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IAUC 5075: V1521 Cyg; 1990 MB; 1990c

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                                                  Circular No. 5075
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


V1521 CYGNI
     E. B. Waltman, R. L. Fiedler, and K. J. Johnston, Naval
Research Laboratory; and F. Ghigo, National Radio Astronomy Observatory,
report that the source Cygnus X-3 (V1521 Cyg) is flaring at
radio frequencies.  The NRL-Green Bank Interferometer Monitoring
Program observed intensities of 8 Jy at 8.3 GHz and 7 Jy at 2.2
GHz on Aug. 15.0 UT.


1990 MB
     With reference to IAUC 5067, H. Kinoshita, National Astronomical
Observatory, Tokyo, writes that a 10 000-year integration by
M. Yoshikawa using the orbital elements given there "clearly shows
this minor planet is a stable Martian Trojan"; and K. A. Innanen,
York University, Toronto, notes in the abstract of a very recent
paper by S. Mikkola and himself that "contrary to intuition, there
is clear empirical evidence for the stability of motion around the
L4 and L5 points of all the terrestrial planets over a timeframe
of several million years".
     E. Bowell, Lowell Observatory, provides the improved orbital
elements below from observations that now cover a 40-day arc.
These new figures indeed suggest greater stability than do the set
on IAUC 5067, and a computation by B. G. Marsden, Center for
Astrophysics, shows the object's distance from Mars to change only
from 1.5-1.8 AU around 1850 to 1.3-1.6 AU around 2400.

                    Epoch = 1990 Nov.  5.0 ET
     T = 1990 Oct. 29.1464 ET         Peri. =  95.2727
     e = 0.064820                     Node  = 244.4595  1950.0
     q = 1.424769 AU                  Incl. =  20.2806
       a =  1.523524 AU    n = 0.5241192    P =   1.881 years


COMET LEVY (1990c)
     Total visual magnitude estimates (cf. IAUC 5070):  Aug. 7.05 UT,
5.4 (B. H. Granslo, Fjellhamar, Norway, 7x35 binoculars); 9.14, 5.5
(A. Pereira, Linda-a-Velha, Portugal, 9x34 binoculars); 11.20, 4.5
(C. S. Morris, Pine Mountain Club, CA, naked eye); 13.71, 4.6 (M.
Ohkuma, Tokyo, Japan, 11x80 binoculars); 15.17, 4.3 (G. Kronk, Troy,
IL, naked eye).


1990 August 15                 (5075)             Daniel W. E. Green

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