Central Bureau for Astronomical Telegrams
IAUC 3517: SS 433; Cyg X-1
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 3518
Circular No. 3517
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
R. T. Schilizzi, Dwingeloo Radio Observatory; G. K. Miley,
Leiden Observatory; J. D. Romnay, Max-Planck-Institut fur
Radioastronomie; and R. E. Spencer, Jodrell Bank Observatory, report:
"VLBI observations at 60 mm using telescopes in Europe show
evidence of a change in the structure of SS 433 between Jan. 9 and
June 2. The telescopes involved were Effelsberg and Westerbork for
both epochs and Chilbolton (U.K.) in January and Knockin (Jodrell
Bank, U.K.) in June. The position angle defined by the maximum in
the fringe amplitudes on the Effelsberg-Westerbork baseline changed
from 98o +/- 3o on Jan. 9 to 114o +/- 3o on June 2. This can be compared
with the results of Walker et al. (1980, preprint), who found a
position angle in the range 87o-105o on 1979 May 12. These three
values appear consistent, within the errors, with the 164-165-day
period of the optical emission lines. There is evidence of
nonlinear jet-like structure in our June observations."
CYGNUS X-1
E. N. Walker, Royal Greenwich Observatory, reports that residuals
from a 7-year mean light curve in the B band show systematic
behavior. The pattern of residuals from observations 1980 June
29-July 8 is similar to that obtained 20-30 days after the 1975 Nov.
x-ray transition. The shape of the residual light curve is
reminiscent of eclipses of hot spots as seen in U-Gem-type stars.
Features in this residual light curve seem to move progressively
through the 5.6-day binary period. There is a suggestion of
significant changes over intervals as short as one day, and
complementary observations at other longitudes would be very valuable.
J. C. Kemp and M. S. Barbour, Physics Department, University
of Oregon, write: "Accompanying the 1980 June x-ray high state
(IAUC 3502), the UBV light curves showed a transient darkening of
up to 0.04 mag around orbital phase 0.25, lasting for a month or
more after x-ray turn-off. The second light maximum at phase 0.75,
however, stayed constant to within 0.015 mag throughout May-Sept.
The V-band polarization, as modulated on the orbital period, also
changed sharply: during June the amplitudes of the dominant second
harmonics of Q and U sensibly vanished; the amplitudes recovered in
July. Presumably the polarizing region had been obscured. New
analysis shows that the QU patterns have evolved dramatically over
past years."
1980 September 22 (3517) Brian G. Marsden
Read IAUC 3518
Our Web policy. Index to the CBAT/MPC/ICQ pages.
