First potentially habitable Earth-sized planet confirmed

[TheRussianRocket.]

http://phys.org/news/2014-04-potentially-habitable-earth-sized-planet-liquid.html?utm_content=buffer126b6&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer

The artist's concept depicts Kepler-186f, the first validated Earth-size planet orbiting a distant star in the habitable zonea range of distances from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that Earth-size planets exist in the habitable zone of other stars and signals a significant step closer to finding a world similar to Earth. The artistic concept of Kepler-186f is the result of scientists and artists collaborating to help imagine the appearance of these distant worlds. Credit: Danielle Futselaar

The first Earth-sized exoplanet orbiting within the habitable zone of another star has been confirmed by observations with both the W. M. Keck Observatory and the Gemini Observatory. The initial discovery, made by NASA's Kepler Space Telescope, is one of a handful of smaller planets found by Kepler and verified using large ground-based telescopes. It also confirms that Earth-sized planets do exist in the habitable zone of other stars.

"What makes this finding particularly compelling is that this Earth-sized planet, one of five orbiting this star, which is cooler than the Sun, resides in a temperate region where water could exist in liquid form," says Elisa Quintana of the SETI Institute and NASA Ames Research Center who led the paper published in the current issue of the journal Science. The region in which this planet orbits its star is called the habitable zone, as it is thought that life would most likely form on planets with liquid water.

Steve Howell, Kepler's Project Scientist and a co-author on the paper, adds that neither Kepler (nor any telescope) is currently able to directly spot an exoplanet of this size and proximity to its host star. "However, what we can do is eliminate essentially all other possibilities so that the validity of these planets is really the only viable option."

With such a small host star, the team employed a technique that eliminated the possibility that either a background star or a stellar companion could be mimicking what Kepler detected. To do this, the team obtained extremely high spatial resolution observations from the eight-meter Gemini North telescope on Mauna Kea in Hawai`i using a technique called speckle imaging, as well as adaptive optics (AO) observations from the ten-meter Keck II telescope, Gemini's neighbor on Mauna Kea. Together, these data allowed the team to rule out sources close enough to the star's line-of-sight to confound the Kepler evidence, and conclude that Kepler's detected signal has to be from a small planet transiting its host star.

The diagram compares the planets of the inner solar system to Kepler-186, a five-planet system about 500 light-years from Earth in the constellation Cygnus. The five planets of Kepler-186 orbit a star classified as a M1 dwarf, measuring half the size and mass of the sun. The Kepler-186 system is home to Kepler-186f, the first validated Earth-size planet orbiting a distant star in the habitable zonea range of distances from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that Earth-size planets exist in the habitable zone of other stars and signals a significant step closer to finding a world similar to Earth. Kepler-186f is less than ten percent larger than Earth in size, but its mass and composition are not known. Kepler-186f orbits its star once every 130-days and receives one-third the heat energy that Earth does from the sun, placing it near the outer edge of the habitable zone. The inner four companion planets all measure less than fifty percent the size of Earth. Kepler-186b, Kepler-186c, Kepler-186d, and Kepler-186e, orbit every three, seven, 13, and 22 days, respectively, making them very hot and inhospitable for life as we know it. The Kepler space telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA's first mission capable of detecting Earth-size planets around stars like our sun. Kepler does not directly image the planets it detects. The space telescope infers their existence by the amount of starlight blocked when the orbiting planet passes in front of a distant star from the vantage point of the observer. The artistic concept of Kepler-186f is the result of scientists and artists collaborating to help imagine the appearance of these distant Credit: Credit: NASA Ames/SETI Institute/JPL-CalTech.

"The Keck and Gemini data are two key pieces of this puzzle," says Quintana. "Without these complementary observations we wouldn't have been able to confirm this Earth-sized planet."

The Gemini "speckle" data directly imaged the system to within about 400 million miles (about 4 AU, approximately equal to the orbit of Jupiter in our solar system) of the host star and confirmed that there were no other stellar size objects orbiting within this radius from the star. Augmenting this, the Keck AO observations probed a larger region around the star but to fainter limits. According to Quintana,

The artistic concept of Kepler-186f is the result of scientists and artists collaborating to help imagine the appearance of these distant worlds. Credit: Credit: NASA Ames/SETI Institute/JPL-CalTech.

"These Earth-sized planets are extremely hard to detect and confirm, and now that we've found one, we want to search for more. Gemini and Keck will no doubt play a large role in these endeavors."

