of ionized metals (Fe II, Mg II, Si II) at a maximum at A5. The presence of Ca II lines is notably strengthening by this point. About 1 in 160 (0.625%) of the main-sequence stars in the solar neighborhood are A-type stars, which includes 9 stars within 15 parsecs. Spectral standards: A0Van – Gamma Ursae Majoris A0Va – Vega A0Ib – Eta Leonis A0Ia – HD 21389 A1V – Sirius A A2Ia – Deneb A3Va – Fomalhaut Class F F-type stars have strengthening spectral lines H and K of Ca II. Neutral metals (Fe I, Cr I) beginning to gain on ionized metal lines by late F. Their spectra are characterized by the weaker hydrogen lines and ionized metals. Their color is white. About 1 in 33 (3.03%) of the main-sequence stars in the solar neighborhood are F-type stars, including 12 stars within 10 pc. Spectral standards: F0IIIa – Zeta Leonis F0Ib – Alpha Leporis F2V – 78 Ursae Majoris Class G G-type stars, including the Sun, have prominent spectral lines H and K of Ca II, which are most pronounced at G2. They have even weaker hydrogen lines than F, but along with the ionized metals, they have neutral metals. There is a prominent spike in the G band of CN molecules. Class G main-sequence stars make up about 7.5%, nearly one in thirteen, of the main-sequence stars in the solar neighborhood. There are 21 G-type stars within 10pc. Class G contains the "Yellow Evolutionary Void". Supergiant stars often swing between O or B (blue) and K or M (red). While they do this, they do not stay for long in the unstable yellow supergiant class. Spectral standards: G0V – Beta Canum Venaticorum G0IV – Eta Boötis G0Ib – Beta Aquarii G2V – Sun G5V – Kappa1 Ceti G5IV – Mu Herculis G5Ib – 9 Pegasi G8V – 61 Ursae Majoris G8IV – Beta Aquilae G8IIIa – Kappa Geminorum G8IIIab – Epsilon Virginis G8Ib – Epsilon Geminorum Class K K-type stars are orangish stars that are slightly cooler than the Sun. They make up about 12% of the main-sequence stars in the solar neighborhood. There are also giant K-type stars, which range from hypergiants like RW Cephei, to giants and supergiants, such as Arcturus, whereas orange dwarfs, like Alpha Centauri B, are main-sequence stars. They have extremely weak hydrogen lines, if those are present at all, and mostly neutral