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IAUC 6640: P/1997 H1; 1997by

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                                                  Circular No. 6640
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


COMET P/1997 H1 (McNAUGHT-HUGHES)
     J. V. Scotti, Lunar and Planetary Laboratory; and A. Nakamura,
Kuma Kogen Astronomical Observatory, have independently recovered
comet P/1991 S1 (= 1991y = 1991 IX) as shown below.  The indicated
correction to the prediction by the undersigned on MPC 25183
(ephemeris on MPC 27943) is Delta T = +0.02 day.

     1997 UT             R.A. (2000) Decl.        m1    Observer
     Apr. 16.44773   15 22 59.38   -10 31 03.0   20.6   Scotti
          16.47023   15 22 58.57   -10 31 00.0   20.6     "
          16.48596   15 22 58.04   -10 30 58.0   20.1     "
          29.65512   15 14 06.69   - 9 58 52.3   20.3   Nakamura
          29.66510   15 14 06.18   - 9 58 50.8            "
          29.67682   15 14 05.69   - 9 58 48.6            "

J. V. Scotti and J. Larsen (Kitt Peak).  0.9-m Spacewatch telescope.
A. Nakamura (Kuma Kogen).  0.60-m f/6.0 Ritchey-Chretien.  Comet
   essentially stellar in appearance.  Communicated by S. Nakano.

     Improved orbital elements from 33 observations 1991-1997:

                    Epoch = 1998 Mar.  8.0 TT
     T = 1998 Feb. 23.7633 TT         Peri. = 224.3657
     e = 0.404125                     Node  =  89.9731  2000.0
     q = 2.116237 AU                  Incl. =   7.3033
       a =  3.551479 AU    n = 0.1472619    P =   6.693 years


SUPERNOVA 1997by IN ANONYMOUS GALAXY
     M. Turatto and S. Benetti, European Southern Observatory, report:
"We obtained a spectrogram (range 320-1000 nm, resolution 1.2 nm) on Apr.
30.18 UT with the 1.5-m telescope at La Silla.  The spectrum of the new
supernova closely resembles that of the prototypal SN 1994D a couple of
days before maximum, thus indicating that SN 1997by is a normal type Ia.
Strong absorption lines superimposed on a blue continuum are identified
as due to Si II, S II, Fe III and Ca II.  The redshift of the parent
galaxy Abell 1736 (measured at the SN position using Na I, Mg I and the
G band) is z = 0.045.  This redshift implies a photospheric velocity
(deduced from the Si II line) of 10 760 km/s for SN 1997by, also similar
to the value for SN 1994D."

                      (C) Copyright 1997 CBAT
1997 April 30                  (6640)              Brian G. Marsden

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