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IAUC 6556: 1997Y; C/1995 O1; GRO J2058+42

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                                                 Circular No. 6556
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)


SUPERNOVA 1997Y IN NGC 4675
     W.-d. Li, Y.-l. Qiu, Q.-y. Qiao, and J.-y. Hu, Beijing
Astronomical Observatory (BAO), on behalf of the BAO supernova
survey, report the discovery of an apparent supernova on unfiltered
CCD images of NGC 4675 taken on Feb. 2 and 7 with the BAO 0.60-m
reflector.  SN 1997Y is located at R.A. = 12h45m31s.40, Decl. =
+54o44'17".0 (equinox 2000.0), which is 7".5 west and 1".6 north of
the galaxy's nucleus.  The object brightened from mag approximately
14.8 on Feb. 2 to 14.4 on Feb. 7.  Unfiltered CCD images of the
same field taken on Jan. 24 showed no star at the position of SN
1997Y.


COMET C/1995 O1 (HALE-BOPP)
     D. Lynch and R. Russell, The Aerospace Corporation, report:
"The 11.2-micron emission feature of comet C/1995 O1 is increasing
in strength as the comet approaches the sun.  Data taken at the
Infrared Telescope Facility and at Mt. Lemmon with the Aerospace
BASS spectrograph in 1996 July, Oct. and Nov. reveal that the
feature's contrast above the local 10-11-micron silicate continuum
increased from a few percent in July (r = 3.7 AU) to approximately
15 percent in Nov. (r = 2.25 AU).  We also report the detection of
a broad (0.2-micron), weak (few percent) emission feature at 11.8
microns.  Observers are urged to concentrate on obtaining high S/N-
ratio spectra of the comet in the region 8-13 microns in order to
monitor the evolution of the features with heliocentric distance."


GRO J2058+42
     R. Corbet, Goddard Space Flight Center (GSFC) and Universities
Space Research Association, on behalf on the RXTE ASM team at GSFC
and the Massachusetts Institute of Technology (MIT); A. Peele, GSFC
and National Research Council; and R. Remillard, MIT and RXTE ASM
team, report:  "Analysis of the RXTE ASM light curve of the 195.6-s
x-ray pulsar GRO J2058+42 obtained between 1996 Jan. 5 and 1997
Jan. 30 shows the presence of a modulation with a period of
approximately 54 days.  This period is half the 110-day period
reported from BATSE observations (IAUC 6514), although the ASM is
sensitive to lower-energy x-rays in the range 2-12 keV.  A sine-
wave fit to the light curve yields a period of 53.9 +/- 1.2 days
with epoch of maximum flux at 1996 Oct. 2.4 UT +/- 2.0 days.  The
mean x-ray flux during this period was approximately 3 mCrab with
outbursts reaching approximately 8 mCrab."

                      (C) Copyright 1997 CBAT
1997 February 8                (6556)            Daniel W. E. Green

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