Central Bureau for Astronomical Telegrams
IAUC 6802: ECLIPSE OF LMC CLASSICAL CEPHEID; 1997ei; 69P
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Circular No. 6802
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)
ECLIPSE OF LMC CLASSICAL CEPHEID
D. Welch, Department of Physics and Astronomy, McMaster University,
communicates: "The MACHO collaboration (cf. IAUC 6312) has discovered
a 4.97-day-period classical cepheid in the Large Magellanic Cloud in an
eclipsing-binary system the next primary minimum of which will occur on
Feb. 25.0 (+/- 3) UT. The system is located at R.A. = 05h20m25s.1, Decl.
= -70d11'08" (equinox 2000.0), has an orbital period of 400 days and an
out-of-eclipse mean magnitude and color of V = 14.55, V-R = +0.07. The
V semiamplitude of the system outside eclipse is about 0.05 mag. The
radial-velocity semiamplitude of the cepheid or its companion is likely
about 30 km/s, making the system useful for a determination of dynamical
masses. Primary eclipse is between one and two weeks in total duration,
during which the system becomes as faint as V = 15.2 and R = 15.1.
It should be noted that the LMC will be progressively less well-placed
for observing during primary eclipses in the following five years."
Potential observers are requested to contact Welch at
welch@physics.mcmaster.ca, or by telephone at +1-905-525-9140 (extension
23186) to coordinate observations.
SUPERNOVA 1997ei IN NGC 3963
L. Wang, D. A. Howell and J. C. Wheeler, University of Texas,
report: "A spectrogram (range 420-813 nm; resolution about 1 nm)
of SN 1997ei was obtained with the 2.1-m telescope (+ IGP) at
McDonald Observatory on 1997 Dec. 29. Preliminary analysis shows that
the spectrum is similar to that of SN 1987M about one week past
maximum (Filippenko et al. 1990, A.J. 100, 1575) and SN 1994I close to
maximum. This suggests that SN 1997ei may be of type Ic, rather than
type Ia (IAUC 6796, 6800). The absorption features at 625 and 760 nm
can be identified with Si II 635.5 nm and O I 777.4 nm, respectively.
The O I 777.4-nm feature in SN 1997ei is stronger than the Si II 635.5-nm
feature. The O I 777.4-nm feature in SN 1997ei is also stronger
than the same feature in SNe 1994I and 1987M. Further observations
are needed to confirm the classification. Our spectrum is accessible
at http://tycho.as.utexas.edu/~lifan/Images/sn97ei.gif."
COMET 69P/TAYLOR
CCD magnitude estimates: 1997 Oct. 8.79 UT, 17.8 (A. Sugie, Dynic
Observatory, 0.60-m reflector); 12.84, 18.3 (M. Yamanishi et al., Saji
Observatory, 1.0-m reflector); Nov. 1.79, 17.9 (Sugie); 7.76, 17.6
(Yamanishi et al.); 9.78, 18.3 (A. Nakamura, Kuma, Ehime, Japan, 0.60-m
reflector); Dec. 4.77, 16.4 (Nakamura); 24.71, 15.1 (Nakamura).
(C) Copyright 1998 CBAT
1998 January 2 (6802) Brian G. Marsden
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