K5V

K5V is a stellar classification indicating a K-type star (cooler and redder than the Sun) with a luminosity class V, meaning it is a main-sequence star that fuses hydrogen in its core. The designation places the star in the middle of the cooler end of the spectral sequence, with subclass 5 within the K-type range.

Typical properties of a K5V star include an effective surface temperature around 4,400 kelvin, a radius of roughly 0.7 times that of the Sun, and a mass about 0.6–0.7 solar masses. Its luminosity is relatively low, on the order of 0.1–0.2 solar luminosities, giving it an orange to orange-red appearance. Because of the lower temperature and brightness, K5V stars are fainter than the Sun and most other visible stars, but they are common in the solar neighborhood.

In stellar spectra, K-type stars show prominent metal lines and relatively weak hydrogen lines, with molecular features such as titanium oxide present but less dominant than in cooler M-dwarfs. The MK system assigns the V luminosity class to main-sequence stars, which are in stable hydrogen-burning phases and have lifetimes spanning many billions of years.

K5V stars are long-lived and numerous in the galaxy, making them important for studies of stellar populations and exoplanets. Their habitable zones lie closer to the star than Earth’s orbit due to lower luminosity, typically around a fraction of an astronomical unit to around 1 AU, depending on atmospheric models. These stars are among the favored targets for planet-hunting campaigns because they offer a stable, long-lasting energy output and favorable conditions for detecting planets.