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IAUC 5881: CH Cyg; V1357 Cyg; R CrB

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                                                  Circular No. 5881
Central Bureau for Astronomical Telegrams
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

     J. P. Aufdenberg, K. D. Gordon, and B. W. Bopp, Ritter Observatory,
University of Toledo, write: "The symbiotic star CH Cyg has
shown an abrupt change in the emission profiles of H-alpha, He I
587.5-nm, and the Na I D-lines.  CCD echelle spectra (resolution
0.025 nm) obtained at Ritter Observatory between June 30 and Oct. 4
UT showed a single strong emission line at H-alpha, with essentially
constant profile.  On Oct. 8, the H-alpha line was markedly
different, with an additional emission component present at -163 km
sE-1.  On the same night, the FWHM of the He I 587.5-nm emission
line doubled, a P-Cyg absorption component of this line appeared at
-200 km sE-1, and P-Cyg structure in the Na I D-lines developed.
These sudden and unusual changes in spectral behavior have
persisted and intensified through Oct. 14."

     B. A. Harmon, G. J. Fishman, B. C. Rubin, and C. A. Wilson,
Marshall Space Flight Center, NASA; and W. S. Paciesas, University
of Alabama at Huntsville, report for the Compton Observatory BATSE
Team:  "Hard x-ray emission from the black-hole candidate V1357 Cyg
(Cygnus X-1), measured using the earth-occultation method, decreased
gradually in the band 45-140 keV from a flux level of 0.12
to about 0.05 photon cmE-2 sE-1 between early September and Oct.
10, and remained at a low flux level as of Oct. 17.  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).  The September-October light curve is
similar to that observed in May-June (IAUC 5813)."

     Further visual magnitude estimates (cf. IAUC 5864), provided
in part by the AAVSO:  Sept. 20.82 UT, 6.7 (G. Comello, Groningen,
The Netherlands); 27.78, 6.7 (G. Zajacz, Debrecen, Hungary); Oct.
1.08, 6.6 (D. York, Abiquiu, NM); 4.08, 7.0 (York); 8.20, 6.6 (C.
E. Spratt, Victoria, BC); 9.75, 7.5 (P. Schmeer, Bischmisheim,
Germany); 11.75, 7.3 (L. Szentasko, Budapest, Hungary); 16.81, 7.4
(A. Pereira, Cabo da Roca, Portugal); 19.80, 7.5 (Pereira).

1993 October 20                (5881)            Daniel W. E. Green

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