I’ve always found red dwarf stars fascinating. With all the initial focus on the G class sun-like stars in the search for life, the long-lived and numerous red dwarfs seemed to have an enticing promise.
Most of them are too dim to be seen with the naked eye – adding to their mystery. It is estimated that 20 of the 30 closest stars to Earth are red dwarfs, yet no one of them can be seen without a telescope. The closest star to the sun is Proxima Centauri, a red dwarf 4.22 light-years from Earth. Through a telescope you can find it about four full-moon diameters away from Alpha and Beta Centauri, which appear as a single star in the night sky.
Compared to 10-billion-year expiry date suns like our own yellow G-class sun, red dwarfs can have lifetimes up to a trillion years. Am I the only one who is immediately imagining ancient civilisations glistening in the light of their red suns?
One way or another we will end up there anyway. Red dwarfs will outlive every other stellar cousin. If humanity survives that long, our star-faring descendants will have to migrate to nearby red dwarfs to stay in business as our sun fades to a white dwarf and then finally a black dwarf in a few billion years.
Any they do indeed have planets. In 2010 Gliese 581g was discovered around red dwarf Gliese 581 and dubbed the “first potentially habitable planet”. The fifth planet discovered in this system, it is thought to have a period of between 26-39 days and have a mass 2-3 times that of Earth. It’s orbit puts it somewhere similar to where Mercury orbits our sun, but with the lower intensity of the red dwarf, this should still allow liquid water. The Gliese 581 system is also tantalisingly close to Earth – around 20 lightyears away. So the Gliesians might be tuning in to watch 1993 TV on their satellite dishes as we speak.
One potential wrinkle for habitable planets around red dwarfs is the potential for tidally locked planets in close orbits to their suns. In this case, it is theorised that almost all the water would end up frozen on the cooler “dark side” on the planet. If you have enough water, then you would end up with a liquid water ‘ring’ along the temperate zone between the hot and cold sides. Because of the massive pressure of the ice sheets piling up on the cold side, you would get melting underneath, perhaps creating an ocean under the ice that would connect with the vast lakes around the terminator. How it all looks would depend on topography, the temperatures and exactly how much water you had. But somewhere in there would be zones suitable for life.
Anyone else got any fascinating red dwarf facts? Anyone set a story on a world orbiting a red dwarf?
I hope everyone is enjoying their free Calvanni ebook. Stay tuned for a free Scytheman (book 2).
Cross-posted at chrismcmahons blog.