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\IBVShead{4146}{13 January 1995}

\centerline{\ft OBSERVATIONS OF SN\,1993ad}
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\begintext

      Supernova (SN) 1993ad in IC 1501 was discovered by Pollas
  (1993) on November 7, 1993.  Pollas also reported the brightness
  estimate $B = 18^m$ at discovery date and the offsets from the
  nucleus of the parent galaxy
  $13^{\prime\prime}$ east and
  22\farcs 7 south.
    \par Spectrogram of SN\,1993ad was obtained on Nov. 10 by
  Cappellaro and Della Valle (1993). It showed
  that SN was of type II at a very early stage.
  Narrow emission lines of the Balmer series from
  H$_\alpha$ to H$_\varepsilon$  superimposed on a very
  blue continuum were observed.
   \par  It was also noted that spectrum of SN\,1983K,
  obtained ten days before maximum, was similar to that of
  SN 1993ad. Preliminary  photometry gave  $B = 16.3$,
  $B-V=-0.3$, $V-R=0.0$  on
  Nov. 10.1 UT.
     \par Four plates of SN\,1993ad were obtained with the 40-cm astrograph
  at Sternberg  Astronomical Institute Crimean Station.
  The brightness estimates are reported in Table I.
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{\baselineskip 15 pt
\hbox{\kern 7.5 true cm  Table I.}
    $$\vbox{\offinterlineskip
    \hrule
    \halign{&\vrule#&
      \strut\quad\hfil#\quad\cr
    height2pt&\omit&&\omit&&\omit&\cr
    &Date\hfil&& J.D.\hfil&& $B$\hfil &\cr
    & \hfil&&2440000+ \hfil&& \hfil &\cr
    height2pt&\omit&&\omit&&\omit&\cr
    \noalign{\hrule}
    height2pt&\omit&&\omit&&\omit&\cr
       & Nov 14.74 &&  9306.24 &&  16.24 &\cr
       & Nov 15.76 &&  9307.26 &&  16.26 &\cr
       & Nov 17.75 &&  9309.25 &&  16.45 &\cr
       & Nov 18.83 &&  9310.33 &&  16.37 &\cr
    height2pt&\omit&&\omit&&\omit&\cr}
    \hrule}$$}

  The light curve is shown in Figure 1.
  We can estimate the date and magnitude of maximum brightness:
              $ B_{max} = 16.1  $ on
   JD 2449303  (November 11).
     \par According to the RC3 the parent galaxy type is Sbc, the radial
  velocity $ v = 5165~$km~s$^{-1} $,
  and galactic absorption
  $ A_b = 0.12. $  As the SN was very blue near maximum, the absorption
  in the parent galaxy should be negligible and we can estimate
  the absolute magnitude at maximum  $ M_B = -18.2 $
  (with  $ H_0 = 75 $ km  s$^{-1}$ Mpc$^{-1}$).
  This means that SN\,1993ad was fainter than SN 1979C and 1983K
  ($ M_B = -19.6 $), but significantly brighter than average
  type II SNe.

    \par   The work was partly supported by
     Russian Foundation for Fundamental Research grants No. 93-02-17108,
  93-02-17114 and by grant No. MPP000 from the International Science
  Foundation.

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\centerline{\epsffile{4146-f1.ps}}

\centerline{Figure 1. Light curve of SN\,1993ad. Dots -- our data, circles -- data from the literature.}

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\beginauthors
\authorsrightcol

D. YU. TSVETKOV

N. N.  PAVLYUK


Sternberg Astronomical Institute

of Moscow University

13, Universitetskij Prosp.

Moscow 119899, Russia

E-mail:

tsvetkov@sai.msu.su                                    %email


pavlyuk@sai.msu.su                                     %email


\endauthors
\references
 Cappellaro, E., Della Valle, M., 1993, {\it IAU Circ.}, No.\,5887.

 Pollas, C., 1993, {\it IAU Circ.}, No.\,5887.


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