Central Bureau for Astronomical Telegrams
IAUC 6334: C/1996 B2; GRO J1744-28
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Circular No. 6334
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
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)
Phone 617-495-7244/7440/7444 (for emergency use only)
COMET C/1996 B2 (HYAKUTAKE)
R. M. West, European Southern Observatory (ESO), reports that
an image of the complex tail system of C/1996 B2 was obtained by O.
Pizarro with the ESO 1-m Schmidt telescope at La Silla on Feb.
28.36 UT under good observing conditions. The following is a
description from an amplified reproduction of the 60-min Kodak Pan
4415 film (+ GG385 filter; 390-700 nm) by H.-H. Heyer (ESO,
Garching): "A broad and featureless dust tail is seen at p.a. 280
deg until 40' from the nucleus. A narrow ion tail extends to 20'
at p.a. 289 deg, where it branches into two main components -- a
broader one at p.a. 289 deg with complex structure (and strong
kinks at 35' and 96') and total length exceeding 160' (plate edge),
and a narrow one with sharp borders between p.a. 300 and 301 deg to
about 100' distance. There are several streamers in the interval
p.a. 305-315 deg, some reaching to about 25'."
Total visual magnitude and coma-diameter estimates: Mar.
1.77 UT, 6.2, - (R. H. McNaught, Siding Spring Observatory, naked
eye); 2.53, 5.8, 15' (C. S. Morris, Whitaker Peak, CA, 10x50
binoculars; 1.75 deg tail in p.a. 278 deg); 3.78, 5.7, - (G.
Garradd, Loomberah, Australia, naked eye); 4.24, 5.5, 13' (A.
Pereira, Cabo da Roca, Portugal, 9x34 binoculars).
GRO J1744-28
M. J. Stark, University of Maryland at College Park, and the
Laboratory for High Energy Astrophysics, Goddard Space Flight
Center (LHEA/GSFC); A. Baykal, National Research Council and LHEA/
GSFC; T. Strohmayer, Universities Space Research Association and
LHEA/GSFC; and J. H. Swank, LHEA/GSFC, write: "We report a
correction to IAUC 6324 and confirmation with XTE of the result
reported by Jung et al. on IAUC 6321. On IAUC 6324, we reported
an incorrect direction of the phase shift in the pulsar arrival
times of GRO J1744-28. Following each of the x-ray bursts, we
reported as an advance in the pulse arrival time what is actually a
lag. We reported the correct magnitude (25 ms) and duration (onset
< 25 s; decay about 1500 s). Combining the data from seven bursts
observed on Jan. 18, we have confirmed a lag during the bursts in
pulse-arrival times of 15 percent. This lag persists for the
duration of the burst (8-10 s) in the majority of pulses, which
keep the same shape. For a few periods at high intensity, the
pulse is not present or is doubly peaked. After the burst, the
pulse-arrival time lag drops to 5 percent within a few seconds and
decays further in about 1500 s, as we reported earlier."
(C) Copyright 1996 CBAT
1996 March 4 (6334) Daniel W. E. Green
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