Circular No. 7040

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

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COMET C/1998 U3 (JÄGER) Ninety-one precise positions that appear on MPEC 1998-U26, spanning

Oct. 24–27, yield the following preliminary parabolic orbital elements. This comet is likely of short period.

T = 1998 Dec. 9.919 TT  ω = 138.^{o}252
Ω = 313.194 }2000.0
q = 2.66631 AU  i = 17.842
1998TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
Oct. 14 6^{h}31.^{m}93 +41^{o}23.^{′}7 2.323 2.733 103.^{o}5 20.^{o}8 12.7
19 6 37.90 +41 28.6 2.258 2.722 107.0 20.5 12.6
24 6 43.29 +41 32.4 2.195 2.712 110.7 20.1 12.5
29 6 48.03 +41 35.0 2.135 2.703 114.5 19.5 12.5
Nov. 3 6 52.10 +41 36.3 2.077 2.694 118.4 18.9 12.4
8 6 55.46 +41 36.3 2.022 2.687 122.4 18.1 12.3
13 6 58.07 +41 34.9 1.971 2.681 126.6 17.2 12.3
18 6 59.89 +41 31.6 1.923 2.676 130.9 16.2 12.2
23 7 00.93 +41 26.3 1.879 2.672 135.2 15.1 12.1
28 7 01.19 +41 18.5 1.840 2.669 139.7 13.8 12.1
Dec. 3 7 00.72 +41 07.7 1.805 2.667 144.2 12.5 12.0
8 6 59.56 +40 53.7 1.775 2.666 148.6 11.1 12.0
13 6 57.79 +40 35.9 1.752 2.667 153.0  9.6 12.0

Total visual magnitude and coma-diameter estimates: Oct. 26.01 UT, 12.2, 1′.7 (K. Hornoch, Lelekovice, Czech Republic, 0.13-m reflector); 26.42, 12.3, 2′ (A. Hale, Cloudcroft, NM, 0.41-m reflector); 26.97, 12.3, 1′.5 (R. J. Bouma, Groningen, The Netherlands, 0.25-m reflector); 27.17, 12.3, 1′.0 (A. Pereira, Cabo da Roca, Portugal, 0.25-m reflector).

AX J0049–732 K. Imanishi, J. Yokogawa, and K. Koyama, Kyoto University, write:

“An ASCA observation made on 1997 Nov. 13 detected x-ray pulsations with a period of 9.1321 ± 0.0004 s from a source at α = 0^{h}49^{m}23^{s}, δ = −73^{o}12′38′′ (equinox 2000.0; ± 1′ at 90-percent confidence), designated as AX J0049–732. The x-ray flux at 2–10 keV was ∼ 8 × 10^{−13} erg s^{−1} cm^{−2}.”

1998 October 27  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Daniel W. E. Green