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IAUC 3931: SN IN NGC 3169; epsilon Aur

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                                                  Circular No. 3931
Central Bureau for Astronomical Telegrams
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

     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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