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IAUC 4774: 1989H, 1989I; SU UMa; 1989B

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                                                  Circular No. 4774
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 the
discoveries of two apparent supernovae found on plates exposed
with the CERGA Schmidt telescope.  SN 1989H, found on a plate
taken Feb. 7.16 UT, was at B = 20 and located in an H II region
of the south arm of MCG +6-30-64 (R.A. = 13h36m.4, Decl. = +32 32',
equinox 1950.0); the SN is 3".5 east and 16".3 south of the
galaxy's center.  Further magnitude estimates:  Feb. 8.20, R = 19.5;
9.15, R = 19.5; Mar. 11.09, B about [21.  A faint, less-stellar
object (probably an H II region) is visible at mag about 21 on the POSS
B plate in the location of SN 1989H.  SN 1989I, in an anonymous
galaxy, was found on plates taken Mar. 11.15 and 9.19 (B = 19)
by A. Maury and Pollas and was confirmed with the 2-m Pic du
Midi Observatory telescope on Apr. 2 by E. Davoust, A. Klotz, and
J. L. Nieto.  SN 1989I is located at R.A. = 14h34m15s.72, Decl. =
+14 53'09".1 (equinox 1950.0), and lies 3".4 west and 4".5 south
of the galaxy's center.

     A.  Udalski, York University, Toronto, and Warsaw University
Observatory, writes:  "Following notification by J. A. Mattei,
AAVSO, of the superoutburst of this dwarf nova (cf. IAUC 4773), I
obtained three 6-hr photometric observing runs of SU UMa using the
0.61-m/0.48-m twin photometric system of the David Dunlop Observatory
during Apr. 21-23.  Superhumps with an amplitude of about 0.2 mag
were discovered.  Based on timing of nine superhump maxima, the
preliminary superhump period is about 113.5 min.  The superhump
period is therefore about 3 percent longer than the orbital one
(Thorstensen et al. 1986, Ap.J. 309, 721), similar to that of
other SU UMa-type stars.  Discovery of superhumps in SU UMa
proves that the star is indeed a typical SU UMa-type dwarf nova
and a good prototype star for the whole class."
     Further visual magnitude estimates by P. Schmeer,
Bischmisheim, W. Germany:  Apr. 23.89 UT, 11.7; 25.02, 11.7.

     Further visual magnitude estimates (cf. IAUC 4772):
Apr. 11.50 UT, 15.8: (T. Kato, Kyoto, Japan); 22.10, 15.4 (R.
Bunge, Mansfield, OH).

1989 April 25                  (4774)             Daniel W. E. Green

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