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IAUC 3751: LMC X-3: A Poss. BLACK HOLE; Occns BY COMETS; Occn OF BD +38 542 BY (375); Corrs

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IAUC number

                                                  Circular No. 3751
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM     Telephone 617-864-5758

     A. P. Cowley, D. Crampton and J. B. Hutchings, Department of
Astronomy, University of Michigan, write: "Observations at Cerro
Tololo Interamerican Observatory show that the radial velocity of
the optical counterpart of LMC X-3 (~ B3 absorption spectrum)
varies with an orbital period of 1.7049 days.  The large semiamplitude
of the velocity curve (K = 235 +/- 11 km/s) gives a mass function
of 2.3, implying a massive (~ 6 M-sun) unseen companion.   Maximum
radial velocity occurred at JD 2445283.56.  Fragmentary information
on the magnitude suggests there may be at least one minimum
per orbit, but further photometry on the period is needed."

     M. Combes, J. Lecacheux, B. Sicardy, Y. Zeau, T. Encrenaz and
L. Vapillon, Observatoire de Meudon; and D. Malaise, Institut
d'Astrophysique, Liege, report observations with a counting photometer
(range 600-900 nm, 1-m reflector) at Pic du Midi on Sept. 30
and Oct. 1 of occultations of stars by comets 1980b (Bowell) and
1981f (P/Churyumov-Gerasimenko).  There was significant absorption,
to 0.5 or more, of the light of a mag 15 star within 10 000-
20 000 km of the nucleus of comet 1980b.  On the other hand, the
absorption of the light of a mag 14 star was less than 0.25 at
2000 km from the nucleus of comet 1981f.

     P. Maley, Houston, TX, communicates the following visual
observations of this Nov. 15 event by T. Williams (0.15-m reflector),
A. Kelly (0.2-m reflector) and himself (0.13-m refractor).
Personal equations have been applied for the last two observers.
Uncertainties are < 0.5 s.  No secondary events were recorded.

  Immersion     Emersion       Long.         Lat.       Observer
    h  m  s      h  m  s      deg '  "      deg '  "
  11 11 00.0   11 11 16.7   -94 44 55.5   +29 50 13.0   Williams
  11 11 01.3   11 11 17.1   -95 13 06.1   +29 28 51.5   Kelly
  11 11 01.3   11 11 14.9   -94 23 56.9   +29 49 34.5   Maley

IAUC 3663, Comet Hartley (1982b), line 1.  For  Marc  read  Malc.
IAUC 3749, Supernovae, line 7.  For  A. T.  read  J.

1982 December 3                (3751)              Brian G. Marsden

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