Exoplanet Discoveries, discussion of the latest finds |
Exoplanet Discoveries, discussion of the latest finds |
Guest_PhilCo126_* |
Apr 21 2009, 11:10 AM
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Guests |
Well-known exoplanet researcher Dr Michel Mayor ( discoverer of Peg 51b with Dr Didier Queloz in 1995 ) today announced the discovery of the lightest exoplanet found so far. The planet, “e”, in the famous system Gliese 581, is only about twice the mass of our Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist:
http://www.eso.org/public/outreach/press-r...9/pr-15-09.html |
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Aug 14 2016, 01:30 AM
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#2
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
Just noticed that Der Spiegel and other online sources are reporting a pre-announcement about a
a terrestrial planet with liquid water around alpha centauri... Anybody hearing anything? |
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Aug 14 2016, 02:32 AM
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#3
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Google searches limited to the last week show several results; this is one:
http://phys.org/news/2016-08-scientists-un...ike-planet.html It is Proxima Centauri that is the host star; Proxima Centauri is believed to be part of the Alpha Centauri system, but it is quite remote from the other two and it is not certain that they are gravitationally bound. However, their distance from us is nearly equal. Any discovery like this would be very exciting, but I'm quite sure that at this point, the only thing anyone could say about liquid water would be speculation based on the amount of insolation a planet receives; actually detecting liquid water would be a much harder feat. I should say that Kepler data indicate that very roughly 8% of red dwarfs have Earth-sized planets in their habitable zone and roughly 8% have a Super Earth in their habitable zone… obviously this depends on definitions of HZ and the size bounds used. With a looser definition, the sum of those probabilities plus Mars-sized planets might climb over 50%. Which is to say: Without making any observations of Proxima Centauri, one could already saw that there's a good chance of a terrestrial planet with temperatures that could permit liquid water. One might even say that it's probable for each red dwarf. (Although this packs a lot of uncertainty into the "could permit liquid water" and definition of "terrestrial planet.") Furthermore, it seems nearly certain that one of the four or so closest red dwarfs should have a planet that meets those loose definitions. I'll be eager to hear more, though. Proxima Centauri is the absolute easiest star in the universe for follow-up science on its planetary system. It would be a nice bit of luck if a candidate "earthlike" planet were there. |
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