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arXiv · 1509.06943

Kepler observations of A-F pre-main sequence stars in Upper Scorpius: Discovery of six new $\delta$~Scuti and one $\gamma$~Doradus stars

V. Ripepi·L. Balona·G. Catanzaro·M. Marconi·F. Palla·M. Giarrusso
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Abstract

We present light curves and periodograms for 27 stars in the young Upper Scorpius association (age=$11 \pm 1$\,Myr) obtained with the Kepler spacecraft. This association is only the second stellar grouping to host several pulsating pre-main sequence (PMS) stars which have been observed from space. From an analysis of the periodograms, we identify six $\delta$~Scuti variables and one $\gamma$~Doradus star. These are most likely PMS stars or else very close to the zero-age main sequence. Four of the $\delta$~Scuti variables were observed in short-cadence mode, which allows us to resolve the entire frequency spectrum. For these four stars, we are able to infer some qualitative information concerning their ages. For the remaining two $\delta$~Scuti stars, only long-cadence data are available, which means that some of the frequencies are likely to be aliases. One of the stars appears to be a rotational variable in a hierarchical triple system. This is a particularly important object, as it allows the possibility of an accurate mass determination when radial velocity observations become available. We also report on new high-resolution echelle spectra obtained for some of the stars of our sample.

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V. Ripepi, L. Balona, G. Catanzaro, M. Marconi, F. Palla, M. Giarrusso. 2015-09-23. Kepler observations of A-F pre-main sequence stars in Upper Scorpius: Discovery of six new $\delta$~Scuti and one $\gamma$~Doradus stars. https://doi.org/10.1093/mnras%2Fstv2221

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