An effective temperature calibration for main-sequence B- to F-type stars using VJHK_s colors

The effective temperature is an important parameter that is needed for numerous astrophysical studies, in particular to place stars in the Hertzsprung-Russell diagram, for example. Although the availability of large spectroscopic surveys increased significantly in the last decade, photometric data are still much more frequent. Homogeneous photometric (all-sky) surveys provide the basis to derive the effective temperature with reasonable accuracy also for objects that are not covered by spectroscopic surveys, or are out of range for the current spectroscopic instrumentations because of too faint magnitudes. We use data of the Two Micron All Sky Survey (2MASS) and broadband visual photometric measurements to derive effective temperature calibrations for the intrinsic colors (V-J), (V-H), (V-K_s), and (J-K_s), valid for B2 to F9 stars. The effective temperature calibrations are tied to the Strömgren-Crawford uvbyβ photometric system and do not depend on metallicity or rotational velocity.