Circular No. 3689 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 PROBABLE SUPERNOVA IN NGC 4490 Paul Wild, Astronomical Institute, Berne University, reports his discovery of a probable supernova 35" east and 20" south of the nucleus of NGC 4490 (= Arp 269; R.A. = 12h28m.2, Decl. = +41o54', equinox 1950.0). The photovisual magnitude on Apr. 15 UT was ~ 16. AM HERCULIS J. A. Mattei, American Association of Variable Star Observers, Communicates that this irregular variable has begun another decline, according to the following visual magnitude estimates by E. Mayer, Barberton, OH: Mar. 29.25 UT, 13.5; Apr. 19.26, [15.0. NOVA AQUILAE 1982 D. C. B. Whittet, M. F. Bode and D. Kilkenny, South African Astronomical Observatory, telex the following simultaneous optical and infrared magnitudes of this object, obtained on April 14.14 UT: U= 13.25, B = 13.85, V = 13.53, R = 12.7, I = 12.2, J = 9.34, H = 7.10, K = 5.33, L = 3.44. KR AURIGAE A. Shafter, University of California at Los Angeles, writes: "Spectroscopic observations of the unusual variable star KR Aur (recently reported to be fading in brightness by Wisniewski and Ferguson, IAUC 3674; and Popov, IBVS 2095) have revealed the object to be a close binary system with a 3.907-hr orbital period. The orbital period has been derived from sinusoidal velocity variations (semiamplitude ~ 50 km/s) of the H-alpha emission line. Based on the character of the spectrum, which shows broad (~ 750 km/s fwhm) H and He emission, and the short orbital period, it appears that KR Aur is a cataclysmic variable." PERIODIC COMET SCHWASSMANN-WACHMANN 1 The following further total visual magnitude estimates and coma diameters have been reported: Apr. 16.13 UT, 13.0, 1'.0 (C. S. Morris, Harvard, MA, 0.25-m reflector); 18.26, 12.5, 0'.7 (A. Hale, Costa Mesa, CA, 0.20-m reflector); 19.14, 12.6, 0'.8 (Morris); 20.08, 12.4, 1'.2 (Morris). 1982 April 20 (3689) Daniel W. E. Green
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