Central Bureau for Astronomical Telegrams
IAUC 5643: EU 1737-132; 1992t
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Circular No. 5643
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
EU 1737-132
S. Brandt, A. J. Castro-Tirado, and N. Lund report: "A new x-
ray transient in Serpens Cauda has been discovered by the WATCH
wide-field monitor on the ESA EURECA satellite. The transient was
first observed on Oct. 11, at R.A. = 17h37m20s, Decl. = -13 15'.0
(equinox 1950.0; error radius 45'). The source brightness at the
time of discovery was about 500 mCrab (above 6 keV), and remained
at about this level at least until Oct. 18. In the spectral band
between 6 and 15 keV, the source is now only slightly harder than
that of Sco X-1, though during the first two days of the outburst
the spectrum was harder. Our limited sensitivity does not allow us
to detect the source above 15 keV. The source may be similar to
that of dwarf x-ray transients such as N Mus 1991 and GRO J0422+32.
Follow up at other wavelengths is encouraged."
PERIODIC COMET SWIFT-TUTTLE (1992t)
P. Colom, D. Bockelee-Morvan, G. Bourgois, J. Crovisier, E.
Gerard, and L. Jorda, Paris-Meudon Observatory, communicate: "The
main lines of the OH radical at 1667 and 1665 MHz were detected in
emission in P/Swift-Tuttle on Oct. 15 with the Nancay Radio Telescope.
For the period Oct. 16-20, the 1667-MHz profile has a peak
flux density of 86 +/- 14 mJy, a FWHM of 2 km/s, and is blueshifted
by 0.3 km/s with respect to the radial velocity of the nucleus.
The line area of 184 +/- 17 mJy km/s corresponds to an OH
production rate of 8 x 10E28 molecules/s."
J. V. Scotti, University of Arizona, reports that CCD images
were obtained of this comet on Oct. 18.1, 19.1, and 21.1 UT with
the Spacewatch telescope, showing an ion tail extending at least
15' toward the north-northeast. There was a noticeable increase in
inner coma activity, as well as in overall brightness, between Oct.
18.1 and 19.1. On Oct. 21.097 UT, there was a 10'.5 coma surrounding
an inner coma that is asymmetrical toward the west (though the
overall coma is nearly circular). A fan-shaped jet to the west
dissipated slightly between Oct. 18 and 21, and the tail was a bit
fainter on Oct. 21 than on previous nights. The fan-shaped jet
structure on Oct. 21 runs from p.a. 242 to 313 deg; the main tail
extends toward p.a. 24 deg, and there are two faint streamers
bracketing the tail at p.a. 9 and 50 deg, each extending about 5'
and perhaps further.
1992 October 22 (5643) Daniel W. E. Green
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