Red dwarf superflares batter formerly 'habitable' exoplanet Humanity may have to rethink colonisation plans for exoplanet Kepler-438b, since what was hailed earlier this year as a candidate to support life as we know it, has now been declared decidedly inhospitable. The planet - a probably rocky world with a diameter 12 per cent bigger than Earth - was identified back in January, …
*points to Earth's mass extinctions*
Yeah, because a couple of solar flares will stop Life once it's gotten hold...
If the planet has an atmosphere that allows for liquid water, then there'll be oceans. Water tends to be pretty good at stopping "excess radiation", so any life in it has a double buffer when it comes to that. In fact, life here started there, and thrived, when land-based conditions here on Earth were decidedly hostile to life in general.
It all depends what you mean by "primitive" life, of course... Biologically speaking there's only "more" and "less" adapted to a particular environment. In that respect, most, if not all life on earth runs on the latest updates, and is still trying out the alpha builds.
Near a red dwarf the solar flares are a *lot* worse. Because the core is fully convective on the smaller red dwarves this leads to extremely large solar flares, magnitudes bigger than our sun produces.
However, this is not news I was taught this in an astrophysics course nearly thirty years ago.
> ... an atmosphere that allows for liquid water ...
No atmosphere necessary for that, except possibly a bit of water vapour.
I've always been amused that liquid water has been the only stated proxy for the "Goldilocks Zone", when so much more is required. Unless of course you aren't a carbon-based life form.
It all depends on whether or not that planet still has a functioning magnetic field.
Never mind solar flares, the Earth has copped plenty of those in its history, and we still have a functioning atmosphere. If the data from our solar system is any indication, your basic solar wind is much more significant in terms of atmoshere stripping than any solar flare activity. Even Pluto shows the effect, and you can't really say its particularly close to the Sun....
Besides.. that star being a red dwarf, 6 billion years would be rather youthful.. they last a wee bit longer than our Sun...
"scientists put the kibosh on the prospect of colonisation by noting that the Kepler-452 solar system's extreme age - six billion years"
Is that really considered extreme age for a G-class star? Ours is about 4.5 billion years old and considered middle-aged with a few billion years left before it uses up it's hydrogen. Kepler-452 sounds like it's in it's 50's - getting on a bit but still kicking.
Assuming we could get there and colonise the planet we could get at least a few hundred million years out of it surely?
Because of the sensitivity of the nuclear fusion rate to temperature and that owing to convection nearly all the hydrogen will be converted to helium (as opposed to our star), I've seen calculations that give a lifetime of 15 *trillion* years for some red dwarves. Yup, that's a thousand times longer than the current age of the universe. You would have enough time on this planet before it's sun faded to cold. The radiation from the star, well that's another matter.
"I've seen calculations that give a lifetime of 15 *trillion* years for some red dwarves"
That's very true, but only valid for smaller red dwarves. Kepler-438 is supposedly about 0.5 solar masses, so while it'll last longer than our own sun, it will in all likelihood end main sequence and become an intermediate red giant in a few billion years.
Given that Kepler-438b has such a close orbit, once that happens I think it would be fair to describe conditions on the surface of the exoplanet as 'a bit toasty'...
No one actually knows what happens to red dwarfs in their old age because the universe isn't nearly old enough yet for any to have aged sufficiently. The last time I read about this it was hypothesised that due to their complete internal convection, unlike our own Sun, as they run out of hydrogen to fuse they will shrink and become hotter and bluer in order to maintain equilibrium. Whether they would then enter in some sort of mini-red giant stage before turning into a mini-white dwarf, I don't know.
This is why the tri-annual solar surfing championship will be held there. Assuming there are enough contestants after the little accident with a neutron bomb caused the star to go supernova at the event a couple of years ago, wiping out the entire committee and all the contestants. Tri-D viewing figures went through the roof for that one...
Giant Mutated Cockroaches on Kepler whateveryMars! Which you can then fight under heavy personal sacrifice.
This takes "pulp fiction" to the limit, I guess.
In July, NASA declared it had discovered "the closest thing yet to another Earth" - Kepler-452b. Once again, scientists put the kibosh on the prospect of colonisation by noting that the Kepler-452 solar system's extreme age - six billion years - meant the planet is probably suffering as its venerable G-type star increases its energy output en route to expanding into a red giant.It's far more likely any inhabitants of Kepler-452b would be looking to colonise a small blue planet around a fairly young main sequence star, than the other way around.
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