Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6952: NEAR-SUN COMETS; V4334 Sgr

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 6951 SEARCH Read IAUC 6953

View IAUC 6952 in .dvi or .ps format.
IAUC number 

                                                  Circular No. 6952
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)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


NEAR-SUN COMETS
     D. Biesecker, Space Applications Corporation, NASA Goddard Space
Flight Center, reports provisional data (reduced by G. V. Williams) on nine
more comets found in C3 coronagraphic data.  Except for the first comet
(2 deg from the sun at its closest with maximum tail length 0.5 deg), they
appear to be Kreutz sungrazers and were also observed by C2.  Orbit
computations are deferred until more definitive astrometry can be done.
Comets X/1998 G3, G4, K10 and K11 (these last two having 0.5-deg tails
and being among the brightest Kreutz comets, with K11 following K10 along
the Kreutz track 4 hr later) were discovered by K. Schenk; H2 and K9
(the latter not showing a tail) by S. Stezelberger; J2 and K8 by Biesecker;
and K7 by A. Vourlidas.

     1998 UT           R.A. (2000) Decl.
     Apr. 10.526       1 42.2      +12 06      X/1998 G3
          10.526       1 29.9      + 5 43      X/1998 G4
          29.113       2 45.5      +11 31      X/1998 H2
     May  10.323       3 21.5      +14 38      X/1998 J2
          16.406       3 42.0      +16 05      X/1998 K7
          19.240       3 49.7      +17 07      X/1998 K8
          27.742       4 23.0      +17 53      X/1998 K9
          31.073       4 37.0      +17 27      X/1998 K10
          30.706       4 39.1      +16 50      X/1998 K11


V4334 SAGITTARII
     D. K. Lynch, R. W. Russell and C. J. Rice, The Aerospace
Corporation; and M. Sitko, University of Cincinnati, report infrared
spectroscopy of V4334 Sgr (cf. IAUC 6322) with the Infrared
Telescope Facility (+ BASS, 3".2-diameter aperture) on
Mar. 21.56, 22.60 and May 12.5 UT: "The March spectra were
identical within the formal errors (5-10 percent), indicating little
or no change in 24 hr.  The spectra showed a smooth, featureless
continuum between 3 and 13 microns that was well fit by a grey body
at 1100 K.  Narrowband magnitudes L' (3.6 microns), M' (4.9 microns)
and N' (10.5 microns) were 3.25, 2.60 and 1.72, respectively.
The spectrum is consistent with thermal emission from a shell of
hot dust or a heavily reddened photosphere.  Given the C-rich nature
of the object (Duerbeck and Benetti 1996, Ap.J. 468, L111) and the
recent dust formation (IAUC 6825), carbonaceous grains are the most
likely source of emission.  On May 12.50 the spectrum was still
featureless but had brightened by about 0.1 mag at L', M' and N', and it
exhibited approximately the same temperature as in March."

                      (C) Copyright 1998 CBAT
1998 June 25                   (6952)              Brian G. Marsden

Read IAUC 6951 SEARCH Read IAUC 6953

View IAUC 6952 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!