Outbursts on normal stars. FH Leo misclassified as a novalike variable
We present high resolution spectroscopy of the common proper motionsystem FH Leo (components HD 96273 andBD+07 2411B), which has been classified as a novalike variabledue to an outburst observed by Hipparcos, and we present and review theavailable photometry. We show from our spectra that neither star canpossibly be a cataclysmic variable, instead they are perfectly normallate-F and early-G stars. We measured their radial velocities andderived the atmospheric fundamental parameters, abundances of severalelements including Fe, Ni, Cr, Co, V, Sc, Ti, Ca and Mg, and we derivethe age of the system. From our analysis we conclude that the stars doindeed constitute a physical binary. However, the observed outburstcannot be readily explained. We examine several explanations, includingpollution with scattered light from Jupiter, binarity, microlensing,background supernovae, interaction with unseen companions and planetaryengulfment. While no explanation is fully satisfactory, the scatteredlight and star-planet interaction scenarios emerge as the least unlikelyones, and we give suggestions for further study.
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