Circular No. 3931 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 617-495-7244/7440/7444 SUPERNOVA IN NGC 3169 E. Waagen, AAVSO, reports that R. Evans, Maclean, N.S.W., discovered a supernova in NGC 3169 (R.A. = 10h11m7, Decl. = +3deg43', equinox 1950.0) on Mar. 29.5. A confirmatory observation by T. Cragg at the Anglo-Australian Observatory gave mag 15.0 (using the AAVSO X Leo sequence) and offset from the nucleus 50" west, 40" north. Shortly afterward, a cablegram received from E. P. Aksenov, Sternberg Astronomical Institute, gave a report from Yu. V. Terebizh, Sternberg Crimean Station, that Nataliya Metlova discovered the object on Mar. 26.82 UT at mpg = 14.5; the offset from the galaxy's nucleus was given as 56" west, 13" north. A telex received subsequently from Y. Kozai, Tokyo Astronomical Observatory, noted that the supernova was also discovered independently on Mar. 26 by Kiyomi Okazaki, Kahoku-machi, Yamagata, at mv = 15.0 and located 10" due west of the nucleus. epsilon AURIGAE J. Kemp, G. Henson and D. Kraus, Physics Department, University of Oregon, report: "Optical photometry on 200 nights during 1982 July-1984 March shows, for the interval of totality from second to third contacts, (a) an overall slow drop in the normalized Q Stokes parameter (which correlates approximately with the orbit- plane position angle of 95) by 0.5 (+/- 0.1) percent; and (b) additional variations in both Stokes parameters with a kind of quasiperiod on the order of 100 days, the peak-to-peak amplitude varying by as much as 0.5 percent. There is no appreciable color dependence among U, B and V. Considering lightcurve data assembled by Hopkins and Stencel (see N Aurigae Newsletters), we judge that the photometric counterparts of these strong polarization features do not exceed 0.05 mag. We attempt to explain the effects by limb and envelope scattering in the F-supergiant primary, modulated by the eclipsing dark disk. Feature (a) would mean that the disk is slightly tilted to the left or right with respect to the projection of the orbit on the plane of the sky. Feature (b) could be due to equatorial (non-radial) pulsation of varying amplitude in the primary: if so, a detailed explanation requires the primary's spin axis also to be tilted left or right by ~ 20 deg. The geometry is clearly not symmetrical." 1984 March 30 (3931) Brian G. Marsden
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