Near infrared light variations of CP stars^*

The SiSrCrEu stars

¹ Istituto di Astronomia, Città Universitaria, Viale A, Doria 6, I–95125 Catania, Italy
² C.N.R.-G.N.A, Unità di ricerca di Catania, Città Universitaria, Viale A, Doria 6, I–95125 Catania, Italy
³ Osservatorio Astrofisico di Catania, Città Universitaria, Viale A, Doria 6, I–95125 Catania, Italy
⁴ Instituto de Astrofisica de Canarias, 38200 La Laguna, Tenerife, Spain

Send offprint request to: F.A. Catalano

Received: 17 November 1997
Accepted: 4 February 1998

Abstract

Twelve magnetic Chemically Peculiar (CP2) stars of the SiSrCrEu subgroup mostly brighter than the 7.5 visual magnitude have been investigated in the infrared at 1.25, 1.6 and 2.2 μ. The stars HD 74521, HD 90044, HD 119419, HD 125630, and HD 187473 are clearly variable in the near infrared with the same period as the visible light, spectrum, and magnetic field variations. The stars HD 10783, HD 12447, HD 116458, HD 147010, HD 166469, HD 170397, and HD 223640 do show a smaller amount of variability, although with quite large a dispersion of the data. A remarkable result of the present investigation is that, at least for the stars for which contemporaneous observations are available, the observed infrared variations appear to be in phase with the variations in the long wavelength part of the visible. This may be an indication that the mechanism of the infrared variations should be the same as for the visible.