Short answers, pulled from the story.
A G-type main-sequence star is a main-sequence star of spectral type G that fuses hydrogen into helium in its core, carrying roughly 0.9 to 1.1 solar masses. The Sun, classified specifically as a G2V star, is the best known example.
The term yellow dwarf is a misnomer, since G-type stars actually range in color from white in more luminous examples like the Sun to only a faint yellow tinge in less massive ones. The Sun looks yellow, orange, or red from Earth's surface because of atmospheric Rayleigh scattering, especially at sunrise and sunset.
A G-type main-sequence star with the Sun's mass fuses hydrogen for roughly 10 billion years before the core's hydrogen is exhausted. The class as a whole can remain stable long enough to support habitability for between 7.9 and 13 billion years.
Its core collapses and heats up, triggering shell fusion that expands the star through the subgiant branch and into the red giant phase about 1 billion years after leaving the main sequence. It then passes through a helium flash onto the horizontal branch, expands again on the asymptotic giant branch, sheds its outer layers as a planetary nebula, and leaves behind a cooling white dwarf.
Chara, the Sun, Kappa1 Ceti, and 61 Ursae Majoris anchor the G0V, G2V, G5V, and G8V classes and have remained unchanged as standards for years. HD 115043, 16 Cygni B, 70 Virginis, and 82 Eridani serve as other primary standards, though no G7V or G9V standard is yet agreed upon.
61 Virginis, HD 102365, HD 147513, 47 Ursae Majoris (also known as Chalawan), and Mu Arae (also known as Cervantes) are among the nearest G-type stars known to host planets. Tau Ceti was once reported to host up to eight planets, but a 2025 study using ESPRESSO data failed to unambiguously detect any.