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Hd 24975: A New Delta Scuti Star? (Or A Mild Ap Star with Short Photometric Variations?)

Published online by Cambridge University Press:  12 April 2016

C. Megessier
Affiliation:
Observatoire de Paris-Meudon F-92195 MEUDON, FRANCE
P. North
Affiliation:
Institut d’Astronomie de, l’Université de LausanneCH-1290 CHAVANNES-DES-BOIS, SWITZERLAND
M. Burnet
Affiliation:
Observatoire de Genève CH-1290 SAUVERNY, SWITZERLAND

Extract

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Looking in the literature for short period variations of Ap stars, we found the puzzling case of HD 24975. Used as a comparison star by Weiss (1978), it had been found then to present variations with a peak-to-peak amplitude of 0.01 in U, B and V with a period of about 45mn, but with no clear correlation between the three passbands.

HD 24975 has the same spectral type A2 as 21 Com which seems to present photometric variations with P ⋍ 31mn and Δ V < 0,02m (Percy, 1973, 1975). Both stars are near the blue edge of the δ Scuti instability strip in the HR diagram. The lack of photo metric data, however, prevented the precise location of HD 24975 from being found on the HR diagram.

Type
Section II - Systematics, Photometry
Copyright
Copyright © Reidel 1986

References

Breger, M.: 1979 Publ. Astron. Soc. Pacific 91, 5.CrossRefGoogle Scholar
Deeming, T.J.: 1975, Astrophys. Space Sci. 36, 137.CrossRefGoogle Scholar
Hauck, B.: 1985, Astron. Astrophys. (Submitted).Google Scholar
Percy, J.R.: 1973, Astron. Astrophys. 22, 381.Google Scholar
Percy, J.R.: 1975, Astron. J. 80, 698.CrossRefGoogle Scholar