Class F — F-type (Yellow-White)

F-type stars are yellow-white stars with surface temperatures of 6,000 to 7,500 K. They make up about 3% of main-sequence stars. Their spectra show weakening hydrogen lines and strengthening calcium and iron lines compared to A-type stars. Notable examples include Canopus (F0II), the second-brightest star, and Procyon (F5IV-V). F-type stars are of great interest in the search for habitable exoplanets because their habitable zones are wider than those of cooler stars. They live for 2-4 billion years.

F-type stars bridge the gap between the hot A-types and the Sun-like G-types, with surface temperatures between 6,000 and 7,500 K. Comprising about 3% of main-sequence stars, they appear yellow-white and are of particular interest to exoplanet researchers because their habitable zones are wider than the Sun's while their lifetimes (2-7 billion years) are potentially long enough for complex life to evolve — though this remains a topic of active debate in astrobiology.

Characteristics

F-type spectra show weakening hydrogen lines and strengthening metal lines, particularly the ionized calcium H and K lines that become increasingly prominent toward later spectral types. F stars mark the transition where convective envelopes first appear, enabling magnetic activity and stellar cycles similar to the Sun's. The late-F stars (F5-F9) show measurable chromospheric activity and starspots. F stars have masses of 1.04-1.4 solar masses and luminosities of 1.5-5 times solar, making them easy targets for radial velocity exoplanet surveys.

Notable Examples

Procyon (Alpha Canis Minoris, F5IV-V) is the eighth-brightest star, a nearby F-type subgiant at 11.5 light-years with a white dwarf companion. Canopus (Alpha Carinae, F0Ib), the second-brightest star in the sky, is actually an F-type supergiant — enormously luminous at 10,700 solar luminosities. Polaris (Alpha Ursae Minoris, F7Ib) is an F-type supergiant and Cepheid variable, famous as the current North Star. The Cepheid period-luminosity relationship, crucial for measuring cosmic distances, was discovered using F and G-type Cepheid variables.

HIP 79736 HIP 79738 HIP 79742 HIP 79744 HIP 79746 HIP 32152 HIP 79760 HIP 79766 HIP 7977 HIP 7978 HIP 98277 HIP 9644 HIP 96440 HIP 9645 HIP 96450 HIP 96455 HIP 96458 HIP 79831 HIP 79832 HIP 79833 HIP 79835 HIP 79836 HIP 98301 HIP 98304 HIP 98307 HIP 79885 HIP 79886 HIP 79895 HIP 79896 HIP 9647 HIP 96473 HIP 96475 HIP 96476 HIP 99388 HIP 99392 HIP 99393 HIP 98330 HIP 98331 HIP 96511 HIP 96514 HIP 82106 HIP 89149 HIP 79954 HIP 79988 HIP 79991 HIP 79997 HIP 80007 HIP 80008

Frequently Asked Questions

What is a class F star?

Class F (F-type (Yellow-White)) stars are yellow-white stars. F-type stars are yellow-white stars with surface temperatures of 6,000 to 7,500 K. They make up about 3% of main-sequence stars. Their spectra show weakening hydrogen lines and strengthening calcium a

How hot are class F stars?

Class F stars have surface temperatures between 6,000 K and 7,500 K.

What color are class F stars?

Class F stars appear yellow-white.

How many class F stars are in the StarFYI database?

StarFYI currently catalogs 25,601 class F stars.

How luminous are class F stars?

Moderate, 1.5-5 solar luminosities

Class F — F-type (Yellow-White)

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Characteristics

Notable Examples

Frequently Asked Questions