Central Bureau for Astronomical Telegrams
IAUC 3410: SS 433; mu Sgr; HR 8752
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Circular No. 3410
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
S. Baliunas, R. Noyes, W. Liller and S. Tokarz, Harvard-Smithsonian
Center for Astrophysics, report that the central intensity
of H-alpha relative to the continuum in SS 433 showed factor-of-two
increases on Apr. 29 and June 20, each lasting about two days.
Observations over five nights during these times, plus additional
observations on 14 other nights throughout the interval Apr. 28 to
June 24, showed all the data to be commensurate with the 13.1-day
period reported by Crampton et al. (IAUC 3388). Comparison with
other photometric data indicates that the ratio increases represent
increases of absolute H-alpha-emission-line intensity. The data were
obtained with the digital spectrograph at the Mount Hopkins 1.5-m
telescope.
mu SAGITTARII
J. D. Dorren, Biruni Observatory, Shiraz; and E. F. Guinan,
Villanova University, report that H-alpha photometric observations of mu
Sgr (B8Iap) that they have made at Villanova indicate that a hitherto
unobserved eclipse of the unseen companion of the B8 star began
around Sept. 10. Between Aug. 31 and Sept. 16 the decrease in
light was about 0.08 mag relative to the comparison star 15 Sgr.
Plavec (IAUC 3333, IBVS 1598) believes that the invisible component
may actually be the hotter star (B2?). An eclipse of the B8 star
lasting ~ 25 days was observed by Dorren at Biruni in H-alpha and u.
Mid-eclipse appeared to occur around June 10, the duration of minimum
light was ~ 11 days, and the depths were ~ 0.14 mag in H-alpha and
~ 0.16 mag in u.
HR 8752
J. R. Percy, University of Toronto, writes: "This star was
observed photometrically by D. Welch, using the Toronto 0.4-m
reflector, during the period when its spectrum was undergoing changes
(IAUC 3382, 3390 and 3399). The comparison stars were HR 8832 and
HR 8688, both of which were constant to +/- 0.01 mag. During June,
HR 8152 brightened by 0.1 mag in V, from 5.0 to 4.9. During July,
it remained approximately constant. During August, it brightened
by a further 0.1 mag in V, from 4.9 to 4.8.1
1979 September 27 (3410) Brian G. Marsden
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