Kepler Confirms Exoplanet Inside Star's Habitable Zone 257
astroengine writes "Plenty of 'candidate' exoplanets exist, but for the first time, Kepler has confirmed the existence of an exoplanet orbiting its Sun-like star right in the middle of its 'habitable zone.' Kepler-22b is 2.4 times the radius of Earth and orbits its star every 290 days. 'This is a major milestone on the road to finding Earth's twin,' said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. 'Kepler's results continue to demonstrate the importance of NASA's science missions, which aim to answer some of the biggest questions about our place in the universe.'"
Re:More info about the star? (Score:5, Informative)
I've looked a bit this morning and can't find anymore info about the star itself. What its apparent magnitude it? What constellation its in? Etc.
All I can figure out is its referred to as Kepler 22 which only makes sense in relation to the program. But I'd love to be able to try and see the star through a telescope.
Go to the exoplanet encyclopedia website instead of a place that headlines "Psychics and Missing Babies -- Dissecting the Blame Game" and "Top Tips from 2011 to Help Earth, Economy: Photos"
http://exoplanet.eu/star.php?st=Kepler-22 [exoplanet.eu]
Son of a B, e.eu has got nothing. Simbad's got nothing. There is nothing at all other than it exists and there are press releases all over along with fluffy talk about the release. But even the "official record" has nothing. Give it time and it'll get populated. Heck by the time you read this, e.eu might have data.
This is what Kepler-16 looks like on simbad, someday we'll have this level of data for -22
http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Kepler-16 [u-strasbg.fr]
I donno what a simbad is, a friend of mine went around calling it "sinbad" like the sailor for a while. Which is probably a cooler name, at least in the US.
Re:Habitable Planets (Score:3, Informative)
They're hundreds of light years away and we've only been communicative for less than a century. Given the inverse square law, communication between systems will probably need to be very intentionally focused with high gain antennae. In order for a message to have been sent to us that we can pick up, someone else would have had to see our planet in the habitable zone, see the oxygen levels in the atmosphere and attempt contact. They may have done so 50 times already, and would have gotten nothing back-- because we have to do the same with them to know which star to listen to and we're *still* not at that point.
tldr; physics.
Re:Habitable Planets (Score:4, Informative)
Say we find only 100 "habitable" planets...
Considering how very small the patch of sky Kepler is watching actually is, if we find 100 "habitable" planets in it, and then extrapolate that across the rest of the sky, the number of potential habitable planets would be huge. Of course, right now there are only around 54 or so habitable zone candidates, out of 1000 "planet" candidates, and all of them are still waiting for confirmation. Still, if even half of those are valid, then that indicates a massive number of qualifying planets in the galaxy.
For the interested, here's a link to a NASA graphic of Kepler's search zone:
http://www.nasa.gov/mission_pages/kepler/multimedia/images/kepler-target-in-the-milkyway.html [nasa.gov]
Re:habitable maybe (Score:3, Informative)
Re:600 light years... (Score:4, Informative)
Agreed. If it's the same density then 2.4x radius would be 14x the mass. I'm trying to picture a planet with intelligent pancake beings.
Hal Clement did a nice job in Mission of Gravity [wikipedia.org]. The planet Mesklin has 3 g at the equator and 700 g at the poles. Nice read. Clement knows his physics, so it is quite interesting on that level as well.
Re:Take that... (Score:5, Informative)
Best example of this: radio waves. Hertz tried to prove that Maxwell's equations were bogus, because if they were correct there would be ridiculous things such as electromagnetic waves between antennas. It works, bitches!
Wrong. Hertz created setups to deliberately try to prove that electric fields (and magnetic, but same thing) move at a speed less than infinite, to prove that Maxwell was right, not that he was wrong. Hertz also showed that light was an electromagnetic wave (or, rather, that they traveled at the same speed), and speculated that you could create light directly by ultra-high-frequency AC currents.
Re:More info about the star? (Score:5, Informative)
I'm no expert on this but I've got an awesome app on my iPhone called Exoplanet. It's always got new planets like this one before I even read about them.
