The Shape of FK Comae

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Session 111 -- Stellar Interiors
Display presentation, Saturday, January 15, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[111.09] The Shape of FK Comae

Alan D.~Welty, Lawrence W.~Ramsey (Penn State)

FK Comae is an evolved G giant rotating at $v\sin i = 164.5 \pm 2.1\,$km$\,$s$^{-1}$ and exhibits a very strong H$\alpha$ emission line. In addition, it has long been known to have other signatures of magnetic activity characteristic of RS CVn systems and Weak-lined T Tauri stars such as $\Delta V \sim 0.1$ photometric variability indicative of spots, and strong X-ray and UV line emission. Our recent detailed analysis of the spectrum of this star have turned up variations in $v\sin i$ that we attribute to changes in the shape of the star of order 2.5\%. We present the data for several seasons to support this interpretation and discuss three possible explanations for this highly unusual observed behavior.

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