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ON THE VARIABILITY OF VEGA
J. D. FERNIE
Publications of the Astronomical Society of the Pacific
Vol. 93, No. 553 (June 1981), pp. 333-337
Published by: Astronomical Society of the Pacific
Stable URL: http://www.jstor.org/stable/40677775
Page Count: 5
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Differential photometric observations of Vega with respect to ε¹ Lyr have been made on 14 nights spanning almost four months in 1980. All but three of these show constancy to within 0.006 mag. On two nights Vega was brighter than average by about 0.015 mag, and on one night by 0.041 ± 0.005 mag. No plausible explanation other than a real brightening of Vega can be found for these observations, although they do not seem to be pulsational in character. Simultaneous observations between ε¹ Lyr and ε² Lyr taken on all these nights, including the three unusual ones, show constancy to within 0.003 mag. The mass and radius of Vega match those of the δ Scuti star AI Vel, and a low-amplitude light and velocity variation of Vega observed by Guthnick (1931) is almost identical in shape and time scale to one observed for AI Vel. This and other evidence strongly suggest that on (rare?) occasions Vega shows low-amplitude variability of the δ Scuti type. UBVR1 data are presented for Vega, ε1 Lyr, ε² Lyr, and ζ¹ Lyr.
Publications of the Astronomical Society of the Pacific © 1981 The University of Chicago Press