Yellow Dwarfs: The Sun and Its Stellar Cousins

Yellow Dwarfs

Yellow dwarfs are G-type main-sequence stars, similar to the Sun. They have a mass between 0.8 and 1.2 solar masses, a radius similar to that of the Sun, and moderate luminosity. Their energy is mainly produced by the fusion of hydrogen into helium in the core.

Yellow dwarfs have the following characteristics:

• Mass: 0.8 to 1.2 M☉
• Radius: 0.9 to 1.2 R☉
• Effective temperature: 5,200 to 6,000 K
• Main sequence lifetime: about 10 billion years

The internal structure of a yellow dwarf includes several distinct zones:

• Core: where nuclear fusion reactions occur
• Radiative zone: where energy is transported by radiation
• Convective zone: where energy is transported by convection
• Photosphere: the visible surface of the star
• Chromosphere and corona: outer stellar atmospheres

Stellar Evolution

During their lifetime, yellow dwarfs go through several phases:

1. Main sequence: stable hydrogen fusion in the core.
2. Giant phase: when the central hydrogen is exhausted, the star expands and becomes a red giant.
3. Final phase: loss of outer layers and formation of a white dwarf.

The Most Studied Yellow Dwarfs

Sources: NASA – Stellar Data, International Astronomical Union.

Source: International Astronomical Union – Stellar Classification