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IAUC 7491: 2000dj; V4633 Sgr

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                                                  Circular No. 7491
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)

     S. Benetti, A. Zacchei, I. Perez, M. Pedani, and A. Buzzoni,
Telescopio Nazionale Galileo (TNG), communicate:  "A fully reduced
CCD spectrum (range 350.4-812.7 nm, resolution 1.1 nm), obtained on
Sept. 15.10 UT with the TNG reflector (+ D.o.lo.res spectrograph),
shows SN 2000dj (cf. IAUC 7490) to be a type-II supernova around
maximum light.  The spectrum consists of a blue continuum with
superimposed P-Cyg lines of Ca II H and K and hydrogen.  The
average expansion velocity deduced from the minima of the Balmer
lines is 9800 km/s (a recession velocity for the parent galaxy of
4629 km/s has been obtained from NED database).  The absorption of
H-alpha line has a double profile with a secondary minimum measured
at 629.1 nm."
     M. Armstrong, Rolvenden, Kent, England, reports his
independent discovery of SN 2000dj at mag 17.0 on a 45-s CCD
exposure taken with a 0.30-m reflector on Sept. 11.011 UT in the
course of his supernova patrol (limiting mag 19.0).  He gives the
following position end figures (cf. IAUC 7490):  40s.63, 12".9.
The new object does not appear on images taken by Armstrong on 1999
Nov. 6 (limiting mag 19.5) or 2000 Aug. 28.987 (limiting mag 18.5),
nor does it appear on Palomar Sky Survey images taken on 1992 Oct.
31 (limiting mag 22.5) and 1989 Nov. 29 (limiting mag 20.8)

     R. J. Rudy, D. K. Lynch, S. Mazuk, and C. Venturini, The
Aerospace Corporation; R. C. Puetter, Center for Astrophysics and
Space Science, University of California at San Diego; and T.
Armstrong, Thomas K. Armstrong Development Corporation, report
0.8-2.5-micron spectrophotometry of V4633 Sgr = N Sgr 1998 using
the Shane 3-m telescope and the Aerospace Near Infrared Imaging
Spectrograph on July 21.36 UT, about 850 days after peak
brightness:  "V4633 Sgr has faded by more than a magnitude in the
past 11 months (see IAUC 7259).  J, H, and K magnitudes determined
from the spectrophotometry are 14.8, 14.4, and 13.8.  He II at
1.0124 microns exceeds He I 1.0830-microns in strength, indicating
that most of the helium is doubly ionized.  The strongest features
in the spectrum are the coronal lines of [Si VI] at 1.9629 microns
and [Ca VIII] at 2.3214 microns.  [Si VII] 2.4827-microns, and [S
VIII] 0.9913-micron have appeared in the last 11 months.
Surprisingly, the spectrum does not exhibit the large degree of
reddening expected given the object's galactic coordinates (l = 5.1
deg, b = -6.2 deg)."

                      (C) Copyright 2000 CBAT
2000 September 15              (7491)            Daniel W. E. Green

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