Three nearly Earth-size planets found orbiting nearby star

Phys.Org ^ | Jan 16, 2015 | Provided by University of Arizona

[Red Badger]

NASA's Kepler Space Telescope, despite being hobbled by the loss of critical guidance systems, has discovered a star with three planets only slightly larger than Earth. The outermost planet orbits in the "Goldilocks" zone, a region where surface temperatures could be moderate enough for liquid water and perhaps life, to exist.

The star, EPIC 201367065, is a cool red M-dwarf about half the size and mass of our own sun. At a distance of 150 light years, the star ranks among the top 10 nearest stars known to have transiting planets. The star's proximity means it's bright enough for astronomers to study the planets' atmospheres to determine whether they are like Earth's atmosphere and possibly conducive to life.

"A thin atmosphere made of nitrogen and oxygen has allowed life to thrive on Earth. But nature is full of surprises. Many exoplanets discovered by the Kepler mission are enveloped by thick, hydrogen-rich atmospheres that are probably incompatible with life as we know it," said Ian Crossfield, the University of Arizona astronomer who led the study.

A paper describing the find by astronomers at the University of Arizona, the University of California, Berkeley, the University of Hawaii, Manoa, and other institutions has been submitted to Astrophysical Journal and is freely available on the arXiv website.

Co-authors of the paper include Joshua Schlieder of NASA Ames Research Center and colleagues from Germany, the United Kingdom and the U.S.

The three planets are 2.1, 1.7 and 1.5 times the size of Earth. The smallest and outermost planet, at 1.5 Earth radii, orbits far enough from its host star that it receives levels of light from its star similar to those received by Earth from the sun, said UC Berkeley graduate student Erik Petigura. He discovered the planets Jan. 6 while conducting a computer analysis of the Kepler data NASA has made available to astronomers. In order from farthest to closest to their star, the three planets receive 10.5, 3.2 and 1.4 times the light intensity of Earth, Petigura calculated.

"Most planets we have found to date are scorched. This system is the closest star with lukewarm transiting planets," Petigura said. "There is a very real possibility that the outermost planet is rocky like Earth, which means this planet could have the right temperature to support liquid water oceans."

University of Hawaii astronomer Andrew Howard noted that extrasolar planets are discovered by the hundreds these days, though many astronomers are left wondering if any of the newfound worlds are really like Earth. The newly discovered planetary system will help resolve this question, he said.

"We've learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy," Howard said. "We also discovered some Earth-size planets that appear to be made of the same materials as our Earth, mostly rock and iron."

Kepler's K2 mission

After Petigura found the planets in the Kepler light curves, the team quickly employed telescopes in Chile, Hawaii and California to characterize the star's mass, radius, temperature and age. Two of the telescopes involved, the Automated Planet Finder on Mount Hamilton near San Jose, California, and the Keck Telescope on Mauna Kea, Hawaii, are University of California facilities.

The next step will be observations with other telescopes, including the Hubble Space Telescope, to take the spectroscopic fingerprint of the molecules in the planetary atmospheres. If these warm, nearly Earth-size planets have puffy, hydrogen-rich atmospheres, Hubble will see the telltale signal, Petigura said.

The discovery is all the more remarkable, he said, because the Kepler telescope lost two reaction wheels that kept it pointing at a fixed spot in space.

Kepler was reborn in 2014 as 'K2' with a clever strategy of pointing the telescope in the plane of Earth's orbit, the ecliptic, to stabilize the spacecraft. Kepler is now back to mining the cosmos for planets by searching for eclipses or "transits," as planets pass in front of their host stars and periodically block some of the starlight.

"This discovery proves that K2, despite being somewhat compromised, can still find exciting and scientifically compelling planets," Petigura said. "This ingenious new use of Kepler is a testament to the ingenuity of the scientists and engineers at NASA. This discovery shows that Kepler can still do great science."

Kepler sees only a small fraction of the planetary systems in its gaze: only those with orbital planes aligned edge-on to our view from Earth. Planets with large orbital tilts are missed by Kepler. A census of Kepler planets the team conducted in 2013 corrected statistically for these random orbital orientations and concluded that one in five sun-like stars in the Milky Way Galaxy have Earth-size planets in the habitable zone. Accounting for other types of stars as well, there may be 40 billion such planets galaxy wide.

