Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 3333: mu Sgr; 1979 BA

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 3332 SEARCH Read IAUC 3334
IAUC number 

                                                  Circular No. 3333
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


mu SAGITTARII
     M. Plavec, Department of Astronomy, University of California
at Los Angeles, writes: "The star mu Sgr (HD 166937, V ~ 3.86, B8Ia)
has long been known to be a single-spectrum spectroscopic binary
with a period of 180.45 days.  Elvey (1938, Astrophys. J. 88, 110)
observed a shallow partial eclipse of the B8 supergiant, with a
duration of about 20 days and a maximum depth (in B) of ~ 0.14
magnitude.  In 1978, using the spectrographs aboard the satellites IUE
and Copernicus, R. S. Polidan and I detected a flux excess and some
spectral lines in the region 1000-1400 A, presumably due to a hotter
companion, of spectral type perhaps B0-3V.  An eclipse of this
companion was predicted for 1978 Sept. 11, and indeed Copernicus
scans on Sept. 12-14 showed a considerably reduced flux in the region
1000-1200 A.  Although the star has not been observed for many
years, the old ephemeris therefore appears to be good enough to
predict the next mid-eclipse of the companion for 1979 Mar. 10.  Since
this is the primary eclipse its depth in B may well be as much as
0.35 magnitude.  The duration of the eclipse may be ~ 20 days."


1979 BA
     Y. Kozai, Tokyo Astronomical Observatory, telexes the following
observation by E. Helin and K. Tomita at the Kiso Station:

     1979 UT          R. A. (1950) Decl.      Mag.
     Feb. 19.46767   10 33.9     +27 16       17

     This approximate position leads to a slight refinement (Incl. =
46o.2) of the elements on IAUC 3329 and the resulting ephemeris:

     1979 ET     R. A. (1950) Decl.     Delta     r     Mag.
     Mar.  8    10 10.80    +39 29.3    0.841   1.741   17.3
          13    10 04.85    +42 00.0
          18     9 59.90    +44 00.4    0.944   1.767   17.7
          23     9 56.12    +45 34.2
          28     9 53.63    +46 44.9    1.063   1.792   18.1
     Apr.  2     9 52.45    +47 36.2
           7     9 52.57    +48 11.5    1.191   1.818   18.4
          12     9 53.91    +48 33.3
          17     9 56.36    +48 43.9    1.322   1.843   18.7


1979 February 26               (3333)              Brian G. Marsden

Read IAUC 3332 SEARCH Read IAUC 3334

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

Valid HTML 4.01!