IAU Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 8753: C/2006 S4; RS Oph

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 8752  SEARCH Read IAUC 8754

View IAUC 8753 in .dvi, .ps or .PDF format.
IAUC number


                                                  Circular No. 8753
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/2006 S4 (CHRISTENSEN)
     E. J. Christensen reports the discovery of another comet on
Catalina Sky Survey images obtained with the 0.68-m Schmidt
reflector (discovery observation tabulated below), the object
displaying a 1'.8 fan-shaped tail spanning p.a. approximately
210-250 deg in a stacked image of four 30-s exposures obtained in
poor seeing.  Following posting on the 'NEO Confirmation Page', M.
Tichy and J. Ticha write that their CCD images taken on Sept. 22.99
UT with the 1.06-m KLENOT Telescope at Klet show a diffuse 10" coma
and a tail in p.a. 260 deg.  P. Birtwhistle (Great Shefford,
Berkshire, U.K., 0.40-m f/6 Schmidt-Cassegrain reflector) reports
that his CCD images taken on Sept. 23.1 show a coma of diameter 10"
with central condensation and a tail 40" long in p.a. 245 deg.

     2006 UT             R.A. (2000) Decl.       Mag.
     Sept.22.37326    1 50 43.48   -16 25 58.4   16.8

The available astrometry, the following preliminary parabolic
orbital elements, and an ephemeris appear on MPEC 2006-S53.

     T = 2007 Apr. 26.414 TT          Peri. =  28.144
                                      Node  =  28.811   2000.0
     q = 2.89250 AU                   Incl. =  52.670


RS OPHIUCHI
     M. Orio and T. Nelson, Istituto Nazionale di Astrofisica and
University of Wisconsin, report that RS Oph (cf. IAUC 8671, 8695)
was observed with XMM-Newton on Sept. 6 for about 15 hr.  The count
rate in the range 0.1-10 keV had decreased by more than a factor of
1000 with respect to the last XMM-Newton observation on Apr. 6.
The unabsorbed flux is at least 4 x 10**-12 erg cm**-2 s**-1.
There is still significant continuum flux below 2 keV, but the
spectrum shows mainly strong emission lines.  With the RGS
spectrograph, several H-like and He-like emission lines of Mg, Ne,
and Fe are detected (most notably Ne VII at 2.478 nm, O VIII at
1.896 nm, Ne X at 1.213 nm, and Fe XVII at 1.501 nm).  The RGS
lines are red-shifted with a velocity not exceeding 500 km/s.
Despite the lack of significant flux above 2 keV, two emission
lines of the iron triplet K(alpha) complex are detected with EPIC
around 6.4-6.7 keV.

                      (C) Copyright 2006 CBAT
2006 September 23              (8753)            Daniel W. E. Green

Read IAUC 8752  SEARCH Read IAUC 8754

View IAUC 8753 in .dvi, .ps or .PDF format.


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


Valid HTML 4.01!