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IAUC 4969: 1990F; MWC 560; 1990 DA

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                                                  Circular No. 4969
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

     C. Pollas, Observatoire de la Cote d'Azur, reports his
discovery on Schmidt plates taken by A. Maury of a possible
supernova located at R.A. = 13h36m46s.48, Decl. = +32 24'32".9
(equinox 1950.0), which is 5".6 west and 1".4 south of the nucleus
of an anonymous face-on spiral galaxy; end figures of a nearby star
(mpg 18.5):  41s.55, 35".1.  Magnitude estimates of the SN
candidate:  Jan. 23.2 UT, B > 22.3; Feb. 24.1, V about 18.7;
25.0, B about 19.2.  There is a very faint, diffuse, blue
condensation at the location of the SN.

MWC 560
     A. G. Michalitsianos, S. P. Maran, and R. Oliversen,
Laboratory for Astronomy and Solar Physics, Goddard Space Flight
Center, write:  "Observations of the peculiar M4e giant star
MWC 560 (IAUC 4955) on Feb. 4 with the International Ultraviolet
Explorer show that since 1984 March, when the star was previously
examined with IUE, the ultraviolet flux (120-320 nm) has increased
by about 50 percent and the visible light (400-700 nm) countrate
registered by the IUE Fine Error Sensor has approximately doubled.
The 120- to 320-nm continuum is marked by prominent Fe II
absorption lines (many of which have strengthened since 1984) and
by absorption from other low-excitation metals, consistent with
the presence of an optically-thick shell around a mass-accreting
companion star.  Strong emission in the Si II 126.5-nm multiplet
(4), O I 130.1 nm, and C II 133.5 nm is found in the Feb. 4 spectra,
suggesting that the shell may be thinning optically.  A visual
estimate obtained recently by B. Bopp indicates that MWC 560 is
at magnitude 11.5."

1990 DA
     R. P. Binzel, Department of Earth, Atmospheric, and Planetary
Sciences, Massachusetts Institute of Technology, reports the
following photometric results obtained with the McDonald Observatory
0.91-m telescope on Feb. 23 and 24:  rotation period 5.82 +/- 0.05
hr; lightcurve amplitude 0.36 +/- 0.02 mag; B-V = +0.87 +/- 0.03.
Mean V magnitudes (i.e., mean between lightcurve extrema): Feb.
23.18 UT, 14.64 +/- 0.02; Feb. 24.15, 14.71 +/- 0.02.  These data
are suggestive of a type-S minor planet.

1990 February 26               (4969)             Daniel W. E. Green

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