The Villanova alpha photometric system

Basic Reference

Baliunas S.E., Ciccone M.A., Guinan E.F. 1975, PASP 87, 969


Halpha and Hbeta photoelectric observations of 33 early-type standard stars and 23 Be stars were obtained at the Villanova University Observatory on 27 nights between January 1972 and February 1973. The data permit separation of the stronger-lined Be stars from the normal stars and reveal variations in the Be star gamma Cas. When compared with earlier data obtained by other, the Villanova data show longer-term variations in five other Be stars as well: omega Ori, dzeta Tau, kappa Dra, 23 Tau, and psi Per.


Access to the data and references

Asiago Database on Photometric System (ADPS)

Indices and Parameters

alpha, beta


   Filter            wavelength   Width
                        [Å]        [Å]

   Halpha wide          6575       295
   Halpha narrow        6565        36
   Hbeta wide           4870        65
   Hbeta narrow         4863        25


EMI 9558 QB
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Last update: 21 May 1996