Circular No. 6990

Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION

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SUPERNOVA 1998dj in NGC 788 A. Piemonte, Pontificia Universidad Catolica; and F. Patat, European

Southern Observatory (ESO), report that they obtained a CCD spectrogram (30-min exposure, range 320–1010 nm, resolution 1.5 nm) of SN 1998dj (cf. IAUC 6986) with the ESO 1.5-m telescope (+ Boller & Chivens spectrograph) on Aug. 12.38 UT at La Silla. Inspection of the fully-reduced spectrum shows that this supernova is of type Ia, between 15 and 20 days after maximum; the Si II absorption feature is still present, together with the Ca II infrared triplet (plus H and K lines) and some Fe II features. The expansion velocities, derived from the above lines, range from 9000 to 12 000 km/s, consistent with the deduced phase.

COMET C/1998 J1 (SOHO)

Ephemeris extension to IAUC 6960 (elements MPC 32168):

1998 TT α_{2000}  δ_{2000}  Δ  r  ϵ  β  m_{1}
Aug. 15 10^{h}37.^{m}80 −53^{o}14.^{′}5 2.358 2.202 68.^{o}6 25.^{o}4 12.3
20 10 50.85 −54 21.5 2.458 2.280 67.9 24.3 12.5
25 11 03.78 −55 26.2 2.558 2.357 67.1 23.3 12.8
30 11 16.62 −56 29.0 2.658 2.433 66.2 22.3 13.0
Sept. 4 11 29.39 −57 30.0 2.756 2.508 65.3 21.4 13.2
9 11 42.13 −58 29.5 2.854 2.582 64.3 20.6 13.4
14 11 54.86 −59 27.5 2.951 2.655 63.3 19.8 13.6
19 12 07.61 −60 24.2 3.047 2.727 62.2 19.0 13.8
24 12 20.41 −61 19.8 3.141 2.798 61.1 18.3 14.0
29 12 33.26 −62 14.3 3.234 2.868 60.0 17.6 14.1
Oct. 4 12 46.21 −63 07.7 3.326 2.938 59.0 17.0 14.3
9 12 59.26 −64 00.0 3.416 3.007 57.9 16.3 14.4
14 13 12.46 −64 51.3 3.504 3.075 56.9 15.8 14.6
19 13 25.82 −65 41.4 3.591 3.142 55.9 15.2 14.7
24 13 39.36 −66 30.6 3.675 3.208 54.9 14.7 14.9
29 13 53.10 −67 18.6 3.757 3.274 54.1 14.2 15.0
Nov. 3 14 07.05 −68 05.5 3.836 3.340 53.3 13.8 15.2
8 14 21.26 −68 51.2 3.914 3.404 52.6 13.4 15.3
13 14 35.73 −69 35.7 3.988 3.469 52.0 13.0 15.4
1998 August 17  \begin{matrix}c \\ ◯ \end{matrix} Copyright 1998 CBAT  Daniel W. E. Green