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IAUC 7694: C/2001 Q3; V4643 Sgr

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                                                  Circular No. 7694
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)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)


COMET C/2001 Q3 (SOHO)
     Further to IAUC 7689, D. Hammer reports astrometric
measurements of a comet found by Chen Dong Hua on SOHO website
images.  The object was first detected (at the position given
below) in LASCO C2 coronagraph images, moving southward from
directly underneath the occulter; the comet brightened and showed a
nice tail before entering the C3 field-of-view, where it began to
fade, as indicated by the following additional V magnitudes
provided by D. Biesecker and Hammer:  Aug. 25.393 UT, 7.6; 25.463,
7.4; 25.977, 5.7; 26.102, 4.8; 26.221, 5.2; 26.227, 4.6; 26.446,
5.8; 26.811, 8.0.

     2001 UT           R.A. (2000) Decl.        m1
     Aug. 25.338      10 15.1      +12 35       8.3

The reduced positions, the following orbital elements, and an
ephemeris by B. G. Marsden appear on MPEC 2001-Q60.

     T = 2001 Aug. 26.51 TT           Peri. = 268.11
                                      Node  = 155.03    2000.0
     q = 0.0373 AU                    Incl. = 106.63


V4643 SAGITTARII
     N. M. Ashok and D. P. K. Banerjee, Physical Research
Laboratory, Ahmedabad; and W. P. Varricatt, Joint Astronomy Centre,
Hilo, report spectroscopy of V4643 Sgr at 1.05-2.55 microns with
the U.K. Infrared Telescope (+ CGS4) in June and on Aug. 12:  "The
K-band spectrum taken on June 16 is dominated by the Si VI and VII
lines at 1.963 and 2.476 microns, respectively, indicating that the
nova has entered the coronal phase.  These lines show multiple
components and large expansion velocity (FWZI = 9000-10000 km/s).
The Ca VIII line at 2.323 microns is also detected.  The J-band
spectrum taken on June 28 and the H-band spectrum taken on June 29
show that the H I emission lines at Paschen-beta, Paschen-gamma,
and Brackett_10 to Brackett_14 have considerably weakened, and the
O I line at 1.128 microns has disappeared (having been present in
the Mt. Abu spectra taken on Mar. 3; IAUC 7599).  The J-, H-, and
K-band spectra of Aug. 12 are similar to those of June, except that
the Si VI and VII lines have weakened considerably, and Ca VIII
line has faded below detection limit."

                      (C) Copyright 2001 CBAT
2001 August 28                 (7694)            Daniel W. E. Green

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