Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 3060: HDE 226868 (CYGNUS X-1); 1976e; 1976 AA

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 3059 SEARCH Read IAUC 3061
IAUC number 

                                                  Circular No. 3060
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


HDE 226868 (CYGNUS X-1)
     J. C. Kemp, Department of Physics, University of Oregon,
reports that observations (on 160 nights between Sept. 1974 and Mar.
1977) of the variable ultraviolet polarization of HDE 226868 reveal
a predominant period of 39.15 +/- 0.40 days, with a minimum on 1977
Feb. 25.6 UT.  The peak-to-peak amplitude of the polarization variation
is 0.40 percent, which is considerably larger than the coherent
variation on the normal 5.6-day orbital period.  The statistical
significance of the 39-day variation is over 99 percent.  It
should be noted that the predominant period as detected by other
means (e.g., radial velocities) might be 78 days, rather than 39.


PERIODIC COMET D'ARREST (1976e)
     The following precise positions have been reported:

     1976/77 UT          R. A. (1950) Decl.        m1    Observer
     July 29.28131    20 14 33.03   +10 40 03.0          Schwartz
     Aug. 19.80069    22 28 00.90   -23 06 38.8    7.3   Bruwer
          19.85278    22 28 22.01   -23 11 22.8            "
          26.93438    23 14 40.56   -31 54 15.8    6.5     "
          26.98091    23 14 56.29   -31 56 56.7            "
     Jan. 13.03256     2 17 28.30   - 7 30 11.3          Schwartz
          21.07445     2 27 20.07   - 5 23 06.5            "
          22.07065     2 28 34.40   - 5 07 47.8            "

G. Schwartz (Harvard Observatory).  Measurer: J. H. Bulger.
J. A. Bruwer (South African Astronomical Observatory Annexe,
   Hartbeespoort).  Franklin-Adams camera
H.-E. Schuster and O. Pizarro (European Southern Observatory).
   Measurer: Z. Sekanina.  A densitometer tracing shows a faint
   antitail extending about 2' west of the nucleus (cf. IAUC 2990).


1976 AA
     The following precise position was obtained by R. E. McCrosky
at Harvard Observatory's Agassiz Station.  Measurer: J. H. Bulger.

     1976 UT             R. A. (1950) Decl.
     Dec. 27.40731    11 38 09.78   + 6 46 55.5


1977 April 8                   (3060)              Brian G. Marsden

Read IAUC 3059 SEARCH Read IAUC 3061

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!