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IAUC 7360: 2000F; 1987A

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                                                  Circular No. 7360
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)

     P. Garnavich, University of Notre Dame; and S. Jha, P.
Challis, and R. Kirshner, Harvard-Smithsonian Center for
Astrophysics, report that a spectrum of 2000F (cf. IAUC 7353) was
obtained by E. Falco on Feb. 2.1 UT with the F. L. Whipple
Observatory 1.5-m telescope.  The spectrum was taken under poor
conditions and is of low signal-to-noise but suggests that the
supernova is of type Ic.  The continuum is red; a broad absorption
is seen at a rest wavelength of 570 nm and a weak emission band is
visible at 460 nm.  Narrow H-alpha emission from the host galaxy
provides a recession velocity of 5850 km/s.
     Preliminary CCD photometry of SN 2000F by K. Krisciunas,
University of Washington, and F. Deglman, Apache Point Observatory
(APO), using the APO 3.5-m telescope:  Feb. 4.09 UT, V = 18.69, B-V
= +1.88, V-R = +0.78, V-I = +1.33 (uncertainties roughly +/- 0.03);
Feb. 7.09, 18.87 +/- 0.02, +1.98 +/- 0.06, +0.84 +/- 0.02, +1.45
+/- 0.02.

     Garnavich, Kirshner, and Challis, on behalf of the Supernova
Intensive Study team, also report that Hubble Space Telescope (HST)
Wide Field/Planetary Camera 2 (WFPC2) images of SN 1987A were
obtained on Feb. 2 UT, which show that additional bright spots have
developed around the inner ring since the previous HST imaging in
1999 April.  The 'structure' on the southeast quadrant of the ring
reported by Bouchet et al. (IAUC 7354) is resolved into four
individual spots that appear unresolved at the WFPC2 resolution.
An additional spot is developing in the southwest quadrant, and
there appear to be three faint spots forming on the northwest side,
but these are at the limit of detectability.  The original region
of activity ('spot 1'; see below) continues to brighten, but at a
slower rate than previously seen (IAUC 7102).  The distance and
p.a. from the supernova position and H-alpha fluxes (in units of
10**-15 erg cm**-2 s**-1) for each spot are as follows:  spot 1,
0".58 in p.a. 29 deg, 13.8; spot 2, 0".73 in p.a. 91 deg, 1.3; spot
3, 0".70 in p.a. 106 deg, 1.6; spot 4, 0".63 in p.a. 122 deg, 2.0;
spot 5, 0".58 in p.a. 139 deg, 0.4; spot 6, 0".66 in p.a. 229 deg,
0.9.  The current H-alpha flux of spot 4 is similar to that of spot
1 in early 1997.  Spot 6 is within 0".15 of a 20th-magnitude star
projected on the ring (Plait et al. 1995, Ap.J. 439, 730).  The
sudden increase in activity suggests that the full-scale collision
between the supernova ejecta and the circumstellar ring gas has
finally begun (e.g., McCray 1993, Ann. Rev. A.Ap. 31, 175).

                      (C) Copyright 2000 CBAT
2000 February 7                (7360)            Daniel W. E. Green

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