F star

Properties of typical F-type main-sequence stars.

Properties of typical F-type main-sequence stars.

An F star, or F-type star, is a white or yellowish-white star of spectral type F whose spectrum shows strong absorption lines of ionized calcium which are more prominent than the hydrogen lines. Moderately strong lines due to iron and other heavier elements are also in evidence.


Main sequence F stars, of which Procyon is an example, have a surface temperature of 6,050 to 7,220 K, a mass of 1.1 to 1.6 solar masses, and a luminosity of 2 to 7 times that of the Sun. Relatively nearby, late-type members of this category are generally included in the list of target stars for exoplanet searches and targeted SETI programs.


F-type supergiants, of which Canopus and Polaris (the Pole Star) are examples, have a mass up to 12 solar masses and a luminosity up to 32,000 times that of the Sun.


Fp star

An Fp star is an F star whose spectrum reveals unusual chemical abundances of some metals. Fp stars are essentially an extension of Ap stars to cooler temperatures and spectral type F2, and include the group known as chromium-europium-strontium stars.