COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 890

                               Konkoly Observatory
                               Budapest
                               1974 May 18

    NOTES ON THE Be-STAR HR 1508 AND THE ECLIPSING
           BINARIES AA CETI AND BT ERI


The following observations have been obtained with the Copenhagen
50cm telescope and a four-channel ubvy-photometer at  Cerro La
Silla, Chile.

                HR 1508  (= KZP  6131).
This star was found to be variable from observations made on
six nights in November 1973, when it was used together with HR 1545
as a comparison star for RZ Eri.

   HJD                   V^*       b-y
42000.79-.83            5.800     +.013
  001.74-.80            5.765     +.023
  002.67-.82            5.794     +.024
  003.75                5.780     +.017
  004.67                5.760     +.023
  005.76                5.792     +.015
^* derived from differences to HR 1545 with  V=6.261 for this star.
Afterwards it was found that the star is included in the Second
Catalogue of Suspected Variables Stars (1965) as No. 6131, with  a
range in V from 5.9 to 5.99. It is classified as B5ne. The brightness
difference between the new observations and the values V=5.92
and B-V=-.10 given in the Bright Star Catalogue seems to be 
significant only in the V-band and absent in B.

                      AA CETI
A secondary minimum was observed on Feb. 14, 1972. The lightcurve
shows a constant phase of about 50 minutes duration (0.07p).
From the b-lightcurve the following time of mid-eclipse was derived:

Min II:               HJD 41330.6166
                              +/- 10 m.e.(estimated)
which is in good agreement with the ephemeris given by  Bloomer,
O - C = 0.0017d (1972).
A diaphragm of 30 seconds of arc was used, so that the light of
the secondary component (m_V=7.7, distance 8.5") was included in the
measurements.


Reference:

Bloomer, R.H., 1972: IBVS No. 745.



                           BT ERI

   A minimum was observed on Nov. 5, 1973 giving the following time
as the mean for all four colors:

              Min I: HJD 41991.60389
                            +/-   10 m.e.
Combined with the photographic times of minima given by Deurinck
and Goossens (IBVS No. 792, 1973), this leads to an improved period
of 2.112269 +/- .000010 days.
   On the previous night a few observations were obtained at phase
0.55p and 0.58p without any indication of an eclipse. Assuming these
observations to represent maximum light, the amplitudes are .92, .92,
.90 and .89 in u,v,b and y resp. Transforming y to V we obtain V=9.56
in maximum and V=10.45 in Min I. The duration of the primary minimum
was observed to be longer than 0.08p.



Cerro La Silla,
May 4, 1974.



                        B. GRONBECH
                   Copenhagen University Observatory
                   and European Southern Observatory.