COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3240

                                                         Konkoly Observatory
                                                         Budapest
                                                         20 September 1988

                                                         HU ISSN 0374 - 0676


                   THE VARIABLE STAR 42 PERSEI

Following the suggestion of Batten (1987), we have made photometric and
spectroscopic observations of the photometrically variable single-lined
spectroscopic binary 42 Persei = HR1177 = HD23848 = V467 Persei.
   Differential V-filter photometry was carried out on ten nights between
January and March, 1988, using the 0.5-m telescope at the Devon Astronomical
Observatory. HR1164 was used as the comparison star.
   A total of nine spectroscopic observations were made during five nights
in February, 1988, using the Reticon detector and the Cassegrain spectrograph
(reciprocal dispersion = 1.5 nm.mm-1) on the 1.85-m telescope at the Dominion
Astrophysical Observatory, Victoria. Radial velocities have been determined
using a cross-correlation technique. (Additional spectroscopic observations
were made in August, 1988, but those data have not been reduced as yet).
   Analyses of both our new photometric and spectroscopic data sets support
Batten's conclusion that the 1.765346d spectroscopic orbital period found by
Morbey and Brosterhus (1974) is correct and that it does fit the light, as
well as the radial velocity, variations.
   The raw -- not transformed to the standard UBV system -- v magnitude
differences in the sense HR1164 - HR1177 are plotted in Figure 1. The Delta v
values have been phased from periastron passage, T = JD2437640.03, using
p = 1.765346d as given by Morbey and Brosterhus, and have been averaged over
phase intervals of 0.05 P. Minimum light occurs between phases 0.5 and 0.6
which, within the uncertainties of this limited data set, coincides with
primary conjunction in the spectroscopic orbit. The large scatter in the
plotted data is due, in large measure, to the observations having been made
at large zenith distances near the end of the observing season.
   Our new spectroscopic data suggest the need for a very small correction
of +0d.000005 to the orbital period, but no other significant changes to the
previously published orbital elements.

                           [FIGURE 1]

 Figure 1.  Visual magnitude differences between HR1164 and 42 Per.


   Our results are consistent with Batten's conclusion that 42 Per is
probably an ellipsoidal variable. During the coming observing season we
intend to obtain complete, multi-colour light curves in collaboration with R.
Wasson, Sunset Hills Observatory, California, and with W.S. Barksdale,
Florida. A more detailed analysis and discussion of the combined
spectroscopy and photometry will be published elsewhere.


             BRIAN E. MARTIN and DOUGLAS P. HUBE

                   Department of Physics
                   University of Alberta
                     Edmonton, Alberta
                      Canada T6G 2J1



References:

Batten, A.H., 1987, Info. Bull. Var. Stars, No. 3111.
Morbey, C.L. and Brosterhus, E.B., 1974, Pub. Astr. Soc. Pacific, 86, 455. [BIBCODE 1974PASP...86..455M ]