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Rapidly oscillating Ap stars observed with TESS. The LAMOST Ap sample and 49 Cam
Inês Rolo, Daniel L. Holdsworth, Margarida S. Cunha +4
The rapidly oscillating chemically peculiar A-type (roAp) stars offer valuable insights into the internal physical processes of all stars, but their study is challenged by their ra…
On the seismic modelling of subgiant stars: testing different grid interpolation methods
Miguel Clara, Margarida S. Cunha, Pedro P. Avelino +3
Context. The emergence of mixed modes during the subgiant phase, whose frequencies are characterized by a fast evolution with age, can potentially enable a precise determination of…
Evolution of Dipolar Mixed-mode Coupling Factor in Red Giant Stars: Impact of Buoyancy Spike
Chen Jiang, Margarida Cunha, Joergen Christensen-Dalsgaard +2
Mixed modes observed in red giants allow for investigation of the stellar interior structures. One important feature in these structures is the buoyancy spike caused by the discont…
Analytical modelling of period spacings across the HR diagram
M. S. Cunha, P. P. Avelino, J. Christensen-Dalsgaard +4
The characterisation of stellar cores may be accomplished through the modelling of asteroseismic data from stars exhibiting either gravity-mode or mixed-mode pulsations, potentiall…
Seismic signatures of magnetic activity in solar-type stars observed by Kepler
A. R. G. Santos, T. L. Campante, W. J. Chaplin +8
The properties of the acoustic modes are sensitive to magnetic activity. The unprecedented long-term Kepler photometry, thus, allows stellar magnetic cycles to be studied through a…
PLATO as it is: a legacy mission for Galactic archaeology
A. Miglio, C. Chiappini, B. Mosser +102
Deciphering the assembly history of the Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps of the Galaxy.…
On the relation between activity-related frequency shifts and the sunspot distribution over the solar cycle 23
A. R. G. Santos, M. S. Cunha, P. P. Avelino +2
The activity-related variations in the solar acoustic frequencies have been known for 30 years. However, the importance of the different contributions is still not well established…
Learning about the latitudinal distribution of starspots through the periodogram analysis of photometric data
A. R. G. Santos, M. S. Cunha, P. P. Avelino +2
Starspots are cooler and darker than the stellar surface. Therefore, the emitted flux of a star changes when spots are visible on its surface. The presence of spots together with t…
Starspot signature on the light curve: Learning about the latitudinal distribution of spots
A. R. G. Santos, M. S. Cunha, P. P. Avelino +2
Quasi-periodic modulations of the stellar light curve may result from dark spots crossing the visible stellar disc. Due to differential rotation, spots at different latitudes gener…
Spot cycle reconstruction: an empirical tool - Application to the sunspot cycle
A. R. G. Santos, M. S. Cunha, P. P. Avelino +1
The increasing interest in understanding stellar magnetic activity cycles is a strong motivation for the development of parameterized starspot models which can be constrained obser…
Inferring properties of small convective cores in main-sequence solar-like pulsators
I. M. Brandão, M. S. Cunha, J Christensen-Dalsgaard
This work concerns the study of the properties of convective cores in main-sequence models of solar-like pulsators and what information they may hold about stellar ages. We verifie…
The fundamental parameters of the roAp star 10 Aql
K. Perraut, S. Borgniet, M. Cunha +12
Due to the strong magnetic field and related abnormal surface layers existing in rapidly oscillating Ap stars, systematic errors are likely to be present when determining their eff…
Discovery of new roAp pulsators in the UVES survey of cool magnetic Ap stars
O. Kochukhov, D. Alentiev, T. Ryabchikova +4
We have carried out a survey of short-period pulsations among a sample of carefully chosen cool Ap stars using time-resolved observations with the UVES spectrometer at the ESO 8-m…
Discovery of the longest-period rapidly oscillating Ap star HD177765
D. Alentiev, O. Kochukhov, T. Ryabchikova +3
We present the discovery of a long-period, rapidly oscillating Ap star, HD177765. Using high-resolution time-series observations obtained with UVES at the ESO VLT telescope, we fou…
On the understanding of pulsations in the atmosphere of roAp stars: phase diversity and false nodes
J. C. Sousa, M Cunha
Studies based on high-resolution spectroscopic data of rapidly oscillating Ap stars show a surprising diversity of pulsation behavior in the atmospheric layers, pointing, in partic…
Oscillations and magnetic fields in the G8 star EK Eridani
T. H. Dall, M. Cunha, K. G. Strassmeier +2
Asteroseismology can provide information that is otherwise not easily accessible, like the stellar mass and the evolutionary stage. Strong magnetic fields are usually accompanied b…