COMMISSION 27 OF THE I. A. U.
            INFORMATION BULLETIN ON VARIABLE STARS
                         Number 3420

                                               Konkoly Observatory
                                               Budapest
                                               12 January 1990

                                               HU ISSN 0374 - 0676


          THE NATURE OF THE VARIABILITY OF HD 177559

  While engaged in a photometric monitoring program of Be stars, it was soon noted by
the author that one of the comparison stars used (HD 177559) was in itself a variable star
(Halbedel, 1986). A literature search soon revealed that variability for the star had been previously 
suggested. HD 177559 is listed as BV 888 (Strohmeier, 1967) with a range in the
photographic of 0.4 magnitudes. Also, it is NSV 11722 in the CATALOGUE OF SUSPECTED
VARIABLE STARS (Kholopov, 1982) with a smaller range of 0.2 V magnitudes, information
probably derived from Kilkenny & Hill (1975). The star's variability in radial velocity has long
been known. Neubauer (1943) found a range of 200 km/sec from six plates and remarked that
the lines were wide and shallow. Spectral types for the star range from B2/3 V(n) (Houk &
Smith-Moore, 1988) to B5 I (Abt & Biggs, 1972) to B6 Vn (Hill et al., 1975). No emission
has ever been noted in the spectrum.
  Consequently, HD 177559 was determined to be sufficiently interesting to observe on its
own merit. 382 BV observations on 21 nights over HJD range 2446313 - 7839 were made
with the Corralitos Observatory 0.6-m telescope and single channel photon-counting photometer
which utilizes an EMI 9924A photomultiplier tube. The comparison stars used were HD
177290 (V = 8.33; B-V = +.18) and HD 177423 (V = 7.977; B-V = -.009). The average standard 
errors in V for the standard stars were 0.020 and 0.019 in B-V, not unreasonable for
observations of southerly stars generally observed by necessity at high air masses.
  It soon became evident that HD 177559 was an eclipsing variable of reasonably short
period. Figure 1 shows that both minima are of approximately the same depth and that there is
little or no color change throughout the orbital cycle. The preliminary elements found are:
        Min = HJD 2447794.66258 + 0.7148 * E
  Both stars are probably nearly identical in spectral type and luminosity. The orbit is
likely to be circular since there is no displacement of the minima in phase. However, there are
evidently non-sphericity or reflection effects since the minimum placed arbitrarily at phase 0.5
is definitely asymmetric. Unfortunately, few observations of the maxima were obtained. Therefore, 
the range in variability was tentatively assigned to be 0.6 V magnitudes for both minima.
  The short period and relative brightness of the star as well as its large ranges in optical
and radial velocity variations would seem to suggest that HD 177559 would be a profitable
system to study both photometrically and spectroscopically in the future.


                                [FIGURE 1]

               FIGURE 1: V and B-V Light Curves for HD 177559.



                E.M. HALBEDEL

                Corralitos Observatory
                P.O. Box 16314
                Las Cruces, NM
                U.S.A. 88004

REFERENCES

Abt, H.A. & Biggs, E.S. (1972), BIBLIOGRAPHY OF STELLAR RADIAL VELOCITIES, 
   (A.U.R.A.: Tucson) [BIBCODE 1972bsrv.book.....A ]
Halbedel, E.M. (1986), Inf. Bull. Var. Stars, No. 2919.
Hill, P.W., Kilkenny, D., & van Breda, I.G. (1974), Mon. Not. Royal Astr. Soc., 168,
   451. [BIBCODE 1974MNRAS.168..451H ]
Houk, N. & Smith-Moore, M. (1988), MICHIGAN SPECTRAL CATALOGUE, Vol. 4,
   (Univ. of Mich.: Ann Arbor). [BIBCODE 1988mcts.book.....H ]
Kholopov, P.N. (1982), NEW CATALOGUE OF SUSPECTED VARIABLE STARS,
   (Nauka: Moscow). [BIBCODE 1982ncss.book.....K ]
Kilkenny, D. & Hill, P.W. (1975), Mon. Not. Royal Astr. Soc., 172, 649. [BIBCODE 1975MNRAS.172..649K ]
Neubauer, F.J. (1943), Astrophys. J., 97, 300. [BIBCODE 1943ApJ....97..300N ]
Strohmeier, W. (1967), Inf. Bull. Var. Stars, No. 178.