Central Bureau for Astronomical Telegrams
IAUC 3370: SS 433; 4U 1258-61
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Circular No. 3370
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
SS 433
P. Benvenuti, European Space Agency, reports: "SS 433 was observed
with the International Ultraviolet Explorer in the short-wavelength
range on May 30 at the European Ground Station and in
the long-wavelength range on June 5 by A. B. Underhill at NASA
Goddard Space Flight Center. Exposure times were 392 min and 395 min,
respectively. In both cases no spectrum was detected, setting an
upper limit to the mean ultraviolet flux of 0.5 x 10**-15 erg cm**-2
s**-1 A**-1 in the 1200-1900 A range and of 0.8 x 10**-15 erg cm**-2 s**-1
A**-1 in the 2000-3300 A range."
H. D. Aller, M. F. Aller, F. T. Haddock, P. E. Hodge and T. V.
Seling, University of Michigan; and J. G. Hills, Michigan State
University, report the detection of linear polarization from SS 433 at
8 GHz. On June 17d06h.5 the total flux density was 0.71 +/- 0.10 Jy.
The degree of polarization was 14.3 +/- 2.6 percent at a position
angle of 80o +/- 6o. On June 18 the polarized flux was comparable at
0.10 +/- 0.02 Jy.
4U 1258-61
G. E. Parkes, Mullard Space Science Laboratory; K. O. Mason,
Space Sciences Laboratory, University of California at Berkeley;
and P. G. Murdin, Royal Greenwich Observatory, report that
observations of the optical counterpart of the pulsating x-ray
source 4U 1258-61 (Mason et al. 1977, Monthly Notices Roy.
Astron. Soc. 184, 45P) on the Anglo-Australian Telescope in 1979
June show a marked change in the spectrum of the star compared to
1977 and 1978. Previous data had shown narrow shell lines superimposed
on the rotationally broadened spectrum of the underlying
star (spectral type B2V). H-alpha was in emission (equivalent width ~
12 A) with a narrow absorption core. The 1979 data show the H-alpha
line to be approximately a factor of 2 stronger than previously
observed, while the ratio of the red to violet components of the line
has increased. In addition, emission is now observed at H-alpha and the
strong He I lines. These indicators suggest that the mass-loss
rate from the star has increased substantially. This event provides
an interesting opportunity to study the behavior of the x-ray
source in a variable-mass-loss environment and hence better to
define the interaction of the x-ray-emitting object with the emission-line
star. Further x-ray and optical observations are urged.
1979 June 21 (3370) Daniel W. E. Green
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