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IAUC 5024: 1990K; CC Cnc; R CrB

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                                                  Circular No. 5024
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

     R. H. McNaught and E. M. Sadler, Siding Spring Observatory,
have reduced the following position of SN 1990K as a mean of six
frames taken on May 25 and 26 by K. Cooper, Sadler, J. Davies, and
R. Evans using the Thompson CCD and f/1 focal reducer on the Anglo-
Australian Telescope:  R.A. = 0h31m45s.371, Decl. = -28 04'18".58
(equinox 1950.0, +/- 0".3 in each coordinate); offset from the
nucleus is 18".4 west, 26".6 north.

     U. Munari, A. Bianchini, and R. Claudi, Padova and Asiago
Observatories, communicate:  "In the course of our spectroscopic
monitoring of dwarf novae with the 1.82-m telescope of the Asiago
Astrophysical Observatory, we discovered CC Cnc in outburst on
1990 Feb. 17 and declining on Feb. 18 and 19.  Twenty-four Boller
and Chivens (+ CCD) spectra in the region from H10 to H-beta at
0.2 nm/pixel resolution showed an A-type continuum distribution
with broad Balmer absorption lines.  A central emission peak was
visible in H-beta and H-gamma with average FWHM of 880 km/s.   At
some phases, a double-peaked emission profile was observed with a
separation of about 700 km/s.  He II (468.6 nm) was weakly in
emission. Fourier analysis of radial velocities of both absorption
and emission components of Balmer lines gives as the most probable
orbital period P = 2.26 hr.  However, the aliases at P = 2.51, 2.78,
and 3.14 hr also give satisfatory fits.  The semiamplitude is about
130 km/s for absorptions and 90 km/s for the emissions.  If
confirmed, P = 2.26 hr would place CC Cnc inside the cataclysmic
variable's period gap."

     E. Waagen, AAVSO, reports that this variable is undergoing
peculiar fluctuations in brightness.  Visual magnitude estimates
(cf. IAUC 4885):  1989 Nov. 3.80, 6.4 (A. Pereira, Cabo da Roca,
Portugal); 27.0, 6.2 (J. E. Bortle, Stormville, NY); Dec. 26.19,
6.1 (P. Schmeer, Bischmisheim, West Germany); 1990 Mar. 5.12, 6.3
(A. Boattini, Florence, Italy); 24.94, 6.2 (J. Shanklin, Cambridge,
England); May 20.23, 5.9 (C. Scovil, Wrightwood, CA); 25.39, 6.6
(Scovil); 26.25, 5.9 (Scovil, Big Bear, CA); 27.18, 5.6 (Bortle,
Big Bear, CA); 29.18, 5.7 (Scovil, Wrightwood, CA).

1990 May 29                    (5024)             Daniel W. E. Green

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