A Class G star is the third-dimmest type of main sequence star beside brown dwarfs. They are typically colored yellow or yellow-white. They made up roughly 8% of all main-sequence stars.
A typical Class G star has a mass of 0.9 (0.8 to 1.04) solar masses, a radius of 1.05 (0.96 to 1.15) solar radii, a luminosity of 1 (0.6 to 1.5) solar luminosity, a surface temperature of 5,600 K (5,200 K to 6,000 K), and a lifespan of 10,000,000,000 years on average. The core of Class G stars are usually at the range of 15,000,000°K (25,000,000°F).
Their habitable zones range from ~0.7 to 1.1 AU, and their long lifespans and relatively high brightness mean they are good candidates for life-bearing planets. Earth's sun is a class G star, actually, as are many stars with known extrasolar planets.
In the search for extraterrestial life, these stars, especially the less bright G stars (<G5V) have planets that are possible candidates for alien life. While they are good candidates, these stars are overlooked by K-class stars.
Life Cycle
- 0B yrs: Random protostar's gas forms a moderate-sized yellow star.
- 1B yrs: A newborn yellow dwarf star finally formed.
- 1.5B years: Star's planets, if any, finalized.
- 2B years: Star's system established.
- 5B years: Peak of well-being of star
- 6.5B years: Star is increasingly luminous.
- 9.5B years: Star Becomes an orange subgiant.
- 10B years: Star becomes a red giant.
- 10.5B years: Star explodes into a planetary nebula and leaves behind a white dwarf
- 11B years: Planetary nebula evaporates.
- 12B years: The white dwarf's peak in luminosity, before a slow cooldown.
- 15B years: White dwarf is considerably cooler, although it still has extremities.
Properties
Spectral type | Mass | Radius | Luminosity | Temperature (Fahrenheit) |
---|---|---|---|---|
G0V | 1.07 | 1.12 | 1.35 | 10,214 |
G1V | 1.03 | 1.06 | 1.20 | 10,088 |
G2V | 1.00 | 1.01 | 1.02 | 9,926 |
G3V | 0.99 | 0.994 | 0.98 | 9,836 |
G4V | 0.985 | 0.986 | 0.91 | 9,764 |
G5V | 0.98 | 0.982 | 0.89 | 9,728 |
G6V | 0.97 | 0.949 | 0.79 | 9,620 |
G7V | 0.95 | 0.939 | 0.74 | 9,530 |
G8V | 0.94 | 0.909 | 0.68 | 9,404 |
G9V | 0.9 | 0.876 | 0.55 | 9,224 |
See Also
Stellar Classes |
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