Rotation and Oblateness of KIC11145123
Takashi Sekii (NAOJ), L. Gizon (MPS), M. Takata (University of Tokyo), D.W. Kurtz (University of Central Lancashire), et al.

KIC11145123 is a delta Scuti-gamma Doradus hybrid pulsator, whose pulsation frequencies have been measured by Kepler to very high precision (Kurtz et al 2014). The star rotates with a period of about 100 days, as indicated by rotational splitting frequencies. Unequal splittings in azimuthal multiplets inform us about differential rotation and structural asphericities. Here we report that the star is oblate, using multiplets in the p-mode frequency band. However, its measured oblateness is only about a third of what is expected from rotational oblateness alone. Guided by the results of helioseismology, we conjecture the presence of a magnetic field.