Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: redsniper on April 11, 2013, 08:33:41 pm
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http://io9.com/an-earth-sized-planet-is-orbiting-the-nearest-star-472536843
Happily for everyone, astronomers at the European Southern Observatory in Chile recently discovered a planet with a mass similar to that of the earth orbiting the sun-like Alpha Centauri B. Indeed, Alpha Centauri Bb is the first planet with an earth-like mass ever found orbiting a sun-like star.
[20:31] <@Axem> oooooh
[20:31] <@Axem> red
[20:31] <@Axem> http://io9.com/an-earth-sized-planet-is-orbiting-the-nearest-star-472536843
[20:31] <@Axem> ITS HAPPENING
[20:31] <redsniper> **** ME
[20:32] <redsniper> omg
[20:32] <@Axem> i, for one, welcome our new mindworm overlords
Time to pick factions and brace for mindworms. Also, in b4 naysayers, parade rainers, and party poopers. It's SMAC IRL, let us have our fun.
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Calling Univeristy. Proctor Axem has a nice ring to it.
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Spartans 4 lyfe
I don't know what I been told!
Deidre's got a network node!
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Oh man, what are we going to do without Lord Battuta?
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He'll be back and for now we'll carry on. Let's not make this about forum politics at all. In the meantime, look forward to Herra, perihielion, etc.
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Oh sweet. Sucks that it orbits so close to Centauri B that it's probably a cinder, though. :(
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Oh sweet. Sucks that it orbits so close to Centauri B that it's probably a cinder, though. :(
It's simple
We move the Centauri B
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Well, the odds are it's interesting, but not viable, but there always is the very slim chance it is gravitationally locked, which might render it not totally useless.
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But... Proxima is the closest star! The headline of the article is wrong!
...Otherwise, where is my warp drive?!!
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Well, you need to consider that its much easier to find a planet that's closer to the sun. It has a larger chance to be transiting its star at any given point and from findings about other star systems, planets don't seem to be just single cases.
I bet if aliens were looking at our system and saw Mercury passing the sun they would go, "Meh, too close to the star, nothing to see there."
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But... Proxima is the closest star! The headline of the article is wrong!
...Otherwise, where is my warp drive?!!
Actually, Proxima Centauri is a part of Alpha Centauri trinary system. It's also known as Alpha Centauri C. So the article is right.
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If you wish to get extremely pedantic, it is... right. The article headline says "An Earth-Sized Planet is Orbiting the Nearest Star". The nearest star, is of course, our sun! And Earth and Venus are both Earth-sized... so hey, its technically right.
But more to the point, the next nearest star is Proxima Centauri, which the planet is not orbiting around. So in that context, the headline is wrong. "An Earth-Sized Planet found in Alpha Centauri" would be correct.
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Whoop!!! Closest exoplanet yet detected FTFW! It's only been roughly 20 years since the first one was detected orbiting a pulsar. Now we've progressed to right next door! It's only a matter of time, now, before we find one in the sweet spot. The sky is just chock full of planets!
Flip's right, too. If it is orbiting that close to its primary, the dayside is likely to be a radioactive deathzone. But odds are also that it will be tidally locked... I wonder. That close to its sun, you'd have to expect solar radiation to have pretty much stripped it of its atmosphere like Mercury, tidally locked or not. But I'd never really given much thought to what would happen if it were a planet the Earth's size, with enough gravity to hold on to an atmosphere reasonably well.
Man. Weather could be seriously weird if does have an atmosphere.
EDIT: Having a serious nerdgasm here! SQUEEE!!!!
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Here's the original discovery paper, published in October: http://www.eso.org/public/archives/releases/sciencepapers/eso1241/eso1241a.pdf
Though too close to its star to be of astrobiological interest, it makes the system look a lot more promising, now that we know at least one planet has formed there, there's probably going to be more. And since it's so close its further evidence of how common planets are in the galaxy. It's an awesome time in astronomy.
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I call mother****ing Yang
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I'm gonna nerve staple. Come at me
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I call mother****ing Yang
I'm gonna nerve staple. Come at me
As CEO IronBeer of IronBeer Industries, I sneer at your pitiful -2 ECON rating. The monied and learned elite shall triumph over the slavering peasant mass of the Hive!
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Eh, I like io9, but they're way behind on this. This planet was discovered last year.
Nature article (http://www.nature.com/nature/journal/v491/n7423/full/nature11572.html)
In fact, it is the lightest exoplanet yet discovered.
At the time it was discovered, maybe, but exoplanet discoveries are proceeding pretty fast, and the record for smallest planet currently goes to this (http://www.nature.com/nature/journal/v494/n7438/full/nature11914.html).
Also, take the claim that this planet is Earth-sized with a grain of salt. Popular articles like to report the mass of planets detected via the radial velocity method as if it's the real value. It isn't. For all we know this planet could be many times heavier.
The problem is that the mass of an exoplanet is determined as a function of its orbital inclination angle. The less edge-on the orbit is from our perspective, the smaller the component of the star's velocity due to the planet we measure, and the more we underestimate the planet's mass. Therefore what astronomers are reporting is the minimum mass, Msini, where i is the inclination angle. The only ways we can only measure this angle if we can image the planet directly and trace the orbit, or if it happens to transit its host star in which case the angle is 90°. Statistically, most planets have true masses pretty close to that minimum, but it is not good to keep saying that it is equal.
