Central Bureau for Astronomical Telegrams
IAUC 8695: P/2006 F4; 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 8696
.dvi,
.ps or
.PDF format.
Circular No. 8695
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 P/2006 F4 (SPACEWATCH)
R. S. McMillan, Lunar and Planetary Laboratory, reports the
Spacewatch discovery of a comet on CCD images taken by M. T. Read
and himself with the 0.9-m reflector, the object being diffuse with
a 6 deg" deg tail in p.a. 280 deg (discovery observation tabulated
below). A. C. Gilmore reports that images taken on Mar. 30.6 UT
with the Mt. John 1.0-m f/7.7 reflector show a moderately condensed
coma about 10" in diameter with a hint of a diffuse tail on the
west side. Astrometry and preliminary orbital elements [T = 2006
Apr. 15.1 TT, Peri. = 25.3 deg, Node = 184.4 deg, i = 12.5 deg
(equinox 2000.0), q = 2.362 AU, e = 0.349, P = 6.9 yr] appear on
MPEC 2006-F53.
2006 UT R.A. (2000) Decl. Mag.
Mar. 26.35589 14 19 57.50 - 6 55 40.7 19.9
RS OPHIUCHI
R. Gonzalez-Riestra, XMM-Newton Science Operation Centre,
European Space Agency; M. Orio, National Institute of Astrophysics
of Italy and University of Wisconsin; and E. Leibowitz, Tel Aviv
University, write that RS Oph was observed with XMM-Newton on Feb.
26 for 400 minutes and on Mar. 10 for 197 minutes. At both times,
prominent emission lines were observed with the RGS gratings, due
to H-like and He-like transitions of N, O, Mg, Ne, Si, and Fe. The
total flux was about 1.4 x 10**-10 erg/s in the first observation
and about 1.1 x 10**-10 erg/s in the second. Some emission lines
in the range 0.6-1.6 nm decreased in strength by the second
observation, while other lines in the region 1.7-3.3 nm became much
more prominent, especially O VII (1.897 nm) and N VIII (2.478 nm),
due to a decrease of the column density of neutral hydrogen to a
value not exceeding 3 x 10**21 cm**-2 on Mar. 10. The lines were
blueshifted by 1100-1400 km/s in the first observation and only by
a few hundred km/s in the second, and at both times, their full-
width-at-half-maximum corresponded to at least 2000 km/s. Both
EPIC-pn spectra showed also the Fe-K-alpha complex in emission, but
it was significantly stronger in the February spectrum. During the
second observation, after the first 2800 s, the EPIC-pn count-rate
in the range 0.15-0.50 keV quadrupled in approximately 1700 s, then
decreased by 40 percent in the following 1500 s and remained
approximately constant until the end. During the rise and fall,
the power spectrum shows a significant signal with a period of
35.685 s. The EPIC-pn count-rate in the range 1-10 keV had non-
correlated variations by 10 percent and no coherent oscillations.
(C) Copyright 2006 CBAT
2006 March 30 (8695) Daniel W. E. Green
Read IAUC 8696
.dvi,
.ps or
.PDF format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
