Central Bureau for Astronomical Telegrams
IAUC 7000: 1998dq; XTE J2123-058; 9P
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 7001
.dvi or
.ps format.
Circular No. 7000
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)
SUPERNOVA 1998dq IN NGC 6754
F. Patat and P. Leisy, European Southern Observatory (ESO);
and A. Piemonte, Pontificia Universidad Catolica, write: "We
obtained a CCD spectrogram (10-min exposure, range 340-745 nm,
resolution 2.6 nm) of SN 1998dq (cf. IAUC 6998) on Aug. 27.00 UT
with the ESO 3.6-m telescope (+ EFOSC2) at La Silla. A full
reduction of the spectrum shows a strong Si II 635.5-nm feature, a
multitude of Fe II lines, and the presence of Ca H and K, allowing
us to conclude that this a type-Ia supernova around maximum light
and very similar to SN 1994D (Patat et al. 1996, MNRAS 278, 111).
The expansion velocities, deduced from the absorption minima of Si
II 635.5-nm and Ca H and K, are 12~000 and 17~000 km/s
respectively. An unresolved absorption of Na I D is clearly
visible at the parent galaxy's rest-frame velocity (3257 km/s;
Mathewson and Ford 1996, Ap.J. Suppl. 107, 97), as in the case of
nearby SN 1998X. The measured total equivalent width of the Na I D
doublet is about 0.11 nm."
XTE J2123-058
C. Zurita and J. Casares, Instituto de Astrofisica de Canarias
(IAC), report: "CCD R-band images of the x-ray transient XTE
J2123-058 (IAUC 6955) have been obtained on Aug. 26 and 27 using
the 1-m Optical Ground Station telescope owned by the European
Space Agency and operated by the IAC at the Observatorio del Teide.
The object has declined to an average magnitude of R = 21.50 +/-
0.06 and the previously reported 1.4-mag orbital modulation has
completely disappeared (IAUC 6993). Instead, our data suggest the
dominance of the ellipsoidal modulation from the companion star: a
double-humped variability with a peak-to-peak amplitude of 0.20 +/-
0.16 mag. The current magnitude is consistent with pre-outburst
estimates (IAUC 6957, 6993), indicating that the transient has
probably reached quiescence. This represents the best opportunity
so far to detect the companion star spectroscopically."
COMET 9P/TEMPEL 1
P. Lamy, Laboratoire d'Astronomie Spatiale, and his team
report the detection of the nucleus of comet 9P with the Hubble
Space Telescope (+ WFPC2) on 1997 Dec. 31 at Delta = 3.53 AU and r
= 4.48 AU: "The slightly incomplete lightcurve indicates an
elongated body having semi-axes a = 3.9 and b = 2.8 km (assuming a
geometric albedo of 0.04) and a rotational period of about 25 hr.
No coma was detected."
(C) Copyright 1998 CBAT
1998 August 28 (7000) Daniel W. E. Green
Read IAUC 7001
.dvi or
.ps format.
Our Web policy. Index to the CBAT/MPC/ICQ pages.
