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IAUC 5978: FG Sge; N Cas 1993; 1994I; 3C 279

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                                                  Circular No. 5978
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


FG SAGITTAE
     E. F. Guinan and G. P. McCook, Villanova University, report:
"FG Sge, the peculiar, pulsating central star of the planetary
nebula He 1-5, is undergoing another large dimming event.  UBVRI
photoelectric photometry, carried out with the Four College
Consortium 0.8-m APT at Mt. Hopkins, shows a about 1.2-mag decrease
in its V-band brightness from Mar. 23 to Apr. 19 UT.  FG Sge had
undergone its first recorded sudden dimming and reddening episode
in Aug-Sept. 1992 (IAUC 5604, 5609, 5610, 5619, 5632) and since
then has been slowly recovering in brightness.  The behavior of FG
Sge is probably due to the formation of dust in its outer envelope.
Its characteristics since 1992 are similar to those of R CrB-type
variables."


NOVA CASSIOPEIAE 1993
     Further visual magnitude estimates (cf. IAUC 5954): Mar. 30.78
UT, 15.9 (L. Szentasko, Veresegyhaz, Hungary); Apr. 4.80, 15.9
(Szentasko); 14.853, [14.4 (T. Vanmunster, Landen, Belgium); 15.09,
14.2: (Szentasko); 19.09, 13.7 (Szentasko); 19.115, 13.9 (Vanmunster);
21.07, 10.8 (Szentasko).


SUPERNOVA 1994I IN NGC 5194
     C. J. Chandler, National Radio Astronomy Observatory (NRAO); J.
A. Phillips, California Institute of Technology; and M. P. Rupen,
NRAO, report:  "Using the five-element millimeter interferometer at
the Owens Valley Radio Observatory, we observed SN 1994I at 99 GHz
on Apr. 16.24-16.56 UT.  No source was detected, the rms noise in the
image being 1.0 mJy/beam.  The absolute flux scale was established
by observations of Neptune and Uranus; the systematic uncertainty
is about 15 percent.  The supernova flux density at 3 mm has
declined by at least a factor of 3.7 over 11 days (cf. IAUC 5968);
assuming an explosion date of Mar. 31 and a power-law decline, this
implies a decay proportional to tE-1 or steeper.  This is consistent
with the rapid radio decline seen in type-Ib/c supernovae (Weiler
et al. 1986, Ap.J. 301, 790; Van Dyk et al. 1993, Ap.J. 419, L69)."


3C 279
    A. W. Neely, Silver City, NM; and M. Harvanek and J. Stocke,
University of Colorado, report that this quasar is brightening;
recent photometry:  Apr. 19 UT, V = 14.6 +/- 0.2; 21, 14.75 +/-
0.15; 22, 14.57 +/- 0.05.


1994 April 23                  (5978)            Daniel W. E. Green

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