The original Kepler mission found thousands of small planets, but most of them were too faint and far away to assess their density and composition and thus determine whether they were high-density, rocky planets like Earth or puffy, low-density planets like Uranus and Neptune. Because the star EPIC-201 is nearby, these mass measurements are possible. The host star, an M-dwarf, is less intrinsically bright than the sun, which means that its planets can reside close to the host-star and still enjoy lukewarm temperatures.

According to Howard, the system most like that of EPIC-201 is Kepler-138, an M-dwarf star with three planets of similar size, though none are in the habitable zone.

Explore further: Eight new planets found in 'Goldilocks' zone

More information: A nearby M star with three transiting super-Earths discovered by K2, arxiv.org/pdf/1501.03798v1.pdf

Journal reference: arXiv search and more info website Astrophysical Journal search and more info website

[Red Badger]

This whimsical cartoon shows the three newly discovered extrasolar planets (right) casting shadows on their host star that can been seen as eclipses, or transits, at Earth (left). Earth can be detected by the same effect, but only in the plane of Earth's orbit (the ecliptic). During the K2 mission, many of the extrasolar planets discovered by the Kepler telescope will have this lucky double cosmic alignment that would allow for mutual discovery—if there is anyone on those planets to discover Earth. The three new planets orbiting EPIC 201367065 are just out of alignment; while they are visible from Earth, our solar system is tilted just out of their view. Credit: K. Teramura, UH IfA.

[Red Badger]

Space ping!......................

[McGruff]

Wonder if they will will be watching the State of the Union speech tonight. If so, someone needs tell them it’s not a comedy.

[twhitak]

Wonder if they will will be watching the State of the Union speech tonight.

If they are intelligent, then the answer is "no."

[cicero2k]

“We’ve learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy,”

And the drumbeat of our demotion continues.

Starting with Galileo during the Renaissance, the discovery of DNA in the 1950s, and now this.

[b4its2late]

Neat stuff

[TexasCajun]

This will only confuse those QVC shopping channel hosts who couldn’t decide if our own moon was a star or planet.

[brownsfan]

These planets are found by inference, not direct observation. With all the global warming hysteria, I’ve lost a lot of confidence in the fidelity of our current scientific community.

[Cry if I Wanna]

The outermost planet orbits in the "Goldilocks" zone, a region where surface temperatures could be moderate enough for liquid water and perhaps life, to exist.

While Earth is certainly in a Goldilocks zone, we have many other things in our favor. For one, the massive planet Jupiter is relatively close, and its gravity keeps most asteroid's from hitting Earth. Earth-like planets in Goldilocks zones may have nice temperatures but the constant asteroid collisions could make life unlikely except for the tiniest of creatures.

[rdl6989]

back to the top

[SunkenCiv]

• Three New Earth-Size Planets Found "Nearby"

Thanks Red Badger.

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Google news searches: exoplanet · exosolar · extrasolar ·

[Red Badger]

Even the tiniest of creatures is a miracle of the highest order. Science cannot create even a single celled amoeba with all their knowledge...................

[Sasparilla]

We won’t ever see those in person unless Effram Cochrane steps up soon with a warp drive.

[Bloody Sam Roberts]

"It's life, Jim but not as we know it.
Not as we know it.
Not as we know it."

[Bloody Sam Roberts]

who couldn’t decide if our own moon was a star or planet.

Well, according to uber-fag Isaac Mizrahi, it's a planet because it has 'things' living on it.

[Repeal 16-17]

So should we force Liberals to move to one of those planets or should we move ourselves?

[Red Badger]

Give a hoot! Don’t Pollute!.............

[BigEdLB]

It is 150 light years away, so they can’t see it for 150 years By then we will be traveling through wormholes to get there immediately,m, and be able to warn them of the scarey man coming on the TV.

[TigersEye]

Fire up the rockets! No liberals allowed. Stowaway libs will be jettisoned in deep space.