COMMISSION 27 OF THE I.A.U.
                INFORMATION BULLETIN ON VARIABLE STARS
                             Number 2922

                                                        Konkoly Observatory
                                                        Budapest
                                                        4 August 1986

                                                        HU ISSN 0374 - 0676


                  1986 J,K LIGHT CURVES OF II Peg

IP Peg (HD 224085, SAO 091578) was observed during 6 nights from 19 to 26 June
1986, with the 1.5m Infrared Flux Collector at the Observatorio de Izana
(Tenerife), using the IR single-channel photometer with an InSb detector
cooled with liquid-nitrogen and the broad band filters J and K.
   In order to check errors in the photometry we observed also the closest
comparison star (SAO 091577).
   The observed magnitudes were corrected for extinction by observation of
standard stars (Koorneeff 1983) and reduced to Johnson's system. The
dispersion in the comparison star was 0.01 magnitudes.
   Table I gives the Julian heliocentric date, the J magnitude and the J-K
colour, for each observation.


                              Table I

                       JHD       J        J-K
                     2446000+

                     601.707    5.32     0.76
                     602.707    5.39     0.80
                     604.708    5.52     0.79
                     605.662    5.49     0.71
                     606.728    5.39     0.77
                     607.703    5.32     0.75


                          [FIGURE 1]

   In the Figure we have plotted J and K magnitudes against phase calculated
using the ephemerides of Rucinsky (1977):

            JD = 2443033.10 + 6.724183E

   It is interesting to note the clear delay between the minima in both
filters. The minimum in J occurred near phase 0.15 while it was at about 0.30
in K.
   A more detailed study of these light curves complemented by data in other
filters is in preparation.


                     C. LAZARO and M. T. AREVALO
                 Instituto de Astrofisica de Canarias
                   38071 La Laguna, Tenerife, Spain.



References:

Koorneeff, J.: 1983, Astr. Ap. Suppl. Ser. 51, 489. [BIBCODE 1983A&AS...51..489K ]
Rucinsky, S.M.: 1977, Publ. Astron. Soc. Pac., 89, 280. [BIBCODE 1977PASP...89..280R ]