The host star, Kepler-186, is an M1-type dwarf star relatively close to our solar system, at about 500 light years and is in the constellation of Cygnus. The star is very dim, being over half a million times fainter than the faintest stars we can see with the naked eye. Five small planets have been found orbiting this star, four of which are in very short-period orbits and are very hot. The planet designated Kepler-186f, however, is earth-sized and orbits within the star's habitable zone. The Kepler evidence for this planetary system comes from the detection of planetary transits. These transits can be thought of as tiny eclipses of the host star by a planet (or planets) as seen from the Earth. When such planets block part of the star's light, its total brightness diminishes. Kepler detects that as a variation in the star's total light output and evidence for planets. So far more than 3,800 possible planets have been detected by this technique with Kepler.

The Gemini data utilized the Differential Speckle Survey Instrument (DSSI) on the Gemini North telescope. DSSI is a visiting instrument developed by a team led by Howell who adds, "DSSI on Gemini Rocks! With this combination, we can probe down into this star system to a distance of about 4 times that between the Earth and the Sun. It's simply remarkable that we can look inside other solar systems." DSSI works on a principle that utilizes multiple short exposures of an object to capture and remove the noise introduced by atmospheric turbulence producing images with extreme detail.

Observations with the W.M. Keck Observatory used the Natural Guide Star Adaptive Optics system with the NIRC2 camera on the Keck II telescope. NIRC2 (the Near-Infrared Camera, second generation) works in combination with the Keck II adaptive optics system to obtain very sharp images at near-infrared wavelengths, achieving spatial resolutions comparable to or better than those achieved by the Hubble Space

Telescope at optical wavelengths. NIRC2 is probably best known for helping to provide definitive proof of a central massive black hole at the center of our galaxy. Astronomers also use NIRC2 to map surface features of solar system bodies, detect planets orbiting other stars, and study detailed morphology of distant galaxies.

"The observations from Keck and Gemini, combined with other data and numerical calculations, allowed us to be 99.98% confident that Kepler-186f is real," says Thomas Barclay, a Kepler scientist and also a co-author on the paper. "Kepler started this story, and Gemini and Keck helped close it," adds Barclay.

[TheRussianRocket.]

From another source:

SPACE

APRIL 17, 2014

Kepler Team Announces Discovery of Earth-Sized Planet in Habitable Zone

Since its launch in the spring of 2009, NASA's Kepler Space Telescope has been hunting exoplanets. The holy grail being a planet that is essentially like ours in terms of size, composition, and habitability: an Earth-twin. While we still haven't found a planet that exactly fits that bill, Kepler has now confirmed the discovery of an Earth-sized exoplanet in its star’s habitable zone. The announcement was made at a press conference and the findings have been published in Science.

Kepler-186f is about 10% larger than Earth and orbits an M dwarf star around 500 light-years away in the constellation Cygnus. The star is about half of the size and mass of our sun, and it takes Kepler-186f about 130 Earth days to complete a revolution. On the outer edge of the star’s habitable zone, the planet receives about a third of the radiation from its parent star as we do from ours.

Life as we know it requires the presence of liquid water, so a planet with the potential for life would be not too close to the star (which would be too hot and the water would be vapor) yet not too far away (where it would be too cold and the water would be ice). Habitability requires a “Goldilocks Zone” where conditions are just right.

"We know of just one planet where life exists -- Earth. When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth," said Elisa Quintana, lead author of the paper. "Finding a habitable zone planet comparable to Earth in size is a major step forward."

Co-author Thomas Barclay added: "Being in the habitable zone does not mean we know this planet is habitable. The temperature on the planet is strongly dependent on what kind of atmosphere the planet has. Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth."

Determining the composition of planets out in the habitable zone isn’t as easy as those who are incredibly close to the star, because there isn’t as much radiation from the parent star available to determine what is or isn’t getting absorbed. While previous findings have indicated that Kepler-186f is a rocky planet, further analysis must be done before any definitive conclusions can be made.

Have questions for the scientists? Ask them using #Kepler186f on Twitter, Facebook, or G+.

Correction 4/17/2014 1:30 pm PDT: An earlier version of this article stated the planet was 40% larger than Earth. That was a typo; Kepler-186f is 10% larger than Earth. Apologies for any confusion that error may have caused

This is huge news. There have been reports and stuff before of Earth like planets but this is the closest one yet and the evidence is more than convincing at this point. More positives than negatives here and this seems like the real deal. Now obviously there won't be any humans going there for a while but this will at least confirm the inevitable that we aren't the only ones out there.

