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