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IAUC 5813: 6 Cep; Cyg X-1; N Aql 1993

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                                                  Circular No. 5813
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


6 CEPHEI
     L. Szabados and M. Kun, Konkoly Observatory, Budapest,
communicate: "The well-known Be star 6 Cep = HR 8171 = HD 203467 has
been remarkably stable from a photometric point of view for years,
the yearly mean values being as follows:  1989, V = 5.20, B-V =
-0.06, U-B = -0.58; 1990, 5.22, -0.05, -0.56; 1991, 5.23, -0.06,
-0.54; 1992, 5.22, -0.05, -0.54.  In 1993, however, a definite
brightening is observed, which may indicate the commencement of a
new activity phase.  The recently obtained data are:  1993 May
29.86 UT, V = 5.10, B-V = -0.01, U-B = -0.61; June 9.84, 5.08,
+0.01, -0.62; 9.94, 5.09, -0.01, -0.62.  These magnitudes have been
measured at Konkoly using 7 Cep = HR 8227 as the comparison star,
constancy of which was regularly checked against HR 8133.  Spectroscopic
observations are recommended in order to study the mass
motion in the stellar atmosphere while this episode lasts."


CYGNUS X-1
     B. A. Harmon, G. J. Fishman, and C. A. Wilson, Marshall Space
Flight Center, NASA; W. S. Paciesas, University of Alabama, Huntsville;
and J. C. Ling and W. A. Wheaton, Jet Propulsion Laboratory,
California Institute of Technology, report for the Compton
Observatory/BATSE Team:  "Hard x-ray emission from the black-hole
candidate Cygnus X-1, measured using the Earth occultation technique,
has decreased gradually from a flux level of 0.12 to about 0.08
photon cmE-2 sE-1 (45- to 140-keV band) from early May to about May
23.  As of June 8, the flux remained at 0.07-0.09 photon cmE-2 sE-1.
The two flux levels correspond roughly to the gamma2 (higher flux)
and gamma1 (lower flux) states observed in 1979-1980 by HEAO-3
(Ling et al. 1987, Ap.J. 321, L117).  These observations indicate
the possibility of a gamma2 to gamma1 transition which has not been
seen previously."


NOVA AQUILAE 1993
     Further CCD photometry from H. Mikuz, Ljubljana, Slovenia (cf.
IAUC 5807): May 31.986 UT, V = 8.54 +/- 0.02, B-V = +0.50 +/- 0.04;
June 2.063, V = 8.76 +/- 0.02; 6.020, V = 9.20 +/- 0.04 (strong
moonlight).


1993 June 11                   (5813)            Daniel W. E. Green

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