Still, this is a really nice find, and does support the hypothesis that most or even all stars bear planetary systems. This was also an extremely difficult detection, requiring a radial velocity measurement precise to only half a meter per second. That's incredible.
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i would want to know how stable that system is, considering the highly elliptical orbit of alpha centauri b. seems like it would play havok with everything when it gets to its perihelion.
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Apparently stable enough not to take this planet out of its orbit. However, it's highly unlikely for there being a planet in the habitable zone of both these stars. If there's an interesting planet in alpha centauri, it's probably lurking in proxima.
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At closest approach the stars are about 11 AU from each other. Planets orbiting the B star can have stable orbits up to about 3 or 4 AU. For comparison, the planet in question orbits at roughly 0.04 AU.
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Apparently stable enough not to take this planet out of its orbit. However, it's highly unlikely for there being a planet in the habitable zone of both these stars. If there's an interesting planet in alpha centauri, it's probably lurking in proxima.
Proxima Centauri is a rather pathetic red dwarf. I wouldn't count on anything habitable around it. On the other hand, both Alpha Centauri A and B are comparable to Sun and given 11AU distance between them, their habitable zones probably wouldn't really intersect (at least from what I know. Alpha Centauri is a complex system).
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Proxima Centauri is a rather pathetic red dwarf. I wouldn't count on anything habitable around it.
Astronomers used to think this as well, but recently we have been finding out that habitability is very complex, and a few studies have shown that we can't rule out the existence of habitable planets around M-dwarf stars afterall. :)
You're correct about the habitable zones of α Cen A and B (going with the original and somewhat dated definition of the term). There would be one of these zones around each of the two stars, of about the same size as Sol's, and orbits within these zones would be stable over million+ year periods.
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Eh, I like io9, but they're way behind on this. This planet was discovered last year.
Well no one told me about it! :p
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Astronomers used to think this as well, but recently we have been finding out that habitability is very complex, and a few studies have shown that we can't rule out the existence of habitable planets around M-dwarf stars afterall. :)
But the habitable zone around an M-class red dwarf would be so close to the star that any flare activity would utterly crispy-critter any life on the surface. I thought that had been accepted for decades. Has that understanding changed, or is there some other scenario that might push the "habitable zone" further out from even such a dim star?
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You are correct on the increased solar activity and flaring, but its implications for habitability are not that simple. :) Nor is it the only factor to habitability that needs to be considered.
The biggest problem from solar activity is that it enhances atmospheric loss. Note, atmospheric loss comes in two flavors: thermal and non-thermal. Thermal loss depends on the atmosphere’s composition, its temperature, and the surface gravity of the planet. Non-thermal escape (which for most planets is less significant than many people seem to think) depends on solar wind activity / CME’s and the presence of a magnetic field. Studies have shown that solar activity from M stars would be a problem for earth-like worlds in their habitable zones, but super-earths would be fine. Radiation would not necessarily be a problem to surface life – much of this radiation is absorbed by the atmosphere itself. Life on the surface may also be protected underground or water, and it has been demonstrated that life can be very radiation tolerant. (Radiophiles) (http://en.wikipedia.org/wiki/Radioresistant)
Other important factor to consider is tidal locking. The time it takes for a planet to become tidally locked to its star depends strongly on its orbital distance, and the habitable zone of M-stars is very close, so planets may be expected to become synchronously rotating on much shorter timescales. This has implications for atmospheric stability, dynamics, and climate. There can even be such bizarre outcomes as complete atmospheric collapse, where the entire atmosphere literally freezes out on the cold anti-solar side of the planet. But studies have shown that there are a wide range of conditions for which the atmospheres of planets orbiting M-stars are stable.
Interested readers may find the following links informative:
http://online.liebertpub.com/doi/abs/10.1089/ast.2006.0125
http://online.liebertpub.com/doi/abs/10.1089/ast.2006.0128
http://online.liebertpub.com/doi/abs/10.1089/ast.2006.0124
http://online.liebertpub.com/doi/pdfplus/10.1089/ast.2006.0123
http://online.liebertpub.com/doi/abs/10.1089/153110703769016488
http://online.liebertpub.com/doi/abs/10.1089/ast.2005.5.706?journalCode=ast
http://www.sciencedirect.com/science/article/pii/S0019103597957936
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Eh, I like io9, but they're way behind on this. This planet was discovered last year.
Well no one told me about it! :p
Actually, we did. (http://www.hard-light.net/forums/index.php?topic=82587.0) :P
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Bugger all! How the heck did I forget this???
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Eh, I like io9, but they're way behind on this. This planet was discovered last year.
Well no one told me about it! :p
Actually, we did. (http://www.hard-light.net/forums/index.php?topic=82587.0) :P
:eek:
Well then I... forgot
... and got excited all over again.
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Yeah! I mean, I am having an "oh gosh I'm such a duffus" moment, but at the same time it is still AWESOME!!!!
[insert goofy grin here]