Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6828: V1333 Aql; XTE J1858+034; 55P

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 6827  SEARCH Read IAUC 6829

View IAUC 6828 in .dvi or .ps format.
IAUC number

                                                 Circular No. 6828
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
Phone 617-495-7244/7440/7444 (for emergency use only)

     J. H. Swank and E. Smith, Goddard Space Flight Center (GSFC);
and A. M. Levine and R. Remillard, Massachusetts Institute of
Technology (MIT), on behalf on the RXTE ASM team at GSFC and MIT,
report that the low-mass x-ray binary Aql X-1 (= V1333 Aql) has
started another x-ray outburst.  In real-time results from the RXTE
All Sky Monitor, the daily average flux levels in the band 2-12 keV
are:  Feb. 27, about 22 mCrab; 28, 36; Mar. 1, 59; 2, 100; 3, 127.
Pointed observations with the PCA began on Mar. 3 and confirm the
ASM results.  Observations at other wavelengths are encouraged.

XTE J1858+034
     F. E. Marshall, Goddard Space Flight Center; D. Chakrabarty,
Massachusetts Institute of Technology; and M. H. Finger, Marshall
Space Flight Center, report an improved position for XTE J1858+034
(IAUC 6826) of R.A. = 18h58m.6, Decl. = +3o21' (equinox 2000.0),
with an estimated 90-percent confidence error radius of 2'.5, based
on repeated scans across the source with the PCA on RXTE.  The flux
(2-10 keV) on Feb. 28.9 UT was 4 mCrab.

     D. K. Lynch and R. W. Russell, Aerospace Corporation; and M.
Sitko, University of Cincinnati, report observations of comets 55P,
103P and 69P using BASS on the NASA Infrared Telescope Facility.
The heliocentric distances of the comets were 1.03, 1.24, and 2.01
AU, respectively, with 55P approaching and 103P and 69P receding
from the sun.  Comet 55P/Tempel-Tuttle had an N magnitude of 4.0
+/- 0.12 on Feb. 8.25 UT.  The spectrum showed little evidence of
silicate emission and was well fit with a single 330-K blackbody
between 3 and 13 microns, some 60 K above the equilibrium blackbody
temperature of 274 K; observations on Feb. 9.25 showed this comet
to be unchanged from the previous night within the formal
uncertainties.  Comet 103P/Hartley 2 had an N magnitude of 4.8 +/-
0.2 on Feb. 9.25 and showed a weak silicate emission feature rising
about 15 percent above the continuum; the 8-13-micron color
temperature was 320 K, about 70 K above the blackbody equilibrium
temperature of 250 K for a dust particle at the computed
heliocentric distance.  Comet 69P/Taylor had an N magnitude of 4.5
+/- 0.20 on Feb. 9.4 and showed a small infrared excess indicative
of silicate emission; the 8-13-micron color temperature was 250 K,
again about 50 K above the blackbody equilibrium temperature.

                      (C) Copyright 1998 CBAT
1998 March 3                   (6828)            Daniel W. E. Green

Read IAUC 6827  SEARCH Read IAUC 6829

View IAUC 6828 in .dvi or .ps format.

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

Valid HTML 4.01!