Central Bureau for Astronomical Telegrams
IAUC 3173: Obs WITH THE IUE; NGC 4151; HR 1099 (= 4U 0336+01?); 1978b
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Read IAUC 3174
Circular No. 3173
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Cable Address: SATELLITES, NEWYORK Telex: 921428
Telephone: (617) 864-5758
OBSERVATIONS WITH THE INTERNATIONAL ULTRAVIOLET EXPLORER
A. Boggess, Goddard Space Flight Center; F. Macchetto, European
Space Agency; R. Wilson, University College, London, and Science
Research Council; and the IUE Science Commissioning Team report
that sample targets have been observed to determine the scientific
capabilities of the IUE, a geosynchronous satellite having a
45-cm telescope with ultraviolet spectrographs that was launched on
Jan. 26. Spectral coverage is from 1150 to 3200 A in two modes:
high dispersion with resolving power 10**4 and low dispersion with
resolution 6 A. Representative data have been obtained as follows:
Calibration stars. Preliminary sensitivity as a function of wavelength
has been determined by observing eta UMa in the high-dispersion
mode and HD 137389 at low dispersion.
Cool stars. A well-developed emission-line spectrum has been recorded
of alpha Aur in high dispersion, yielding the most extensive
chromospheric data available except for the sun. Emission lines
of H I 1216 A; O I 1302, 1304, 1306 A; C I 1657 A; C II 1334,
1336 A; He II 1640 A; Si III 1206, 1892 A; C III 1909 A; Si IV
1393, 1402 A; C IV 1548, 1550 A and N V 1240 A are notable in the
range 1150-2000 A. Mg II 2796, 2803 A dominate over 2000-3200 A.
Hot stars. Low-dispersion spectra of BD +75 325 show He II 1640 A
and a well-developed He II Paschen series. Preliminary identifications
of absorptions blueward include C IV 1550 A, N V 1240 A.
Extragalactic objects. Low-dispersion spectra of the Seyfert galaxy
NGC 4151 show emissions of L-alpha, C IV 1550 A, C III 1909 A and
possibly N V 1240 A, N IV 1488 A and Si III 1892 A. The 2200 A broad
absorption feature shows against a strong continuum above 2000 A.
X-ray stars. High-dispersion spectra were obtained of HD 153919
(4U 1700-37) on Feb. 12 near x-ray phase 0.36. Many well-developed
P-Cyg profiles are apparent, including C III 1176 A, C IV
1550 A and N V 1240 A, which are typical of an O6f star. Numerous
interstellar features are present in this highly reddened system.
Interstellar medium. Three excellent high-dispersion spectra of zeta
Oph show for the first time many very narrow interstellar absorption
lines in the region 1400-3000 A. Preliminary estimates of
the strength of lines occurring in the region 1200-1400 A are in
good agreement with those observed by the satellite Copernicus.
Solar system. A high-resolution (0.3 A) spectrum from 2000 to
3200 A shows several angstrom-wide, smooth absorption features in
the narrow-line solar spectrum reflected from the disk of Mars.
All correlative observations pertaining to these specific objects
are encouraged. Routine scheduled observing with the IUE satellite
is expected to begin on Apr. 3.
NGC 4151
A. F. Davidsen and G. F. Hartig report that the far-ultraviolet
(1150-1750 A) spectrum of the nuclear region of the Seyfert
galaxy NGC 4151 was observed with the rocket-borne faint-object
telescope launched from White Sands missile range on Feb. 10.2 UT.
An intense continuum, strong C IV emission and other probable features
have been observed. Because of the known variability of the
source interested observers at x-ray, optical, infrared and radio
wavelengths are invited to obtain timely flux measurements for use
in compiling an overall spectrum. Contact: Physics Department,
Attn. Ms. Garrigan, Johns Hopkins University, Charles and 34th
Streets, Baltimore, MD 21218, U.S.A.
HR 1099 (= 4U 0336+01?)
F. Walter, P. Charles and S. Bowyer, Space Sciences Laboratory,
University of California at Berkeley; and G. Garmire, California
Institute of Technology, using the HEAO-1 A-2 low-energy detectors,
have observed on 1977 Aug. 17 a weak source of soft x-rays with a
calculated peak flux of 2 x 10**-11 erg cm**-2 s**-1 near the position of
the transient x-ray source 4U 0336+01. They suggest that HR 1099,
a known radio source and one of the brightest RS CVn variables, is
the optical counterpart of the soft source and probably of the
transient also. The derived soft x-ray luminosity (0.15-2.8 keV)
is ~ 3 x 10**30 erg s**-1, within a factor of two of that observed from
the similar RS CVn system UX Ari. They also suggest that since alpha
Aur has been found to be an x-ray source and is also a long-period
RS CVn variable RS CVn systems are a new class of x-ray emitters.
PERIODIC COMET WILD 2 (1978b)
The following precise positions have been reported:
1978 UT R. A. (1950) Decl. m1 Observer
Jan. 31.52569 5 16 42.39 +20 06 12.9 Kurosaki
31.60653 5 16 40.84 +20 06 24.9 "
Feb. 1.52817 5 16 27.05 +20 08 39.2 "
1.59264 5 16 25.84 +20 08 49.7 "
2.53750 5 16 14.17 +20 11 08.2 13 Seki
2.54861 5 16 14.06 +20 11 09.5 "
2.78221 5 16 11.70 +20 11 45.4 13 Milet
4.75556 5 15 55.40 +20 16 48.3 14 Wild
4.77117 5 15 55.27 +20 16 48.5 "
T. Kurosaki (Utsunomiya) and T. Seki (Kochi Observatory, Geisei
Station). From Yamamoto Circ. No. 1876.
B. Milet (Nice Observatory). Comet diffuse with condensation.
P. Wild (Astronomical Institute, Berne University).
1978 February 17 (3173) Brian G. Marsden
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