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                                                  Circular No. 6069
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505

     M. K. Bird and O. Funke, University of Bonn; J. Neidhoefer,
Max-Planck-Institut fur Radioastronomie (MPIR), Bonn; and I. de
Pater, Department of Astronomy, University of California at
Berkeley, communicate:  "Radio observations of Jupiter were
performed at the Effelsberg Telescope before, during, and after the
July 16-22 impacts of comet 1993e.  Measurements of the four Stokes
parameters, yielding full-polarization characteristics of the
received signal, were recorded at three wavelengths:  2.8, 6, and
11 cm.  Generally consistent with similar radio observations
reported by Klein and Gulkis (IAUC 6042), Galopeau et al. (IAUC
6045), and Smits et al. (IAUC 6047), Jupiter's radio brightness was
found to increase monotonically during the impact week at all three
wavelengths.   The increase from July 16/17 to 21/22 was computed
at a representative point in the beaming curve when the system-III
central-meridian longitude was 290o (near the absolute peak).  The
absolute (relative) increases in total flux, referred to the
standard distance of 4.04 AU, were 1.2 +/- 0.1 Jy (18 percent) at
11 cm and 1.2 +/- 0.2 Jy (13 percent) at 6 cm.  A preliminary
analysis of the 11-cm observations shows an increase during the
impact week of about 2 percent in the relative linear polarization,
but no immediately-apparent changes in the polarization (position)
angle or circular polarization.   Post-impact observations taken on
Aug. 12/13 indicate a slight decrease (about 0.2 Jy) in total flux
with respect to the level recorded on July 21/22.  Jupiter's radio
brightness observed at the most recent Effelsberg observations on
Aug. 26/27 remained unchanged from the value on Aug. 12/13.  An
impact-induced relative increase in flux at 2.8 cm is apparent, but
further data processing is required before a quantitative statement
can be made."

     S. Benetti, L. Pasquini, and R. West, European Southern
Observatory (ESO); and V. de Lapparent, Institut d'Astrophysique de
Paris, report that a provisional inspection of a wavelength-
calibrated spectrum (391-880 nm) obtained on Sept. 2.07 UT with the
ESO 3.5-m New Technology Telescope (+ EMMI) of the possible MACHO
(cf. IAUC 6068) reveals no emission lines, a comparatively smooth
continuum, and the following main absorption features (relative
strengths indicated):  G-band (medium); H-beta (weak); Mg I b
triplet (strong); Fe I/Cr I complex (578.0-579.0 nm; medium); Na I
D doublet (very strong); H-alpha (medium).  The spectrum is
consistent with that of a normal K0-K2 III-V star.

1994 September 2               (6069)            Daniel W. E. Green

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