. J., 140, 921 [BIBCODE 1964ApJ...140..921K ]
Paczynski, B., 1967 Acta Astron. 17, 287 [BIBCODE 1967AcA....17..287P ]
Salpeter, E.E., 1961 Ap.J., 134, 669 [BIBCODE 1961ApJ...134..669S ]


Krakow, May 1970
                         H. BRANCEWICZ

                      Astronomical Observatory
                      Jagellonian University