Kepler Confirms 100+ New Exoplanets (phys.org) 37
schwit1 writes: Astronomers have confirmed another 100 of Kepler's more than 3,000 candidate exoplanets. Phys.org reports: "One of the most interesting set of planets discovered in this study is a system of four potentially rocky planets, between 20 and 50 percent larger than Earth, orbiting a star less than half the size and with less light output than the Sun. Their orbital periods range from five-and-a-half to 24 days, and two of them may experience radiation levels from their star comparable to those on Earth. Despite their tight orbits -- closer than Mercury's orbit around the sun -- the possibility that life could arise on a planet around such a star cannot be ruled out, according to Crossfield." Because the host star as well as many of these other confirmed exoplanets are red dwarf stars, the possibility of life is reduced because the star and its system is likely to have a less rich mix of elements compared to our yellow G-type Sun. In May, Kepler added a record 1,284 confirmed planets, nine of which orbit in their sun's habitable zone.
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Nerds in a pub? (Score:2)
two of them may experience radiation levels from their star comparable to those on Earth
No! (Score:2)
The summary title contradicts the first sentence of the summary. And the sentence is correct, not the summary. Kepler doesn't confirm exoplanets, kepler gives a list of candidates. Its the opposite job. The confirmation is done on earth.
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Kepler could have confirmed exoplanet, unfortunately he is a few centuries too old for this.
Netcraft confirms it! (Score:2)
Pedigree (Score:2)
Doesn't that depend on the history of the parent stars that came before them? Perhaps they are less likely to have lots of elements, but since there are more red dwarfs, the total quantity coming from a "rich" parent(s) should be higher. But perhaps they are comparing p
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The point being that red dwarf stars burn for a long time, so on average they're very old, and older stars formed before large quantities of heavier elements existed.
Not accounting for the fact that the star (and by extension it's satellites) would have formed in a different environment from what is out there now, is disregarding the star's lifecycle. Satellites orbiting a red dwarf stars are probably poorer in heavy elements than those orbiting a G type star as the red dwarf is probably much older by enoug
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Maybe red dwarfs systems tend to come from parent stars that produce few elements? Just a guess since this is not my field of course the story could just be totally wrong about that. I have little faith in Slashdot summaries and I did not find that statement in the post from NASA.
Re: Pedigree (Score:1)
Red dwarfs have long life spans. This means that on average they are old stars. Old stars have low metal content because relatively few stars had time to supernova to synthesize and spread heavier elements by the time the red dwarf was formed.
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Small, red dwarf stars are "that way" merely because they have lower mass. So there's nothing systematically different about the amount of heavy elements in them, relative to Sun-like stars. In fact, our study said nothing at all about the likelihood of these planets to host life -- our knowledge of the requirements for that are slim enough, and our understanding of these new planets still too shallow, to say anything definitively about life on these planets.
Also, so far there is no clear sign that the occ
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That is why I said that the summary could be wrong and it looks like it is. As to knowing what is needed for life we do know that just do not know the limits yet. The questions about life on a planet around a red dwarf are interesting to say the least. Would the spectrum allow for photosynthesis? How well would it penetrate an ocean? Also the fact that a red dwarf could be stable for a very long time is also interesting as far as the development of intelligent life goes.
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Another alleged problem with red dwarf systems is that planets are more likely to be tidally locked,
That has nothing to do with the colour (red) or size (dwarf) of the sun but with the distance of the planet to the sun and "time". I'm not sure, but I was of the opinion even Earth is far enough away to never be tidal locked.
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Planets, within the habitable zone, for red dwarfs would likely be tidally locked, as the distance then is actually a function of the color (as a proxy for temperature) and size of the star.
Earth is far enough away to never be tidal locked.
Earth has a tidal locking timescale of ~30 billion years, although a resonance is an alternative outcome. That is too long for the given age of the universe, but considering that scales roughly like the sixth power of distance, you don't have to move much closer to shorten the timescale. Move a lot closer, and you make
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Earth's rotation is due to eventually become tidally locked with the Moon's rotation. That may override the Sun's influence, at least until the Moon crashes into Earth, if the universe lasts that long.
The Moon is due to get further away by stealing rotational momentum from Earth. However, once tidally locked, it will gradually get closer.
Yellow stars are the best (Score:2)
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Indeed -- but what we didn't know about planets back in the MoO era could fill a lot of modern exoplanet textbooks. Nonetheless, I'm sure all my hours of MoO-playing as a child (and after) helped contribute to me writing this big paper.
That's great! (Score:2)
Now we just need to figure out how to get there (or anywhere but here).