Central Bureau for Astronomical Telegrams
IAUC 3712: CW 1103+254; V4024 Sgr = MWC 311
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Read IAUC 3713
Circular No. 3712
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
CW 1103+254
J. Bailey and D. A. Hanes, Anglo-Australian Observatory; and
D. J. Watts, A. B. Giles and J. G. Greenhill, University of Tasmania,
report: "Observations of this AM-Her-type variable (IAUC 3696)
obtained with the Anglo-Australian telescope show large variations
in the amplitude of its light curve. The magnitude range in white
light was 1.0 mag on June 8, 1.8 mag on June 9 and 1.5 mag on June
10. The near-infrared light curves were similar to the optical,
with J ranging from 13.5 to 14.5 and H from 13.0 to 14.0. Circular
polarization during the bright phase was -16 percent in the optical
and -7 percent at J. During spectroscopic observations on June 13
and 19, the star remained faint throughout the cycle. Very strong
emission lines of H, He I and He II were present. The line profiles
show two components with sinusoidal radial velocity curves
which cross at the beginning and end of the photometric bright
phase. The component with greatest redshift during the bright
phase has K = 600 km/s. The other has K = 300 km/s. The data are
consistent with two accretion streams onto opposite poles of a magnetic
white dwarf."
V4024 SAGITTARII = MWC 311
P. K. Barker, Department of Astronomy, University of Western
Ontario, telexes that he and E. R. Anderson have made
intensifier-dissector-scanner observations (resolving power 6000) of increasing
Balmer emission in the B2V-emission-line star V4024 Sgr (= MWC 311
= HR 7249 = HD 178175). On 1981 Oct. 3, H-alpha was observed to be weakly
in absorption, with the total width approaching 1000 km/s in the
wings. A narrow absorption core (possible shell spectrum?) had central
intensity 0.75. On 1982 June 24 and July 2, the continuum
across H-alpha was flat except for a weak emission feature of width 400
km/s; two emission peaks at intensity 1.2, separated by 200 km/s,
result from a very weak central reversal. Photographic spectra obtained
by Barker at the Sorriners-Bausch Observatory, University of
Colorado, show H-alpha in emission at roughly twice the continuum intensity
during 1975 Apr. and July and 1978 June. During 1975 H-beta absorption
showed no contamination by emission, but a sharp central
emission component of intensity 1.0 had developed by 1978. Participants
in the International Photometric and Spectroscopic Be-Star Observing
Campaigns are encouraged to monitor the object this season.
1982 July 19 (3712) Daniel W. E. Green
Read IAUC 3713
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