COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                    NUMBER 295

                                   Konkoly Observatory
                                   Budapest
                                   1968 September 2


AUTOCORRELATIVE AND SPECTRAL ANALYSIS OF THE LIGHT VARIATION OF AE Aqr.


Autocorrelative and spectral analyses of 2390 unpublished observations of AE
Aqr in U region was carried out as described in [1]. The observations were
made by M.F. Walker in 1958-1957 on the Mount-Wilson Observatory 60-inch
reflector with Corning 9863 filter. They are kept in the Royal Astronomical
Society library in London. On request from the Main Astronomical Observatory
of the Ukrainian Academy of Sciences, Dr.E.W. Maddison kindly sent a copy of
the observations to Kiev.


                          [FIGURE 1]

A unit of correlative interval is taken equal to 0.^d001. The maximum
correlative interval (Tau) is equal to 100 unit. The received autocorrelative
(a) and spectral (b) functions are shown by points on the figure 1. The solid
curve is calculated by the formula:

r_tau=0,75 e^(-tau^d/0,042) cos(2pi/0,2) tau^d

It describes the principal run of r_tau with tau and corresponds to a
stochastic process:

xi(t)=A cos((2pi/0,2)t^d + b)

where A and b are stochastic values. Moreover oscillations with maxima near
the correlative intervals 0.^d01, 0.^d03 and 0.^d05 are seen on the correlative
function. The existence of oscillations of such periods is confirmed by the
spectral density curve. Besides small maxima near the enumerated periods and
a possible maximum near P=0.^d016 there is an increase of S(P) with P related
to the main component of the process with P=0.^d2. As seen from the value
r_tau at tau=0, the dispersion of this component is three times greater than
the sum, of dispersions of the rest observations. Periods near 0.^d701 and
0.^d4 discovered by A.S. Joy [3] and M.F. Walker [4] from radial velocities
are not seen from the examined observations of AE Aqr. If such oscillations
exist, their dispersions are not greater than those for the enumerate short
period oscillations.

Therefore, basing on the examined row of observations, the main part of the
light variation process of AE Aqr in U region may be mathematically modelled by
a harmonic oscillation with P=0.^d2 and stochastic amplitude and phase.

It is a plessure to acknowledge my sincere thanks to Dr.E.W. Maddison for the
copy of observations and the troubles of sending it to us and to A. Jemets for
calculations on an electronic computer.


August, 1968
                                      F.J. LUKAZKAJA
                              Main Astronomical Observatory
                       of the Ukrainian Academy of Sciences, Kiev

LITERATURE

1. F.J. Lukazkaja. Astrophysica, 2, 345, 1966.
2. M.F. Walker. IAU(27) RAS-2, November, 1966.
3. A.H. Joy. ApJ, 120, 377, 1954.
4. M.F. Walker, Sky and Telescope, 29, 23, 1965.