COMMISSION 27 OF THE I. A. U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                            Number 3592

                                                       Konkoly Observatory
                                                       Budapest
                                                       19 April 1991

                                                       HU ISSN 0374- 0676



                   HD 127759: A NEW DELTA SCUTI VARIABLE

  Photometric photometry of HR 5437 (SAO 016411), HD 127759 (SAO 016405),
HD 127411 (SAO 016394) and HD 127822 (SAO 016408) was obtained between 1991
March 22 and April 8. The spectral types of these stars are in the range of
A0 to F5. The 60 cm reflector at Xinglong Station of Beijing Astronomical
Observatory China together with a photometer in DC mode (Shi et al., 1987)
was used. Observations were made through a standard Johnson V filter.
  On the night of 1991 April 4, we observed HR 5437, HD 127759, HD 127411
and HD 127822 for six hours. The differential analysis shows that the light
curves of HD 127759 relative to both HD 127822 and HD 127411 tend to show
the same variation. The period of variation is about 1.6 with an amplitude
of 0.06m, These features can be seen from Figures 1 and 2. The light curve
of HD 127759 relative to HR 5437 also supports this result. HD 127411 and
HD 127822 seem to be stable within an error of = 0.009m, its differential
curve shows a random variation (see Figure 3).


                              [FIGURE 1]

 Fig. 1. The light curve of HD 127759 relative to HD 127822 (April 4)

                              [FIGURE 2]

 Fig. 2. The light curve of HD 127759 relative to HD 127411 (April 4)

                              [FIGURE 3]

 Fig. 3. The differential curve of HD 127411 - HD 127822 (April 4)

                              [FIGURE 4]

 Fig. 4. The light curve of HD 127759 relative to HD 127822 (April 7)

                              [FIGURE 5]

 Fig. 5. The light curve of HD 127759 relative to HD 127411 (April 7)

                              [FIGURE 6]

 Fig. 6. The differential curve of HD 127411 - HD 127822 (April 7)


   The above results were confirmed by the observations made on the night
of April 7. During six hours of observations, the differential light curves,
no matter which of HD 127411 or HD 127822 was used as comparison, both show
the same periodic variation which cover three cycles as presented in Figures
4 and 5. The period and amplitude are the same as that of April 4 basically.
Figure 6 shows the magnitude differences between HD 127882 and HD 127411
which is constant within 0.015m and gives = 0.0074m during this night. So
the observations of April 4 and 7 both show the same result, and the choice
of either HD 127822 or HD 127411 as comparison does not affect the basic
feature of the light variation in HD 127759.
   The spectral type of HD 127759 is F0, in accordance with the spectral
range of delta Scuti variables. Its period and amplitude are in agreement
with that of known delta Scuti variables. So we tend to classify it to be a
delta Scuti type variable with a visual magnitude of 8.41m.


               LI ZHIPING *1, JIANG SHIYANG *1, LIU YIANGYIN *1, CAO MING *2

*1 Beijing Astronomical Observatory, Academia Sinica, Beijing, China, 100080
*2 Shaanxi Astronomical Observatory, Academia Sinica, Lintong, China, 710600



Reference:

Shi, C.M., Du, B.T. et al.: 1987, Acta Astrophysica, 7, 230. [BIBCODE 1987AcApS...7..230S ]