COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                    Number 2168

                                  Konkoly Observatory
                                  Budapest
                                  1982 June 23

                                  HU ISSN 0374-0676




           1981 PHOTOMETRY OF UX ARIETIS




  As part of our long-term project of photometry of RS CVn stars, we observed
the non-eclipsing system UX Ari (= HD 21242) in fall-winter 1981. All 
observations were made with UNM's 61-cm telescope at Capilla Peak Observatory. 
The photon-counting photometer uses a cooled (-20dC) EMR 641A phototube. The
comparison star was 62 Ari (V = +5.54, G5). Integration times were chosen so
that the statistical error in each observation was +-0.01 mag. or better.
   Figures 1-4 show the magnitude differences [comparison-source) in the UBVR
instrumental bands. The phases were calculated from HJD=2440133.75 + 6.43791 E
(Landis et al., 1978). The distortion wave in the light curve is clearly visible:
it peaks at about phase 0.59, and bottoms out at phase 0.97. The amplitude of
the wave (peak to peak) in the instrumental magnitude system is: 0.15 mag at U,
0.17 mag at B, 0.21 at V, and 0.22 at R, with the system being reddest at the
distortion wave minimum.
   The phase and amplitude of the distortion wave in UX Ari has undergone
erratic behavior in the past 10 years (see Guinan et al., 1981, and the 
references cited there). In particular the phase of the minimum of the distortion
wave moved toward decreasing orbital phase in 1972-77; but between early and
late 1980, it moved toward increasing phase. For: 1981.0, Guinan et al. (1981)
cite a phase 0.97 for minimum, the same as our late 1981 result. So the 
distortion wave's phase has remained steady for a year and perhaps will move
retrograde again.

                           [FIGURE 1]
                           [FIGURE 2]
                           [FIGURE 3]
                           [FIGURE 4]

   From 1977 to 1981, the amplitude of the wave at V has varied from 0.04
to 0.17, with Guinan et al. (1981) giving 0.16 for 1981.0. Our results indicate
that the amplitude has increased since then.



         M. ZEILIK, R. ELSTON, G. HENSON, and P. SMITH

                  Capilla Peak Observatory

                The University of New Mexico

                   Albuquerque, NM 87131

                           U.S.A.





References:
                          
Guinan, E.F., McCook, G.P., Fragola, J.L., O'Donnell, W.C., Weisenbergen,
    A.G., 1981, Pub.Astr.Soc.Pac., 93, 495. [BIBCODE 1981PASP...93..495G ]
Landis, H.J., Lovell, L.P., Hall, D.S., Henry, G.W., Renner, T.R., 1978,
    A.J., 83, 176. [BIBCODE 1978AJ.....83..176L ]