COMMISSION 27 OF THE I.A.U.
                INFORMATION BULLETIN ON VARIABLE STARS
                            Number 3260

                                                    Konkoly Observatory
                                                    Budapest
                                                    10 November 1988

                                                    HU ISSN 0374 - 0676


       THE OPTICAL BEHAVIOUR OF THE X-RAY SOURCE GX 304-1
                       DURING 1985-1988 *

GX 304-1 (4U 1258-61) is known to be a pulsating X-ray source
with a period of 272 s (McClintock et al., 1977). The optical
counterpart is a B main sequence star (Mason et. al., 1978) showing 
strong double-peaked H_alpha emission which systematically faded
out between 1978 and 1982 leaving H_alpha in absorption (Corbet et.
al., 1986). At the same time the system brightened in V from
~14.2 to ~13.7. Periodic X-ray flaring was found by Priedhorsky
and Terrell (1983) which is interpreted as reflecting the orbital
revolution of 132.5 d. There exist also off-states (Pietsch et.
al., 1986) where the X-ray flux is appreciably lower than in
quiescence. In the following some spectroscopic and photometric
observations are reported which might be useful for those interested 
in the long time behaviour of this system.
   The spectroscopy was performed in 1985-1988 using the Boller &
Chivens spectrograph attached to the ESO 1.5 resp. 3.6 m telescope 
with the IDS or a CCD as detector. Table 1 gives the
journal of observations. The spectra (Fig. 1) show no emission in
H_alpha thus indicating that the optical companion was still in its
inactive state.
   UBVRI photometry was obtained in Feb. 1985 using the ESO 50 cm
telescope equipped with the single-channel photometer. The 
results listed in Table 2 are in the same range as reported by
Corbet et al. (19861 for the year 1983. Continuous photometry in


                         [FIGURE 1]

 Figure 1  Spectra of GX 304-1. The spectrum of 1986 is of minor quality,
 arrows indicate pixel errors. The two spectra of 1985 are averaged.
 Most prominent features are identified.


                         Table I.

                  Spectroscopy of GX 304-1

Date                Tel.   Detec.   Disp.(A/mm)   Exp.(min)

1985 Feb. 26        1.5m    IDS       114           56
1985 Feb. 27        1.5m    IDS       114           68
1986 March 13       1.5m    IDS       114           40
1987 July 30        3.6m    CCD        59.5          2
1988 June 19        1.5m    CCD       172           20


                                Table II

                         Photometry of GX 304-1

    Date            V         B-V        U-B          V-R           V-I       n

1985 Feb. 24  13.67+-0.03  1.83+-0.09  0.66+-0.40   1.10+-0.03   2.33+-0.02  12
1985 Feb. 25  13.71+-0.02  1.81+-0.06  0.88+-0.34   1.11+-0.03   2.34+-0.02  11

Continuous photometry in integral light (duration 3 h, time resolution 4 s)
was additionally performed in 1985 March 2 and the data was searched for short
Continuous photometry in  No significant signal near the X-ray period of 272s could
be found.

* based on observations collected at the European Southern
   Observatory. La Silla/Chile


                    R. HAEFNER

               Universitats-Sternrnwarte
                    Scheinerstr. 1
                  D-8000 Munchen 80
                Fed. Rep. of Germany



References:

Corbet, R.H.D., Smale, A.P., Menzies, J.W., Branduardi-Raymont, G., Charles,
   P.A., Mason, K.O., Booth, L., Mon. Not. R. astr. Soc. 221., 961, 1986 [BIBCODE 1986MNRAS.221..961C ]
Mason, K.O., Murdin, P.G., Parkes, G.E., Visvanathan, N., Mon. Not. R. astr.
   Soc. 184, 45p, 1978 [BIBCODE 1978MNRAS.184P..45M ]
McClintock, J.E., Rappaport, S.A., Nugent, J.J., Li, F.K., Astrophys. J. 216,
   L15, 1977 [BIBCODE 1977ApJ...216L..15M ]
Pietsch, W., Collmar, W., Gottwald, M., Kahabka, P., Ogelman, H., Astron.
   Astrophys. 163, 93, 1986 [BIBCODE 1986A&A...163...93P ]
Priedhorsky, W.C., Terrell, J., Astrophys. J. 273, 709, 1983 [BIBCODE 1983ApJ...273..709P ]