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We present a seismic study of $delta$ Scuti based on a mode identification from multicoulor photometry. The dominant frequency can be associated only with a radial mode and the second frequency is, most probably, a dipole mode. The other six frequencies have more ambiguous identifications. The photometric mode identification provided also some constraints on the atmospheric metallicity [m/H]$approx$+0.5 and microturbulent velocity $xi_tapprox 4~kms$. For models reproducing the dominant frequency, we show that only the fundamental mode is possible and the first overtone is excluded. However, the location of $delta$ Scuti near the terminal age main sequence requires the consideration of three stages of stellar evolution. For the star to be on the main sequence, it is necessary to include overshooting from the convective core with a parameter of at least $alpha_{rm ov}=0.25$ at the metallicity greater than $Z=0.019$. It turned out that the value of the relative amplitude of the bolometric flux variations (the nonadiabatic parameter $f$) is mainly determined by the position of the star in the HR diagram, i.e., by its effective temperature and luminosity, whereas the effect of the evolutionary stage is minor. On the other hand, the convective efficiency in the subphotospheric layers has a dominant effect on the value of the parameter $f$. %in the $delta$ Sct star models. Comparing the theoretical and empirical values of $f$ for the radial dominant mode, we obtain constraints on the mixing length parameter $alpha_{rm MLT}$ which is less than about 1.0, independently of the adopted opacity data and chemical mixture. This value of $alpha_{rm MLT}$ is substantially smaller than for a calibrated solar model indicating rather low to moderately efficient convection in the envelope of $delta$ Scuti.
High-resolution spectroscopy is a powerful tool to study the dynamical structure of pulsating stars atmosphere. We aim at comparing the line asymmetry and velocity of the two delta Sct stars rho Pup and DX Cet with previous spectroscopic data obtaine
We report on a multi-site photometric campaign on the high-amplitude $delta$ Scuti star V2367 Cyg in order to determine the pulsation modes. We also used high-dispersion spectroscopy to estimate the stellar parameters and projected rotational velocit
As part of the NASA Kepler Guest Observer program, we requested and obtained long-cadence data on about 2700 faint (magnitude 14-16) Kepler stars with effective temperatures and surface gravities that lie near or within the pulsation instability regi
We identify the RR Lyrae and delta Scuti (DSCT) stars in three catalogs of GALEX variable sources. The NUV amplitude of RR Lyrae stars is about twice that in V-band, so we find a larger percentage of low amplitude variables than catalogs such as Abba
Inspired by the so appealing example of red giants, where going from a handful of stars to thousands revealed the structure of the eigenspectrum, we inspected a large homogeneous set of around 1860 {delta} Scuti stars observed with CoRoT. This unique