We present yb time–series CCD photometry of the high–amplitude δ Scuti star V 1162 Ori. A period break and a significant decrease in amplitude (50 percent) has been reported for this star by Hintz et al. (1998). New observations carried out over two observing seasons suggest that the period found by Hintz et al. (1998) was no longer valid in early 1998, and that the period again changed during ...

We present a comprehensive asteroseismic study of the double-mode high-amplitude δ Scuti star HD 187642 (RV Ari). The modelling includes some of the most recent techniques: 1) effects of rotation on both equilibrium models and adiabatic oscillation spectrum, 2) non-adiabatic study of radial and non-radial modes, 3) relationship between the fundamental radial mode and the first overtone in the f...

We present a classification of 39 new variable stars with spectral type between A2 and F8 discovered by Hipparcos with the aim to find new γ Doradus stars. We have used a multivariate classification scheme and report the discovery of 14 new γ Doradus variables among this unbiased sample. Our results point out the biased nature towards hot temperatures of earlier, ground-based surveys of these v...

In this paper we revise and complete the photometric survey of the instability strip of the southern open cluster NGC 2516 published by Antonello and Mantegazza (1986). No variable stars with amplitudes larger than 0 m .02 were found. However by means of an accurate analysis based on a new statistical method two groups of small amplitude variables have been disentangled: one with periods < 0 d ...

Using a vector vortex coronagraph behind the 1.5-m well-corrected subaperture (WCS) at Palomar, we detected a second object very close to ǫ Cephei, a δ Scuti F0 IV star. The candidate companion, ∼ 50 times fainter than ǫ Cephei, if physically associated, is a late-type K or early M star, and lies at an angular separation of 330 mas, or 1.1 λ/D for the WCS, making it the smallest angle detection...