The host star is KIC10593626
It's mass is 0.97 solar masses
It's radius is 0.98 solar radii
It's 587.1ly away
Stellar Metallicity is 0.000[Fe/H]
Spectral type is G5
Magnitude (V) 0.000
Right ascension is 19h 17m 70s
Declination is +47* 52' 90"
Hope that helps you, And please tell me if you think this would be visible through a telescope. There's a dark sky preserve near here with a 20" telescope that I've been meaning to visit
Re:More info about the star? (Score:5, Informative)
Re:Take that... (Score:5, Informative)
Kepler can only see planets with orbits that are edge-on, so they pass in front of the star and make a noticeable drop in it's brightness. Make the reasonable assumptions that the orbits are randomly distributed, and stars with planets in the habitable zone are also randomly distributed. Then we should expect that for every planet Kepler finds, there will be one 7 times as close it does NOT find, and another 340 more in between those distances it does not find.
Additionally, Kepler is only looking at 1/350th of the sky, in the direction of the constellation Cygnus. So add another factor of 350 more planets if you were searching in all directions. That gives you another factor of 7 in expected nearest distance.
Think of it this way: Kepler was not designed to find every nearby planet. It was designed to find the ones that happened to be in the right orbits so that it could see them, in a small part of the sky. It will give us a statistical sample of planets, from which we can estimate the total population. For each one it finds, there are 50-100,000 more out there, which is a LOT of planets.
It's much better than that! (Score:5, Informative)
Remember that Kepler looks at stars using the "transit" method. Basically it stares at the little point of light for a looooong time, never blinking and waits to see if the light drops just a teeny bit due to something passing in front of it. How long? Well since it has to calculate the orbital period, it must watch at bare minimum for at least 1 year to see 2 passes (assuming its looking for a planet in an earthlike orbit around a sun-like star). Then, in order to make sure that it isn't some OTHER planet passing in front of the star, or an object in our solar system, or "sun spots" on the star, or maybe space butterflies getting in the way, the scientists must wait for a THIRD confirming pass (at the predicted time of course with the same drop in intensity) to be sure the observation is "real".
I think these guys have found the first "earth-sized" object that has made three confirmed passes. Note that the period is a bit less than a year so they've had enough time to get three observations in the three years. Soon, they'll be announcing confirming "third passes" on more and more planets that have periods in roughly the one-year window that indicates it's in the habitable zone around a sun-like star.
There are two things to note here: First, Kepler can only see planets that pass between it and the target star, that is the planet's orbit must be almost exactly edge on for us to see it. How close to edge on must it be? Well for example; the earth's orbit is a circle (very) roughly 100 million miles from the sun and the sun is roughly 1 million miles across. So, if the orbit was tilted more than 1/100 or 1%, from some distant observer, they wouldn't see it cross in front. (The size of the earth is inconsequential in this calculation because it is so small in relation to the sun). Similarly, for the kind of planets Kepler is looking at circling around sun-like stars, we are only seeing BY PURE CHANCE 1% of them. So if we see 100 planets circling these stars in their habitable zone; that means there are really 10,000 of them! So for a sample size of 150,000 stars, that means that one out of every 15 sunlike stars has planet in it's habitable zone! Amazing, especially when you consider our galaxy to have perhaps 10 BILLION sunlike stars!
Secondly, Kepler was launched before astronomers "discovered" that the best place to find "habitable" planets wasn't around sunlike stars but around smaller cooler stars. For various reasons, the habitable zone (where water can be a liquid) is proportionately larger in these "mini" solar systems (everything is smaller, like the orbits). They realized that even if a planet was tidally "locked" so that one face was always facing the sun, the atmosphere would redistribute the heat enough so the planet would be "habitable" (must sure be windy though). Another advantage is that these smaller stars live much longer than our sun giving life longer to come to well... life! Finally these smaller stars are much more numerous than sunlike stars. Anyway, I think Kepler was focusing mainly on sunlike stars and not these smaller, more numerous and perhaps easier to detect (because the orbits are smaller you don't have to wait as long for three passes) targets. Maybe Kepler II will go after them!
Just so that you know, Kepler is likely (has already?) been giving tons of other interesting data. I understand that its sensors are sensitive (and stable enough!) so as to detect possible sunspots in these stars. Also by paying close attention to the timing of the transits, they can determine whether other planets are gravitationally "tugging" at the transiting planet and perturbing its orbit (that's how Neptune was discovered). Finally, the resolution of the 'light curve" of the transit may be sharp enough to reveal any large moons in orbit around the transiting planet. So even if the planet in the habitable zone is too large to support life as we know it, it may have a right sized moon! (think "Pandora").