‘Star With 3 Super-Earth Exoplanets Just 21 Light Years Away’


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Astronomers said Thursday they had found a planetary system with three super-Earths orbiting a bright, dwarf star one of them likely a volcanic world of molten rock.
The four-planet system had been hiding out in the M-shaped, northern hemisphere constellation Cassiopeia, “just” 21 light years from Earth, a team reported in the journal Astronomy & Astrophysics.

It comprises four planets one giant and three super-Earths orbiting a star dubbed HD219134.

Super-Earths have a mass higher than Earth’s but are lighter than gas giants like Neptune, Saturn or Jupiter. They can be made of gas, rock, or both.

The planet with the shortest orbit, HD219134b, zips around every three days, and has now been observed transiting across the face of its star as seen from the vantage point of Earth.

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Measurements from the ground and with Nasa’s Spitzer space telescope showed its mass was 4.5 times higher than Earth’s, and that it was 1.6 times larger.

“Its mean density is close to the density of Earth, suggesting a possibly similar composition as well,” said a press statement from the University of Geneva, whose astronomers took part in the research.

“It’s very close to the star. The temperature is about 700 degrees” Kelvin (427 Celsius, 800 Fahrenheit), study co-author Stephane Udry told AFP.

“Probably the surface is melting… kind of a melted lava world with volcanoes… not good for life.”

It was not in the so-called “habitable zone” of its star, and would not have liquid water necessary for life.

But HD219134b is exciting for another reason: it is the closest transiting planet known to scientists, and thus offers a rare opportunity for further study of its composition and atmosphere against the backdrop of its star.

“These transiting systems are especially interesting in that they allow characterisation of the atmosphere of the planet (by studying) the light of the star going through the atmosphere,” Udry said.

And the system is relatively near at a distance of 21 light years from Earth. By comparison, the closest star to our Sun is three light years away, and the second six light years.

Among HD219134b’s fellow planets, the second furthest from the star weighs 2.7 times as much as Earth and orbits in 6.8 days, the next is 8.7 times more massive than Earth with a 47-day orbit.

A giant planet further out orbits once every three years, the team said.

Source : NDTV

Newly Discovered Exoplanet Is The Most Distant Ever Detected


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This artist’s conception shows the newly discovered alien planet also Known as OGLE-2014-BLG-0124Lb , which is about 13,000 light-years from Earth.

Astronomers have found an exoplanet nearly 13,000 light-years away, making it one of the most distant planets known to man. This discovery is important not because of the planet itself, a gas giant about half the size of Jupiter, but because what it means for the future of planetary discovery and mapping.

“For context, most of the planets we do know about are a factor of 10-100 times closer than OGLE-2014-BLG-0124,” Dr. Jennifer Yee, a NASA Sagan Fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge

Far, far away.

The microlensing technique has helped astronomers discover about 30 distant alien planets in our Milky Way’s bulge, the galaxy’s central area of mostly old stars, gas, and dust.

The farthest known exoplanet resides some 25,000 light years away in the bulge of our galaxy, Yee said in the email. The bulge is a very different environment from the Milky Way’s disk, where our own solar system is located.

According to Yee, no exoplanets have been found outside of our galaxy, which spans about 100,000 light years.

Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way. Using infrared images from NASA's Spitzer Space Telescope, scientists have discovered that the Milky Way's elegant s

This artist’s map of the Milky Way shows the location of some of the farthest known exoplanets, including OGLE-2014-BLG-0124Lb.

Comparing planets to planets. Astronomers hope not only to gain a better understanding of the distribution of planets in the Milky Way, but also to gather enough detail about distant planets to compare them with those closer to Earth. More than 1,000 exoplanets closer to home have been discovered by the planet-hunting Kepler mission and ground-based observatories, Space.com reported.

“We would really like to know whether planets form in the central bulge of our galaxy the same way that they do here, near the sun, where the overwhelming majority of planets have been found,” Dr. Andrew Gould, professor of math and physical sciences at Ohio State University, and a co-author of the paper describing the newfound exoplanet, told The Huffington Post.

The Christian Science Monitor reported that the Spitzer telescope is scheduled to observe about 120 more “microlensing” events this summer, which could lead to the discovery of even more distant exoplanets.

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This infographic explains how NASA’s Spitzer Space Telescope can be used in tandem with a ground-based telescope to measure the distances to planets using the “microlensing” technique.

Source: huffingtonpost

Massive Exoplanet Evolved in Extreme 4-Star System


According to a team of astronomers headed by Dr Lewis Roberts from NASA’s Jet Propulsion Laboratory in Pasadena, an extrasolar gas giant called 30 Arietis Bb (30 Ari Bb) is the second known example of a planet residing in a system with four stars.

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Artists conception of the 30 Ari star system. In the foreground is the primary star about which the massive exoplanet orbits. The primary’s newly-found binary partner, a red dwarf, can be seen in the upper left and the secondary binary system can be seen to the upper right.

While 30 Ari Bb was known before, it was thought to reside in a system of three stars, not four.

The system, called 30 Ari, is located in the constellation Aries, approximately 136 light-years away.

“Star systems come in myriad forms. There can be single stars, binary stars, triple stars, even quintuple star systems. It’s amazing the way nature puts these things together,” Dr Roberts said.

The planet itself is enormous, with 9.88 times the mass of Jupiter. It orbits its primary star, 30 Ari B, every 335 days. This star has a relatively close partner star, which the planet does not orbit.

