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IAUC 4941: 1989c1; LMC X-2

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IAUC number 

                                                  Circular No. 4941
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


COMET AUSTIN (1989c1)
     Improved parabolic orbital elements from MPC 15672:

     T = 1990 Apr. 9.847 ET           Peri. =  61.504
                                      Node  =  75.409   1950.0
     q = 0.34963 AU                   Incl. =  58.911

     1990 ET      R.A. (1950) Decl.     Delta      r       m1
     Jan. 19     0 32.50    -44 00.6    2.043    1.773     8.5
          24     0 35.26    -41 22.6
          29     0 38.69    -38 37.8    1.960    1.607     8.0
     Feb.  3     0 42.71    -35 45.8
           8     0 47.26    -32 45.8    1.869    1.434     7.4
          13     0 52.28    -29 36.6
          18     0 57.72    -26 17.1    1.769    1.253     6.7
          23     1 03.54    -22 45.6
          28     1 09.68    -19 00.2    1.661    1.064     5.9
     Mar.  5     1 16.09    -14 58.3
          10     1 22.67    -10 37.0    1.542    0.867     4.8
          15     1 29.28    - 5 52.4
          20     1 35.69    - 0 39.7    1.409    0.662     3.5

     Total visual magnitude estimates: 1989 Dec. 30.56 UT, 10.3 (A.
Pearce, Scarborough, Western Australia, 0.20-m reflector); 1990 Jan.
1.07, 9.5: (A. Hale, Las Cruces, NM, 0.41-m reflector); 3.57, 10.0 (Pearce).


LMC X-2
     P. Schmidtke and A. P. Cowley, Arizona State University; and D.
Crampton and J. B. Hutchings, Dominion Astrophysical Observatory,
report: "Photometry of LMC X-2 from Cerro Tololo Interamerican
Observatory indicates that this LMXB has a long orbital period,
probably 12.539 days.  During nine consecutive nights (1989 Nov.
28-Dec. 6) the optical light brightened slowly from V = 18.2 to 18.0
and then declined to V = 18.4.  During 1988 Dec. 7-13 V declined from
18.1 to a minimum of 18.9 on Dec. 10.86 UT and then returned to V =
18.1 a few nights later.  Irregular flickering of several tenths of a
magnitude on timescales of a few hours is superposed on this longer
variation.  If our ephemeris is correct, LMC X-2 should again be at
minimum light near 1990 Jan. 16 and 28, Feb. 10 and 23, etc., and
further observations are encouraged."


1990 January 12                (4941)              Brian G. Marsden

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