| Responsible: INAF |
|---|
| Ennio Poretti |
The space mission CoRoT and Kepler observed hundreds of A-F type stars locate
inside the instability strip. Spectroscopic campaigns in the framework
of three ESO Large Programmes (LPs) were performed and some papers were published (see below).
They discuss in details the comparison between the models and the results from spectroscopic
mode identification. This task was very difficult due to the extreme complexity
of the pulsational content and a full comprehension of the rotational effects.
As a final output, the most powerful results were obtained on stars with a
clear frequency pattern only.
The HARPS spectra of A-F stars are now included in the spectroscopic
archive built in the context of the FP7-Space SpaceInn project. The spectra
are fully reduced in terms of careful determination of the physical parameters,
rotational velocities, and mean line-profiles. No extra work is foreseen on the
determination of these quantities. The goal of the SpaceInn archive is to make
the spectra available to the community for a deep analysis in function of
the spectral class and/or variability type. This is what we intend to perform in
the PERSIA project for A-F stars. Unexploited
spectra are available on HD 181555, HD 172189, HD 171834, HD 174532, HD 44195,
HD 170699, HD 43338, and HD 170133. The spectra of
HD 49434 (Uytterhoeven et al. 2008, A&A 489, 1213),
HD 50844 (Poretti et al. 2009, A&A 506, 85),
HD 174936 (Garcia Hernandez et al. 2009, A&A 506, 79),
HD 50870 (Mantegazza et al. 2012, A&A 542, A24),
HD 174966 (Garcia Hernandez et al. 2013, A&A 559, A63),
HD 51844 (Hareter et al. 2014, A&A 567, 124), and
HD 144277 (Zwintz et al. 2014, A&A 567, A4)
are also available for this kind of new analysis.
When developing the tools of a more detailed
comprehension of the rotational effects the INAF team will go back to the spectra and
compare predictions with observations in order to test we are going in the
right direction. These kind of tests will be performed by means of
codes supplied by other partners and existing software (e.g., FAMIAS). This will give us
back tighter constraints on the models, in a sort of virtuous circle.
Without the efforts programmed in the PERSIA project the pulsational
content of A-F stars will still remain not understood and this will have a
negative feedback in future missions, PLATO in particular. This should be
a frustrating insuccess for the asteroseismology technique, especially if
considering the large spectroscopic database available and the richness of
physical information contained in the line-profile variations.
For instance the age determination will remain limited to the lower part of the
Main Sequence, leaving the datation of the exoplanetary systems
around A-F stars an inaccurate technique.