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IAUC 7520: 1987A; C/2000 V1 and C/2000 V2

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IAUC number

                                                  Circular No. 7520
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 617-495-7440/7244/7444 (for emergency use only)

     B. Sugerman, S. Lawrence, and A. Crotts, Columbia University,
report on evolution and new structure in the ejecta's interaction
with the inner equatorial ring (ER) of the remnant of SN 1987A:
"Hubble Space Telescope STIS F28X50LP imaging and G750M
spectroscopy (52" x 2" slit) were obtained on Oct. 29 and Nov. 3
and compared to earlier STIS observations.  Using the notation of
Lawrence et al. (2000, Ap.J. 537, 123), the first seven hot spots
are reconfirmed, and lightcurves of spots HS 2-104, HS 3-126, HS
4-091 and HS 5-139 (all first detectable between Nov. 1998 and Jan.
1999) reveal that they do not evolve uniformly.  HS 2-104 was a
factor of 2 fainter than HS 3-126 until Oct. 1999, but it is a
factor of 2 brighter in Nov. 2000.  HS 5-139 has increased sixfold
in brightness between May and Nov. 2000, while HS 4-091 has
increased by a factor of only 1.4.  Two new spots, detected in
imaging and the H-alpha spectrum, are reported as follows with
designation, p.a., radius, and the STIS flux (counts/s) for the ER:
HS 10-040, 40 deg, 0".64, 7.8 +/- 1.0; HS 11-355, 355 deg, 0".52,
2.0 +/- 0.4.  HS 10-040 is detectable as early as Oct. 1999, and
the 'faint, asymmetric extension' of HS 1-029 reported on IAUC 7419
is probably best explained by this distinct interaction site just
east of HS 1-029.  The radial positions and slow evolution of spots
HS 8-064 and HS 9-075 (detected at low levels by Lawrence et al.
2000) appear more consistent with reverse-shock emission, rather
than ejecta-ER interaction.  Additional brightening (at low levels
consistent with known spots at very early times but requiring
confirmation) is detected at p.a. 49 deg, 174 deg, 248 deg, and 314

COMETS C/2000 V1 and C/2000 V2 (SOHO)
     Further to IAUC 7514 and 7485, D. Hammer reports his
measurements for two additional Kreutz sungrazing comets imaged
with the SOHO spacecraft; C/2000 V1 was found by M. Boschat, and
C/2000 V2 was found by D. Biesecker.  Both comets were seen in the
C2 coronagraph, but only only C/2000 V1 was also visible with the
C3 instrument.  The reduced observations and orbital elements by
B. G. Marsden are given on MPEC 2000-V35.

    Comet         2000 UT           R.A. (2000) Decl.
    C/2000 V1     Nov.  4.471      14 30.2      -17 29
    C/2000 V2           5.643      14 42.1      -17 24

                      (C) Copyright 2000 CBAT
2000 November 17               (7520)            Daniel W. E. Green

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