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IAUC 5115: SATURN; 1990 SM

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IAUC number 

                                                  Circular No. 5115
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


SATURN
     The following visual central meridian timings of the new white
spot, together with those on IAUC 5105, 5109, and 5111, imply that
a rotation period, P about 10h17m +/- 5 min, and that P is not
lengthening appreciably as suggested on IAUC 5111:  Oct. 3.239 UT
(A. Hale, Las Cruces, NM); 4.093 (S. J. O'Meara, Cambridge, MA; spot
had length 24 deg and was located at longitude 337 deg in System I);
4.096 (Hale).  More recent observations by members of the Agrupacion
Astronomica de Tenerife indicate that by Oct. 10 the original Wilber
white spot had so lengthened in longitude as to cover most of the
disk, thereby making central transit timings nearly impossible.  M.
Kidger reports the appearance of several new white spots, including
a small, very brilliant, new white spot immersed in the Wilber spot,
which transited the central meridian on Oct. 10.889.  A second,
smallish, extremely brilliant white spot, also superimposed on the
Wilber spot, was detected simultaneously and independently by O.
Gonzalez and V. Gonzalez with the 0.51-m Mons reflector at Tenerife,
and by P. Rodriguez and B. Garcia with the 0.40-m Vacuum Newton
Telescope, with meridian transit timings averaging at Oct. 10.91;
this is close to the longitude of the original outburst of the
Wilber spot.  A third, larger, and somewhat less brilliant ellipse
was seen within the Wilber spot, close to its trailing edge; this
spot occupied the full width of the equatorial zone and transited
the meridian at Oct. 10.93.


1990 SM
     Astrometric observations of this object are urgently needed.
Ephemeris extension to IAUC 5099 from orbital elements on MPC 17025:

     1990 ET      R.A. (1950) Decl.     Delta      r       V
     Oct. 16    22 30.58    -31 03.3    0.581    1.403    17.4
          26    22 48.31    -26 50.3
     Nov.  5    23 02.58    -23 32.1    0.947    1.633    18.7
          15    23 15.48    -20 44.1
          25    23 27.88    -18 14.3    1.348    1.842    19.7
     Dec.  5    23 40.15    -15 56.5
          15    23 52.44    -13 47.4    1.769    2.032    20.4


1990 October 11                (5115)             Daniel W. E. Green

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