Circular No. 6930

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

Mailstop 18, 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)

          URL http://cfa-www.harvard.edu/iau/cbat.html

Phone 617-495-7244/7440/7444 (for emergency use only)

GRS 1915+105

E. B. Waltman, Naval Research Laboratory; and F. D. Ghigo, National Radio Astronomy Observatory, report that the Green Bank Interferometer has observed a flare in the microquasar GRS 1915+105 on June 3. Following an extended period in the plateau state, flux densities rose to 0.7 Jy at 2 GHz and 0.6 Jy at 8 GHz on June 3.4 UT. The public-domain data may

be accessed at http://www.gb.nrao.edu/gbint/GBINT.html.

COMET C/1998 J1 (SOHO)

Ephemeris extension to IAUC 6913 (elements MPEC 1998-L07):

1998TT α_{2000} δ_{2000} Δ r ϵ β m_{1}
June 6 6^{h}52.^{m}50 −21^{o}38.^{′}1 1.005 0.895 52.^{o}6 64.^{o}2  7.5
8 7 01.47 −23 44.9 1.037 0.942 54.6 61.5  7.8
10 7 10.12 −25 41.6 1.070 0.987 56.5 59.0  8.1
12 7 18.50 −27 29.2 1.104 1.032 58.1 56.7  8.4
14 7 26.62 −29 08.7 1.139 1.076 59.6 54.5  8.6
16 7 34.52 −30 40.8 1.174 1.119 60.9 52.5  8.8
18 7 42.21 −32 06.3 1.211 1.161 62.1 50.7  9.1
20 7 49.71 −33 25.9 1.247 1.203 63.2 49.0  9.3
22 7 57.02 −34 40.3 1.285 1.244 64.2 47.4  9.5
24 8 04.18 −35 50.0 1.323 1.285 65.1 45.9  9.7
26 8 11.19 −36 55.4 1.361 1.325 65.9 44.5  9.9
28 8 18.05 −37 57.1 1.399 1.364 66.6 43.1 10.1
30 8 24.79 −38 55.3 1.438 1.403 67.2 41.9 10.3
July 2 8 31.40 −39 50.4 1.477 1.442 67.8 40.8 10.4
4 8 37.90 −40 42.8 1.516 1.480 68.3 39.7 10.6
6 8 44.29 −41 32.6 1.555 1.517 68.7 38.6 10.8

COMET C/1998 H1 (STONEHOUSE)

Ephemeris extension to IAUC 6887 (elements MPC 31662):

1998TT α_{2000} δ_{2000} Δ r ϵ β m_{1}
June 6 12^{h}30.^{m}11 +49^{o}49.^{′}8 1.369 1.659 86.^{o}9 37.^{o}6 12.9
16 12 18.39 +50 33.1 1.611 1.724 78.4 35.3 13.4
26 12 13.53 +50 47.0 1.841 1.795 71.3 32.4 13.9
July 6 12 13.50 +50 48.4 2.053 1.874 65.4 29.6 14.3
16 12 16.96 +50 45.9 2.247 1.957 60.5 26.9 14.7
1998 June 3  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Daniel W. E. Green