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IAUC 4751: 1987A; 1989 DA

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                                                  Circular No. 4751
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 or GREEN@CFA.BITNET    MARSDEN or GREEN@CFAPS2.SPAN


SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD
     R. M. Catchpole and P. A. Whitelock, South African Astronomical
Observatory, telex:  "Photometric observations made at SAAO by many
people indicate that since day 400 the bolometric flux curve can be
divided into three segments with the following e-folding times (t_e)
in days:  Days 400-520, t_e(U-M) = 86.4 +/- 0.5, t_e(U-L) = 84.5 +/-
0.4; Days 520-620, 62.7 +/- 0.3, 58.1 +/- 0.2; Days 620-730, 69.3 +/-
1.1, 71.8 +/- 1.2.  The flux on Day 730 is 17 percent of the decay
energy of 0.078 solar masses of 56Co.  If a flux of 7 x 10E37 erg/s is
subtracted from the bolometric data, then the U-M decline rate remains
constant from Day 520 to Day 730 with t_e = 61.0 +/- 0.2 days.  This
flux of 7 x 10E37 erg/s may represent the contribution from a pulsar.
Alternative explanations include a light echo, a contribution from
radioactive decay products other than 56Co (e.g., 57Co) or changes in
the proportion of 56Co flux emitted in the U-M range.  In addition to
these general trends, there is also evidence for short-term variations
as reported on IAUC 4725."


1989 DA
     Improved orbital elements from MPC 14360:

     T = 1989 Feb.  3.844 ET          Peri. = 138.656
     e = 0.54064                      Node  = 349.114   1950.0
     q = 0.98663 AU                   Incl. =   6.414
       a =  2.14784 AU     n = 0.313114     P =   3.15 years

     1989 ET      R.A. (1950) Decl.     Delta      r       V
     Mar.  7    10 19.33    +18 06.8    0.072    1.062    14.7
           8    10 26.83    +15 15.1
           9    10 33.48    +12 38.7    0.080    1.071    14.8
          10    10 39.40    +10 16.5
          11    10 44.69    + 8 07.6    0.089    1.081    15.0
          12    10 49.46    + 6 10.9
          13    10 53.76    + 4 25.1    0.098    1.091    15.2
          14    10 57.66    + 2 49.2
          15    11 01.22    + 1 22.3    0.108    1.101    15.4
          16    11 04.47    + 0 03.3
          17    11 07.46    - 1 08.6    0.119    1.112    15.6


1989 March 6                   (4751)             Daniel W. E. Green

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