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IAUC 3318: LMC X-2; Cyg X-2; WZ Sge

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IAUC number 

                                                  Circular No. 3318
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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


LMC X-2
     M. Pakull and J.-P. Swings, European Southern Observatory and
Universite de Liege, report that a spectrogram (dispersion 170 A/mm)
of the proposed optical counterpart of LMC X-2 (IAUC 3313) was secured
with the 360-cm telescope and image-dissector scanner.  It reveals
the presence of He II 4686 A, H-alpha and probably C III-N III
4640-4650 A emission, leaving little doubt about its association
with the x-ray source.


CYGNUS X-2
     N. Marshall and M. G. Watson, X-Ray Astronomy Group, Leicester
University, report that analyses of the Ariel 5 ssi observations of
Cyg X-2 made between 1974 and 1976 reveal a significant modulation
at 9.84 days, consistent with both period and phase of the optical
observations reported by Crampton and Cowley (IAUC 3292).  The x-ray
minimum occurs near phase 0.5 according to their ephemeris, as
expected if the modulation is due to obscuration of the x-ray
source by matter near the optical star.  The full amplitude of the
modulation is 30 percent of the mean intensity (2-18 keV).


WZ SAGITTAE
     A. Kruszewski, Warsaw University Observatory, and W.
Krzeminski, Copernicus Astronomical Center, communicate: "E.
Bogusz and A. Udalski monitored the nova WZ Sge in B on the nights
Dec. 6-7, 7-8 and 8-9.  The nova continues to vary with amplitude
0.3 magnitude, and it faded to 9.2 in B.  Single broad maxima and
minima follow the pre-outburst ephemeris.  Secondary minima are absent.
     Further visual magnitude estimates: Dec. 12.97 UT, 9.6 (C. S.
Morris, Prospect Hill Observatory); 15.08, 9.6 (P. L. Collins,
Mount Hopkins Observatory); 18.01, 10.0 (D. Levy, Amherst View, Ontario);
21.99, 10.5 (J. E. Bortle, Brooks Observatory); 26.01, 10.5
(J. deYoung, Huntington, WV); 28.96, 10.8 (Bortle); 30.02, 10.9 (L.
Hyatt, Arlington, VA); 1979 Jan. 1.10, 12.6 (J. Morgan, Prescott,
AZ); 2.11, 12.7 (Morgan).


1979 January 3                 (3318)              Daniel W. E. Green

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