The pair, in turn, is locked in a long-distance orbit with another pair of stars about 1,670 AU away.

“It’s highly unlikely that this planet, or any moons that might circle it, could sustain life,” Dr Roberts and his colleagues said.

The first four-star planet, Ph1b, was discovered in the star system Kepler-64 (KIC 4862625) in 2013 by astronomers using data from NASA’s Kepler mission.

The latest discovery, reported in the Astronomical Journal (arXiv.org preprint), suggests that exoplanets in quadruple star systems might be less rare than once thought.

The similarity between Kepler-64 and 30 Ari is that both systems are quadruples consisting of two relatively close pairs that are widely separated.

In fact, recent studies have shown that this type of star systems is itself more common than previously believed.

“About 4% of Sun-like stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving,” said team member Dr Andrei Tokovinin of the Cerro Tololo Inter-American Observatory in Chile.

The scientists also reported on a triple-star planetary system, HD 2638, which hosts a so-called hot-Jupiter.

This giant planet, named HD 2638b, orbits its primary star tightly, completing one lap every 3 days.

Source : sci-news.com

Planets orbiting Kepler 444 suggest there’s ancient life in the Milky Way


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NASA’s exoplanet hunting Kepler space telescope has encountered a few problems as of late, but there’s still a mountain of data for astronomers to dig through from the last four years. Astronomers analyzing Kepler data recently uncovered something unusual — a solar system about 117 light years away in the direction of Lyra called Kepler-444 with at least five Earth-sized planets. That would be unusual enough, but this planetary system is also extraordinarily ancient at roughly 11.2 billion years.

Astronomers are intrigued by this discovery for several reasons. First, that’s a lot of small rocky planets. Kepler detects alien worlds by the transit method. It watches distant suns for slight dips in brightness that indicate a planet has passed between it and the telescope. These events can be used to calculate the characteristics of the planet, but it works best for larger worlds (super Earths and gas giants). Spotting five planets between the size of Mercury and Venus (basically a little smaller than Earth) is unusual.

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Artistic Depiction of Kepler 444 with its Star

The age of Kepler-444 is also something to note. At 11.2 billion years old, the planets orbiting this star were already older than Earth is now when our sun ignited 4.5 billion years ago. The universe itself is only 13.8 billion or so years old, making Kepler-444 one of the oldest stars in the Milky Way. It would have been from the first generation of stars that dotted the sky. Kepler-444 is still very sun-like because it’s 25% smaller and cooler. That means it burns through its nuclear fuel more slowly.

Finding small rocky planets that are billions of years older than Earth suggests that advanced life may have existed in the universe for a very long time. Life on Earth might be very new by comparison. Just think, planets similar to Earth were forming more than 7 billion years before Earth formed, and some of them could have supported life. If other first-generation stars like Kepler-444 have planets, uncountable civilizations could have come into being eons before the first single-cell life appeared on Earth.

The planets orbiting Kepler-444 themselves are not able to support life as we know it. All five planets are packed very close to the parent star with orbits closer than that of Mercury in our solar system. With solar years less than 10 Earth days, they definitely stood out in the Kepler data. The surfaces of these worlds have been baked by the intense heat, reducing any organic material to cinders.

Kepler-444 isn’t a bastion of alien life, but it improves our understanding of planetary formation and points us in a new direction. Astronomers are anxious to find other ancient stars with rocky planets in hopes they might prove more hospitable to life. What if there was still something alive on one of these ancient worlds? That might sound like science fiction right now, but maybe it won’t always be — there’s still a lot of data from Kepler, and future telescopes will improve our ability to spy distant exoplanets.

Source: Geek.com

Scientists Discover Exoplanet With Rings Far More Impressive Than Our Saturn


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Artist’s conception of the extrasolar ring system circling the young giant planet or brown dwarf J1407b is shown. Credit: Ron Miller

Children and adults alike marvel at the rings around Saturn. In a model of our solar system, Saturn—and its rings—is typically the one that gets the most attention.

But while it is easy to be fascinated by Saturn, astronomers have recently found an exoplanet with an even grander expanse of wings that is sure to wow a new generation of stargazers.

“The star is much too far away to observe the rings directly, but we could make a detailed mode based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn’s rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon,” explains lead researcher Matthew Kenworthy. “The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings.”

Study co-author Eric Mamaek, who first found the rings of the planet, comments, “The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites. However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object.”

The University of Rochester professor of physics and astronomy goes on to say, “This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn’s rings are today. You could think of it as a kind of super Saturn.”

Source : piercepioneer.com

Nasa’s Kepler Discovers Star With 3 Planets Larger Than Earth


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Nasa’s Kepler space telescope has discovered a star with three planets only slightly larger than Earth.

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.

“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.

“Most planets we have found to date are scorched. This system is the closest star with lukewarm transiting planets,” added University of California Berkeley graduate student Erik Petigura.

Petigura discovered the planets January 6 while conducting a computer analysis of the Kepler data NASA has made available to astronomers.

“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,” he noted.

After Petigura found the planets in the Kepler light curves, the team quickly employed telescopes in Chile, Hawaii and California to characterise the star’s mass, radius, temperature and age.

The star’s proximity means it is bright enough for astronomers to study the planets’ atmospheres to determine whether they are like the Earth’s atmosphere and possibly conducive to life.

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 paper has been submitted to Astrophysical Journal and is freely available on the arXiv website.

Source : NDTV