Central Bureau for Astronomical Telegrams
IAUC 5378: EF Peg; GX 1+4; N Sct 1991
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Read IAUC 5379
Circular No. 5378
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
EF PEGASI
J. DeYoung and R. Schmidt, U.S. Naval Observatory, communicate:
"With the 0.6-m reflector, 374 CCD images were made in the Kron-
Cousins I band between Oct. 18.988 and 27.047 UT, during which time
seven maxima were observed. A linear least-squares fit to these
observations and to the Kyoto report (IAUC 5371) yields the ephemeris
HJDmax = 2448547.954 (+/- 0.006) + 0.08696 (+/- 0.00008)E. The
period lies outside the period gap for cataclysmic variables. In the
I band, EF Peg continues to decline in brightness at 0.1 mag/day,
and the I superhump peak-to-peak amplitude has declined from 0.3 to
0.2 mag over the above interval; the maximum-minimum ratio is 0.3.
Secondary 'humps' of amplitude < 0.1 mag in I at phase 0.6 were
observed."
Visual magnitude estimates by P. Schmeer, Bischmisheim, Germany:
Oct. 22.74 UT, 11.7; 25.90, 12.2; 26.81, 12.4.
GX 1+4
R. Sunyaev, M. Gilfanov, D. Barret, and F. Lebrun, on behalf of
the GRANAT/SIGMA team (Space Research Institute, Moscow; Centre
d'Etude Spatiale des Rayonnements, Toulouse; Service d'Astrophysique
du CEA, Saclay), report: "During GRANAT observations of the Galactic
Center region on Oct. 17-18 and 18-19, the hard x-ray flux (40-
70 keV) of GX 1+4 was found significantly higher than during previous
observations of this source obtained during Aug. 30-Oct. 10.
The pulsation period (for the solar barycenter) was found to be
116.41 +/- 0.05 s, indicating further spin-down of the source
(Pdot/P = 0.02 yrE-1), with respect to previously reported GRANAT
observations in 1991 March and April (IAUC 5245)."
NOVA SCUTI 1991
C. E. Woodward, University of Wyoming; and M. A. Greenhouse,
National Air and Space Museum, Smithsonian Institution, write: "We
obtained infrared spectra of N Sct 1991 on Sept. 29.10 UT with the
Cerro Tololo Interamerican Observatory 1.5-m reflector (+ IRS
spectrometer). The Br-gamma H I emission line (2.166 microns) was
resolved with FWHM about 934 km/s and an observed flux of about 5.8 x
10E-17 erg cmE-2 sE-1. No [Si VII] coronal line emission at 2.474
microns was detected."
1991 October 30 (5378) Daniel W. E. Green
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