In Search of a Super-Bright, Super-Stable Star
Long ago, I asked a question on how to make possible turning the nine realms of Norse mythology--Midgard, Asgard, Vanaheimr, Jotunheimr, Alfheimr, Hel, Nidavellir, Niflheim and Museplheim--into nine actual worlds habitable enough for life to form. In staying true to the original mythology, these nine worlds orbit a trinary star system properly named "Odin", "Vili" and "Ve". Originally, they were going to be K-type main-sequence stars, or "orange dwarves". Astronomers searching for extraterrestrial life are always excited about orange dwarves for the following reasons:
- They live longer lifespans than G-type main-sequence stars ("yellow dwarves") like our sun--20 to 70 billion years, as opposed to our sun's mere 10 billion.
- They emit a limited quantity of ultraviolet radiation, which is a big enough problem from yellow dwarves but even worse from red dwarves, as UV radiation can damage DNA and thus hamper the emergence of nucleic acid based life.
At first, Odin, Vili and Ve were going to be orange dwarves, but I was presented with a problem--combined, the three have enough of a luminosity to create a habitable zone roughly 0.6 AUs wide--in translation, 55,800,000 miles, waaaaay too tight to fit nine Earth-like planets at once.
So in place of an orange dwarf, I am looking for a different type of star for the three brothers to be, one that would have the two listed benefits of orange dwarves but with additional features of a higher mass (1.2-12 solar masses, for example) and a higher luminosity (for example, enough for one to create a habitable zone, say, 150 million miles wide, roughly). Would such a star exist?
This post was sourced from https://worldbuilding.stackexchange.com/q/151117. It is licensed under CC BY-SA 4.0.
1 answer
The spectrum of a main-sequence star results mainly from the surface temperature, which is controlled by the star's mass. As mass increases, the star burns hotter, and as temperature increases, more of the stellar output is in higher wavelengths such as UV.
The lifespan of these stars also results from mass. With the mass increase, and thus the hotter burning core, the star expends hydrogen more quickly.
So, the answer to your question is: No. The lifespan and friendlier radiative output of K-class orange dwarfs is a result of their low mass. Increasing the mass of your stars will directly change these properties.
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