COMMISSION 27 OF THE I.A.U.
         INFORMATION BULLETIN ON VARIABLE STARS
                      NUMBER 138

                                          Konkoly Observatory
                                          Budapest
                                          9 June 1966

	PHOTOELECTRIC OBSERVATIONS OF THE NEW DELTA
		SCUTI VARIABLE HD 107904

	HD 107904 (F0) belonging to the Hyades moving group was
suggested by O. J. Eggen to be a delta Scuti-variable. From 22 spectra
taken with the 36" Yapp reflector D. H. P. Jones and C. M. Haslam (The
Observatory 86, 34, 1966) derived a radial velocity curve of about
30 km/sec amplitude and a period of 0.1707d -typical for a delta Scuti-
variable.
	A first series of photoelectric b, v observations with the 24"
reflector of the Lippert Astrograph (1966 May) covering a whole period
show the respective light variation (figure). The comparison star used
was BD +43deg2221 of spectral type F2, for which star preliminary 
measurements give V = 7.098m and B-V = 0.369m in the B, V system.
	The ordinates in the figure give the magnitude differences
Delta b = b^0_var-b^0_comp and Delta v = v^0_var-v^0_com in the instrumental 
system. The color B-V refers to the B, V system. As it was an extraordinary
photometric night the mean error of one observation turned out to be
about +/-0.002m.
	As yet photoelectric measurements have been made in 4
nights yielding the following results:

  Maximum	Delta m_b^max	ampl._b	     Delta m_v^max	ampl._v
243 9247.4423     -1.156m        0.150m        -1.127m           0.110m
    9259.5075:    -1.070         0.029         -1.067            0.019
    9262.4850     -1.100         0.065         -1.095            0.047
    9266.4129     -1.111         0.056         -1.096            0.044

			[FIGURE 1]

	It is known that variations in form and amplitude of the light
curve are quite usual for delta Scuti variables. Further observations are
urgently needed to get at the secondary period of these variations.

1966 May 29

						A. A. WACHMANN

					       Hamburg Bergedorf
						  Sternwarte