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IAUC 7623: 2001 J1; 1987A

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                                                  Circular No. 7623
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)

COMET 2001 J1
     S. Pravdo, E. Helin, and K. Lawrence, Jet Propulsion
Laboratory, report the discovery of a comet by NEAT on CCD images
taken with the 1.2-m reflector at Haleakala.  The object appears
diffuse also on confirming CCD observations taken by L. Sarounova
at Ondrejov (coma diameter about 15") and by M. Tichy and J. Ticha
at Klet (coma diameter about 8"-10").

     2001 UT             R.A. (2000) Decl.        m1    Observer
     May  11.25299    8 38 28.54   +13 37 10.7   19.9   NEAT
          11.83708    8 41 23.41   +13 31 55.0   17.3   Sarounova
          11.85397    8 41 28.03   +13 31 49.7   17.1   Tichy

     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 (HST) STIS F28X50LP imaging and G750M
spectroscopy (52" x 2" slit) were obtained on Apr. 27 and compared
to earlier STIS observations.  Using the notation of Lawrence et
al. (2000, Ap.J. 537, 123), all nine spots reported on IAUC 7520
are reconfirmed, and of the four marginal detections reported
therein, three are clearly detectable in imaging and the H-alpha
spectrum, which we report with designation, p.a., radius, and the
F28x50LP flux (counts/s):  HS 12-050, 50 deg, 0".63, 13.0; HS
13-165, 165 deg, 0".52, 2.3; HS 14-249, 249 deg, 0".72, 9.2.  The
fourth spot reported on IAUC 7520 remains marginally detected in
the H-alpha spectrum at p.a. about 310 deg.  HS 1-029, HS 10-040,
and HS 12-050 are strongly blended; however, crowded-field
photometric techniques indicate that HS 1-029 has brightened by <
10 percent since Nov. 2000, revealing a distinct break in its light
curve.  The brightening rate of HS 2-104, HS 3-126, and HS 4-091
may be decelerating, as well.  HS 11-355 and 12-050, first
identified in Nov. 2000, have each brightened more in six months
than HS 4-091 has since Jan. 1999, and HS 2-104 is now nearly half
as bright as HS 1-029, demonstrating that the spots do not evolve
uniformly.  The remnant of SN 1987A has rapidly made the transition
from a few, restricted hot spots to having many interaction sites
distributed around the full circumference of the ER; many of these
are unresolved and blended at the resolution of HST.  Frequent
monitoring is strongly recommended, with observations tailored to
sample the entire interaction region."

                      (C) Copyright 2001 CBAT
2001 May 11                    (7623)            Daniel W. E. Green

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