COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      Number 1015

                                 Konkoly Observatory
                                 Budapest
                                 1975 July 2



          OBSERVATIONS OF THE PERIOD OF Y Leo




  The eclipsing variable Y Leo was observed photographically by
the writers in Bouzareah Observatory (Algiers) with the normal 
astrograph (D=340 mm; F=344 cm), using ORWO ZU - 1 plates.
  Twenty observations were obtained during three nights, from
which a normal minimum has been determined: JD hel 2492519d4370+-0.0003d.
A study of minimum moments obtained by various observers in the 
interval JD 2418 050-2442540 suggests a sinusoidal variation of the
period of Y Leo with P_1 = 12900 P ~~ 57.25 years, on which irregular
(abrupt) variations were superposed.
  The new light elements of Y Leo were obtained:
Min Hel= JD 2433689d4726+1.6860807d E+0.0270d sin 0.032258deg (E+7950).
  If the presence of a third body in the system were the cause of
the sinusoidal variation of the period, its mass should be M_3~~0.65M_Sun,
assuming M_1=1.6M_Sun; M_2=0.55M_Sun; i=85.2deg, according to the data of 
Svechnikov's catalogue (Publ.Ural.Univ. 88, Ser.Astr. N5, 1969).





Astronomical Observatory
Bouzareah - Algiers


                       A. GHEZLOUN
                       M.A. SVECHNIKOV