COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 2162

                                   Konkoly Observatory
                                   Budapest
                                   1982 June 15

                                   HU ISSN 0374-0676




IMPORTANCE OF UBV OBSERVATIONS OF AU Mon DURING JANUARY-FEBRUARY
                            1983




  The mathematical analysis of the photometric peculiarities of AU Mon
(Lorenzi, 1980a,b) has allowed to separate the variable light curve into two
overlapped periodic phenomena, one of the variations due to eclipses, the other
to intrinsic variation, with the ephemerides:


M(E) : 2442801.3752 + 11.1130371 E
                 51           68            (1)


Max(E) : 2443105 + 411 E
               4                            (2).



  In order to describe univocally the previous brightness behaviour of
AU Mon, the light surface device (Lorenzi, 1980b) has been introduced.
  At present we would emphasize the importance of future UBV observations
of AU Mon during January-February 1983. In fact the ephemeris (2) involves
the occuring of a brightness minimum of the intrinsic variation just in
the middle of this period, which, besides, is the best epoch for observing
AU Mon. A photometric snapshot of the eclipsing variation relating to such
period should allow a geometrical solution of the system to compare both
with the average one already computed (Lorenzi, 1982) and with another
solution referring to the maximum of the intrinsic variation.



L. LORENZI

Casella postale 24
10025 Pino Torinese (To)
Italy

References:

Lorenzi, L.: 1980a, Astron. Astrophys. Suppl. Ser. 40, 271 [BIBCODE 1980A&AS...40..271L ]
Lorenzi, L.: 1980b, Astron. Astrophys. 85, 342 [BIBCODE 1980A&A....85..342L ]
Lorenzi, L.: 1982, Acta Astron. (in press) [BIBCODE 1982AcA....32..431L ]