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IAUC 5899: 1993J; P/ENCKE

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                                                  Circular No. 5899
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


SUPERNOVA 1993J IN NGC 3031
     H.-U. Zimmermann, B. Aschenbach, G. Hasinger, W. Pietsch, P.
Predehl, and J. Trumper, Max-Planck-Institut fur Extraterrestrische
Physik; W. Lewin and E. Magnier, Massachusetts Institute of Technology;
J. van Paradijs, University of Amsterdam; G. Fabbiano, Center
for Astrophysics; L. Lubin, Princeton University; and R. Petre,
Goddard Space Flight Center, report:  "On Nov. 1 and 2, SN 1993J
was again observed by the x-ray satellite ROSAT.  Since the last
observation in May, the PSPC count rate in the energy band 0.1-2.4
keV has decreased from 0.053 +/- 0.0025 to 0.035 +/- 0.0014 count/s.
The energy spectrum has become significantly softer (with kT about
0.5 keV for a thermal bremsstrahlung model, compared to > 7 keV for
the May measurements).  The low-energy x-ray absorption corresponds
to a neutral hydrogen column density of about 3 x 10E21 cmE-2,
which is about a factor of 6 higher than in the May observation.
The change in the absorbing column density and the low temperature
seem to indicate that part of the wind material, lost by the
progenitor star and highly ionized by the radiation from the initial
shock, has started to recombine."


PERIODIC COMET ENCKE
     Ephemeris from orbital elements on MPC 18256:

1993/94     R. A. (2000) Decl.   Delta     r    Elong. Phase    m1
Nov. 29    22 40.37   + 7 28.4   0.953   1.457   97.4   42.2   12.1
Dec.  4    22 36.29   + 6 36.3   0.956   1.388   91.2   45.2   11.7
      9    22 33.33   + 5 50.8   0.956   1.316   85.4   48.2   11.3
     14    22 31.34   + 5 11.5   0.954   1.242   79.7   51.2   10.9
     19    22 30.18   + 4 37.6   0.947   1.166   74.2   54.3   10.5
     24    22 29.64   + 4 07.8   0.936   1.087   69.0   57.6   10.1
     29    22 29.48   + 3 40.0   0.918   1.006   63.8   61.3    9.6
Jan.  3    22 29.41   + 3 11.6   0.893   0.921   58.6   65.6    9.2
      8    22 28.98   + 2 38.5   0.861   0.834   53.2   70.9    8.8
     13    22 27.57   + 1 53.9   0.821   0.744   47.6   77.7    8.3
     18    22 24.12   + 0 46.6   0.774   0.651   41.4   86.9    7.9
     23    22 16.84   - 1 03.1   0.721   0.558   33.9   99.9    7.4
     28    22 02.96   - 4 07.0   0.669   0.467   24.5  119.2    7.1


1993 November 30               (5899)            Daniel W. E. Green

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