[Malkin Cookies]

Wow that's really cool

[NightHawkSniper]

I'd rather go there than Mars, but I'd most likely die from the time heading there.

[-Vintage Canuck-]

How a sunset might look on Earth's new cousin Kepler-186f.

[kurtis]

wow this is crazy. For sure were not alone.. Anyone who thinks other wises needs to give there head a shake...

[Silfverberg Snipes]

At first I was excited, now I'm scared. Fucking aliens man.

[Derp...]

DO THEY KNOW ABOUT US YET?

DOES KEPLER-186f KNOW ABOUT US???

Who would they draft? International like Kapanen?

[TheRussianRocket.]

At first I was excited, now I'm scared. ???? aliens man.

Well, Earth and us are aliens in the eyes of people on other planets but we're not that scary are we?

[L. Stanley]

DO THEY KNOW ABOUT US YET?

DOES KEPLER-186f KNOW ABOUT US???

Who would they draft? International like Kapanen?

i thought that myself, but I bet they'd goafter a gritty candian - virtanen, ritchie, mccann

[NucksCup2015]

I find it odd that with the simple probability that we are not alone, people want to cling to this idea of God and us being the only intelligent life in the universe.

Firstly, we are babies in the universe, Hawking has said this, if we are to ever meet life (perhaps we shouldn't has he has said, as they may not be the romantic/enlightened idea we believe them to be) does that remove the potential for God? No, people who are religious can cling to the idea that a being created the universe and all life, that is fine.

I think of math and science and probability, it is very ego centric (as we humans are) to assume we are alone....

Personally, I wish I was alive the day we finally make contact with another intelligent life form, that being said, how we are destroying this planet, we may not be alive long enough....

Humanity really needs to come together to focus on what is challenging our race (HUMAN RACE) and put aside these petty issues we have.

Explore, attain knowledge, and maybe we last long enough to meet whatever is out there

[Jägermeister]

I always find this interesting when we find it, but it isn't the least bit surprising.

You'd have to be ignorant to not think there is other lifeforms out there somewhere.

[Plum]

I wonder if Humans live there...

[Silfverberg Snipes]

Well, Earth and us are aliens in the eyes of people on other planets but we're not that scary are we?

I dunno, maybe one day we'll talk about it over a game of chess.

[TheRussianRocket.]

I find it odd that with the simple probability that we are not alone, people want to cling to this idea of God and us being the only intelligent life in the universe.

Lul, somehow got God in here didn't you? Idk where you came to assumption with that but that's totally incorrect lol. Just so much wrong with that, lel.

[DUKEskywalker]

I firmly believe there has to be another life form out there somewhere. No way are we the only ones that occupy this galaxy or universe. I see us as the babies of the universe being recent. I always had a feeling that there was someone else out there. Intelligence wise I believe we are not there yet. Other life forms out there I can see them being a lot smarter then us. We are still not at that advanced stage yet. I am 19 years old and I hope I get to see the day we find others out there. Probably wont happen though

[TheRussianRocket.]

I firmly believe there has to be another life form out there somewhere. No way are we the only ones that occupy this galaxy or universe. I see us as the babies of the universe being recent. I always had a feeling that there was someone else out there. Intelligence wise I believe we are not there yet. Other life forms out there I can see them being a lot smarter then us. We are still not at that advanced stage yet. I am 19 years old and I hope I get to see the day we find others out there. Probably wont happen though

Without a doubt. There have been numerous Earth like planets before us which have been developed and destroyed just like how this planet will go through. It's the nature of the universe and to think we are the only ones is quite ridiculous.

However, finding an Earth like planet while in our existence is pretty tremendous.

[DarthNinja]

I wonder if Humans live there...

maybe it's the folk'n prawns yeh?

[DefCon1]

DO THEY KNOW ABOUT US YET?

DOES KEPLER-186f KNOW ABOUT US???

Who would they draft? International like Kapanen?

I think they do. Here is what NASA caught on their telescope (based on the artist's concept)

[DarthNinja]

*I'm not sure what was/is bigger news, this or Kepler 22-b in 2011, which was the first official earth-like planet found in the habitable zone of a star. After finding one, I suppose it's only a matter of time...

But this still, this is so cool!

I'd rather go there than Mars, but I'd most likely die from the time heading there.

On the plus side, if you can travel the speed of light, it will only take you 500 years to get there!