| TESS observations of Cepheid and RR Lyrae stars: first results |
| Emese Plachy |
| Konkoly Observatory |
| Space-based photometry has revealed new, important details about RR Lyrae and Cepheid stars. With TESS, we are able to sample a large collection of Cepheids, although the mission only provides us with snapshots, due to their long pulsation periods. The Magellanic Clouds include many interesting targets, but blending and contamination is hindering the data quality. Nevertheless the combination of multiple sectors can produce valuable data sets for bright Cepheids. TESS will also be transformative for the rare and less understood anomalous Cepheid class. We discovered the first sign of nonradial modes in one of their prototypes, the overtone star XZ Cet. The mode seems to be the exact analogue of the family of additional modes observed in many overtone RR Lyrae and classical Cepheid stars, indicating a common origin. TESS is also observing the nearby population of RR Lyrae stars. We identified low-amplitude additional modes in a large fraction of them, and we noticed differences in the distribution of these additional modes compared to the Bulge RR Lyrae population. |