THE ASTRONOMICAL JOURNAL    VOLUME 107, NUMBER 3, PAGE 1453          APRIL 1994

     LIGHT CURVES OF SN 1993J FROM THE KECK NORTHEAST ASTRONOMY CONSORTIUM

                                 P. J. BENSON

     Whitin Observatory, Wellesley College, Wellesley, Massachusetts 02181
                  Electronic mail: pbenson@lucy.wellesley.edu

                    W. HERBST, J. J. SALZER, AND G. VINTON

   Van Vleck Observatory, Wesleyan University, Middletown, Connecticut 06457
  Electronic mail: bill@elysium.wesleyan.edu, slaz@parcha.astro.wesleyan.edu

                G. J. HANSON, S. J. RATCLIFF, AND P. F. WINKLER

                 Middlebury College, Middlebury, Vermont 05753
               Electronic mail: ratcliff@midd.cc.middlebury.edu,
                        winkler@midd.cc.middlebury.edu

                        D. M. ELMEGREEN AND F. CHROMEY

                 Vassar College, Poughkeepsie, New York 12601
    Electronic mail: elmegreen@vaxsar.vassar.edu, chromey@vaxsar.vassar.edu

                          C. STROM AND T. J. BALONEK

    Foggy Bottom Observatory, Colgate University, Hamilton, New York 13346
                 Electronic mail: tbalonek@center.colgate.edu

                                B. G. ELMEGREEN

      IBM Research Division, T. J. Watson Research Center, P.O. Box 218,
                       Yorktown Heights, New York 10598
                      Electronic mail: bge@watson.ibm.com

                                   ABSTRACT

    We present BVRI photometry of SN 1993J, as well as data on its likely
    progenitor.  The post-explosion data were obtained with CCDs attached to
    telescopes (aperture size 0.4 to 0.6 m) on the campuses of the Keck
    Northeast Astronomy Consortium members by the authors and their
    students.  Our data show that the supernova rose to a second maximum in
    all colors and has declined steadily since then.  This is unlike either
    the plateau or linear version of the typical Type II light curve.
    Except for the initial peak, the light curve bears a strong resemblance
    to SNe Ib, supporting suggestions that this is a Type IIb event. The
    position of the supernova, as measured on our images, agrees to within
    0.1 arcsec with the position of a faint, apparently stellar image on a
    CCD R image taken with the 0.9 m telescope at KPNO on 1992 October 2.
    The likely progenitor is also visible on B and I frames taken with the
    0.9 m Burrell Schmidt telescope of the Warner and Swasey Observatory,
    Case Western Reserve University, at KPNO in 1993 February.  Examination
    of a photograph of M81 taken on 1993 March 27.1 (UT) by an amateur
    astronomer allows us to set a constraint on its brightness at that time.