COMMISSION 27 OF THE I.A.U.
              INFORMATION BULLETIN ON VARIABLE STARS
                           Number 1412

                                                     Konkoly Observatory
                                                     Budapest
                                                     1978 April 19


      CONFIRMATION OF THE delta Sct-TYPE VARIABILITY OF Theta2 TAURI

Recently Horan (1977) announced that Theta2 Tau (= HR 1412) is a delta Sct
variable with an amplitude of 0m.03 and a period of 0.07 days, on the basis
of a three-hour V run using Theta1 Tau for comparison. Here we present the
results of a six-hour UBV run, using 80 Tau as comparison star. Observations
were obtained with the same single channel photometer, attached to the
40 cm Cassegrain telescope on Tortugas Mountain. A dry ice cooled 1P21
multiplier was used, the signal was fed to a VFC and a counter. For each
colour three 10s integrations were averaged into a single observation, and
a sequence CVVC was taken for the derivation of one brightness difference.
The instrumental magnitude differences are given in the accompanying table
and figure. The variability discovered by Horan was found to exist at all
wavelengths (Delta u = 0m.03:, Delta b = 0m.02, Delta v = 0m.02). The period
was determined to P = 0.080 +- 0.002 days.


Table 1. Magnitude differences (variable - comparison)

J.D.hel.                              J.D.hel.
(2 443 483+) DeltaU DeltaB   DeltaV (2 443 483+) DeltaU DeltaB  DeltaV

.6746      -2.217   -2.288   -2.157   .8138   -2.252   -2.314   -2.183
.6906      -2.274   -2.310   -2.172   .8253   -2.224   -2.296   -2.174
.7048      -2.275   -2.316   -2.185   .8357   -2.225   -2.294   -2.166
.7197      -2.255   -2.314   -2.176   .8461   -2.227   -2.301   -2.169
.7308      -2.241   -2.311   -2.174   .8565   -2.232   -2.303   -2.176
.7427      -2.215   -2.298   -2.161   .8670   -2.245   -2.313   -2.180
.7538      -2.221   -2.294   -2.164   .8774   -2.244   -2.306   -2.179
.7701      -2.257   -2.306   -2.173   .8871   -2.252   -2.311   -2.180
.7808      -2.251   -2.311   -2.184   .8969   -2.245   -2.298   -2.168
.8017      -2.257   -2.309   -2.184   .9086   -2.236   -2.293   -2.165


                            [FIGURE 1]

Figure 1. Brightness differences of Theta^2 Tau relative to 80 Tau on
1977 December 6 (UT)


                                 H. W. DUERBECK

                                 Observatorium Hoher List
                                 der Universitats-Sternwarte Bonn
                                 5568 Daun/Eifel, F.R.G.

                                 and

                                 Department of Astronomy
                                 New Mexico State University
                                 Las Cruces, NM 88001, U.S.A.



Reference :

Horan, S. 1977, Inf. Bull. Var. Stars 1232