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IAUC 4383: 1987n; GX 339-4

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IAUC number 

                                                  Circular No. 4383
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM    Telephone 617-495-7244/7440/7444


PERIODIC COMET HARRINGTON (1987n)
     T. Gehrels and J. V. Scotti report their recovery of this comet
with the 0.91-m SPACEWATCH telescope at Kitt Peak, as shown below.
On May 3, a 15" coma was visible.  The correction to the elements
on MPC 10522 (ephemeris on MPC 11753) is Delta(T) about -0.05 day.

      1987 UT            R. A.  (1950)   Decl.         m1
      May   1.44971    19 32 56.34    -15 58 20.7     20.0
            1.46970    19 32 57.41    -15 58 17.3
            3.43966    19 34 56.31    -15 54 44.5
            3.46595    19 34 57.82    -15 54 40.9     20.0
            3.47062    19 34 58.07    -15 54 41.3
            3.47549    19 34 58.42    -15 54 41.3


GX 339-4
     R. A. Remillard and J. E. McClintock, Massachusetts Institute
of Technology, write:  "The optical counterpart of GX 339-4 (cf.
IAUC 3613) has faded to mag 20, and observers are cautioned that
the image is a close double.  We observed GX 339-4 with the 0.9-m
telescope (and the Cassegrain-focus CCD instrument) at Cerro Tololo
Interamerican Observatory using B, V, and I filters (1".0 seeing).
The southeast component of the faint double appears to coincide
with the position of GX 339-4 in its bright state, and the photometric
magnitudes of this component are variable.  We deconvolved
the double image with the software 'daophot', using point spread
functions determined from nearby field stars.  The components are
separated by 1".13 +/- 0".03 along p.a. about 125 deg.  The northwest
component appears constant, with the following photometric magnitudes
(errors given parenthetically in units of 0.01): V = 20.32 (5), B-V
= +1.47 (10), V-I = +1.84 (8).  The results for the southeast
component (GX 339-4) are as follows: Apr. 23.34 UT, V = 20.18 (6), B-V
= +1.29 (12), V-I = +1.59 (8); 28.50, 20.72 (12), +1.07 (16), +1.84
(17).  The optically faint state of this low-mass x-ray binary may
exhibit the orbital period, which has not been detected during
extensive observations in its bright state (V = 15.5-16.6)"


EX HYDRI
     F. Bateson, RASNZ, relays a report from A. F. Jones, Nelson,
New Zealand, that EX Hyi is in outburst at mv = 9.6 on May 4.82 UT.

1987 May 5                     (4383)            Daniel W. E. Green

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