Related papers: Modelling delta Scuti stars using asteroseismic sp…
Intermediate mass Pre-main sequence stars (1.5 $M_{\odot}< M < 5M_{\odot}$) cross the instability strip on their way to the main sequence. They are therefore expected to be pulsating in a similar way as the $\delta$ Scuti stars. In this…
The observational basis for asteroseismology is being dramatically strengthened, through more than two years of data from the CoRoT satellite, the flood of data coming from the Kepler mission and, in the slightly longer term, from dedicated…
delta Scuti stars are pulsating stars constituting the delta Scuti instability strip in the HR diagram, which consists of A and F stars of various evolutionary stages. They are in the transition region between high-mass hot stars and…
The evolutionary stage of the delta Scuti star 44 Tau has been unclear. Recent pulsation studies have claimed both main sequence and post-main sequence expansion models. A new photometric study increased the number of detected frequencies…
The delta Scuti star X Caeli has been the target of a simultaneous photometric (14 consecutive nights) and spectroscopic campaign (8 consecutive nigths). From the analysis of light curves we were able to pick up 17 frequency components,…
A study of the star KIC5892969 observed by the Kepler satellite is presented. Its three highest amplitude modes present a strong amplitude modulation. The aim of this work is to investigate amplitude variations in this star and their…
We find that the observed pressure-mode rotational splittings of slowly/moderately rotating Delta Scuti stars and Beta Cephei stars mostly have a positive asymmetry. That is, the left frequency spacing is larger than the right spacing in…
The recent asteroseismic data from the CoRoT and Kepler missions have provided an entirely new basis for investigating stellar properties. This has led to a rapid development in techniques for analysing such data, although it is probably…
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…
In Delta Scuti star models, the calculated amplitude ratios and phase differences for multi-colour photometry exhibit a strong dependence on convection. These observables are tools for determination of the spherical harmonic degree of the…
We construct seismic models of the four double-mode radial $\delta$ Scuti stars adopting opacities from three databases: OPAL, OP and OPLIB. The aim is to find the models that fit the observed frequencies of the two radial modes and have…
Delta Scuti ($\delta$ Sct) variables are intermediate mass stars that lie at the intersection of the main sequence and the instability strip on the Hertzsprung-Russel diagram. Various lines of evidence indicate that nonlinear mode…
We use TESS 10-minute Full Frame Images (Sectors 27-55) to study a sample of 1708 stars within 500 pc of the Sun that lie in a narrow colour range in the centre of the delta Scuti instability strip (0.29 < BP-RP < 0.31). Based on the…
Extensive photometric multisite campaigns of the Delta Scuti variable FG Vir are presented. For the years 2003 and 2004, 926 hours of photometry at the millimag precision level were obtained. The combinations with earlier campaigns lead to…
The Antartica Search for Transiting Extrasolar Planets (ASTEP), an automatized 400 mm telescope located at Concordia station in Antarctica, monitored beta Pictoris continuously to detect any variability linked to the transit of the Hill…
For $\delta$ Scuti star CoRoT 102749568, 52 independent frequencies were obtained by Papar$\acute{o}$ et al. 2013. We find that there are 4 multiplets and 8 doublets with nearly equal split caused by rotation. Differential rotation is…
The lower part of the classical instability strip and the surrounding main sequence are populated by a large variety of pulsating variable stars. In the past years a great effort was made by the stellar group of Brera Observatory to collect…
We used high-quality Kepler photometry and spectroscopic data to investigate the Kepler binary candidate KIC 5988140. Using the spectrum synthesis method, we derived the fundamental parameters Teff, log g, [M/H], and v.sini and the…
Recent observations of $\delta$ Scuti stars find evidence of nonlinear three-mode coupling in their oscillation spectra. There are two types of three-mode coupling likely to be important in $\delta$ Scuti stars: (i) direct coupling, in…
Context. Recently our ability to study stars using asteroseismic techniques has increased dramatically, largely through the use of space based photometric observations. Work has also been done using ground based spectroscopic observations…