G-type star

astronomy

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June 29, 2026

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A G-type star, also known as a G star, is a type of star classified by its surface temperature. The Sun is a well-known example of a G-type star.1

G-type stars are yellow and have surface temperatures ranging from approximately 5,000 to 6,000 Kelvin (K). Their spectra are characterized by the presence of metallic lines, particularly those of iron, calcium, and sodium, as well as some stable molecular fragments like cyanogen (CN) and hydroxyl radical (OH).23

The spectral classification system, which includes G-type stars, orders stars from hottest to coolest using the letters O, B, A, F, G, K, and M. G-type stars fall in the middle of this sequence, indicating a moderate temperature compared to hotter O and B stars or cooler K and M stars.23

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Cepheid variable
…hot) at maximum luminosity and type G (cooler, Sun-like) at minimum. The prototype star is Delta Cephei, the variability of which was discovered by John Goodricke in 1784. In 1912 Henrietta Leavitt of Harvard Observatory discovered the aforementioned period-luminosity relationship of the Cepheids.
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…hot) at maximum luminosity and type G (cooler, Sun-like) at minimum. The prototype star is Delta Cephei, the variability of which was discovered by John Goodricke in 1784. In 1912 Henrietta Leavitt of Harvard Observatory discovered the aforementioned period-luminosity relationship of the Cepheids.
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star
Classification of spectral types
…these stars and even in G-type stars such as the Sun. The spectra of G-type stars are dominated by the characteristic lines of metals, particularly those of iron, calcium, sodium, magnesium, and titanium.
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…these stars and even in G-type stars such as the Sun. The spectra of G-type stars are dominated by the characteristic lines of metals, particularly those of iron, calcium, sodium, magnesium, and titanium.
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stellar classification
The Sun is a class G star; these are yellow, with surface temperatures of 5,000–6,000 K. Class K stars are yellow to orange, at about 3,500–5,000 K, and M stars are red, at about 3,000 K, with titanium oxide prominent in their spectra. L brown dwarfs have temperatures between…
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The Sun is a class G star; these are yellow, with surface temperatures of 5,000–6,000 K. Class K stars are yellow to orange, at about 3,500–5,000 K, and M stars are red, at about 3,000 K, with titanium oxide prominent in their spectra. L brown dwarfs have temperatures between…
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