The MESAS Project: ALMA Observations of the F-type Stars γ Lep, γ Vir A, and γ Vir B

The spectrum of stars in the submillimeter to centimeter wavelength range remains poorly constrained due to a lack of data for most spectral types. An accurate characterization of stellar emission in this regime is needed to test stellar atmosphere models, and is also essential for revealing emission associated with unresolved circumstellar debris. We present Atacama Large Millimeter/submillimeter Array observations of the three nearby, main-sequence, debris-poor, F-type stars γ Lep, γ Vir A, and γ Vir B at 0.87 and 1.29 mm. We use these data to constrain semiempirical atmospheric models. We discuss the atmospheric structure of these stars, explore potential short-term variability, and the potential impact on debris disk studies. These results are part of an ongoing campaign to obtain long wavelength observations of debris-poor stars, entitled Measuring the Emission of Stellar Atmospheres at Submillimeter/millimeter wavelengths.