Central Bureau for Astronomical Telegrams
IAUC 5017: 1990c; OAO 1657-415; 1990a
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Circular No. 5017
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 or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
COMET LEVY (1990c)
David H. Levy reports his discovery of a comet. The
following visual observations are available:
1990 UT R.A. (1950) Decl. m1 Observer
May 20.44 23 54.3 +27 30 9.6 Levy
21.426 23 55.07 +27 33.7 10.1 Hale
21.442 23 55.0 +27 37 10.5 Morris
21.462 23 55.10 +27 34.2 Hale
D. H. Levy (Tucson, AZ). 0.4-m reflector. Tail 2' to southwest.
A. Hale (Las Cruces, NM). 0.41-m reflector. Coma diameter about
1', moderately condensed.
C. S. Morris (Pine Mountain Club, CA). 0.26-m reflector. Coma
diameter 1'.5, nearly stellar condensation.
OAO 1657-415
S. Mereghetti, Centre d'Etudes Spatiales des Rayonnements
(CESR), Toulouse, communicates the following for the Granat Team
(CESR; Service d'Astrophysique, Centre d'Etudes Nucleaires de
Saclay, Gif sur Yvette; and Space Research Institute, Academy of
Sciences, Moscow): "The x-ray pulsar OAO 1657-415 has been
observed by the SIGMA and ART-P telescopes onboard the orbiting
Granat observatory on Mar. 27-28. The source was detected in the
x-ray band by ART-P, and at energies > 35 keV by the SIGMA hard
x-ray/gamma-ray telescope. The pulse period at the solar system
barycenter was 37.853 +/- 0.002 s. Since its discovery in 1978,
this source has been constantly spinning up, with (dP/dt)/P about
-1 to -5 x 10E-3 yrE-1. The results obtained with Granat show that
a change in the accretion torque has recently occurred, causing the
source to enter a phase of period spin-down. Comparison with the
previous Ginga measurement in 1988 Mar. yields (dP/dt)/P = 1.3 x
10E-3 yrE-1. Other x-ray observations of OAO 1657-415 are urged."
PERIODIC COMET WILD 4 (1990a)
Total visual magnitude estimates: Apr. 24.57 UT, 12.5 (J.
Kobayashi, Kumamoto, Japan, 0.31-m reflector); May 14.48, 13.0 (A.
Pearce, Scarborough, W. Australia, 0.41-m reflector); 21.22, 12.7
(A. Hale, Las Cruces, NM, 0.41-m reflector).
1990 May 21 (5017) Daniel W. E. Green
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