First aurora outside solar system discovery


Aurora on LSR J1835+3259

By Charles Q. Choi, Space.com Contributor in the USA:

First Alien Auroras Found, Are 1 Million Times Brighter Than Any On Earth

July 29, 2015 01:01pm ET

Astronomers have discovered the first auroras ever seen outside the solar system — alien light shows more powerful than any other auroras ever witnessed, perhaps 1 million times brighter than any on Earth, researchers say.

Auroras could soon be detected from distant exoplanets as well, investigators added.

Auroras, the radiant displays of colors in the sky known on Earth as the northern or southern lights, are also seen on all of the other planets with magnetic fields in the solar system. They are caused by currents in the magnetosphere of a planet — the shell of electrically charged particles captured by a planet’s magnetic field — that force electrons to rain down on the atmosphere, colliding with the molecules within and making them give off light. [Amazing Auroras on Earth in 2015 (Photos)]

To see if auroras might be seen outside the solar system, astronomers investigated a mysterious Jupiter-size object called LSR J1835+3259, located about 18.5 light-years from Earth. The object is a few dozen times more massive than Jupiter, suggesting it is too heavy to be a planet but too light to be a star, the researchers said.

They suggested that LSR J1835+3259 is a brown dwarf, a strange misfit object sometimes known as a failed star. As massive as brown dwarfs are compared to planets, they are too puny to force atoms to fuse together and release the nuclear energy that powers stars.

In 2001, scientists unexpectedly discovered that brown dwarfs could generate radio waves. “That was very surprising,” said Gregg Hallinan, an astronomer at the California Institute of Technology in Pasadena and lead author of the new study. “Typically, we see radio waves from really active stars, not objects with much cooler temperatures like brown dwarfs,” he told Space.com.

In 2008, Hallinan and his colleagues found that LSR J1835+3259 emitted radio waves in pulses. “We knew that radio pulses from planets in our own solar system were caused by aurorae, so we thought maybe brown dwarfs had aurorae too,” he said.

Using the Karl G. Jansky Very Large Array in New Mexico to scan radio wavelengths of light, along with the Hale Telescope on Palomar Mountain in California and the W. M. Keck Observatory in Hawaii to scan visible wavelengths of light, the researchers detected the telltale signs of auroras on LSR J1835+3259.

“If you were to somehow stand on the brown dwarf’s surface and survive — the surface gravity is maybe 100 times more intense than Earth’s, and the temperature is several hundred to several thousand degrees — you’d see a beautiful bright-red aurora,” Hallinan said. “The colors of auroras depend on whatever the atmosphere they take place in is made of. In Earth’s case, it’s mostly green and blue and red because of oxygen and nitrogen. When it comes to Jupiter, Saturn and brown dwarfs — which have hydrogen-rich atmospheres — you’d see red, and there would be ultraviolet and infrared wavelengths as well.”

Until now, the brightest known auroras came from Jupiter, which has the most powerful magnetic field in the solar system. In comparison, these newfound auroras are more than 10,000 times — and maybe 100,000 times — brighter than Jupiter’s, Hallinan said. This is because LSR J1835+3259 has a magnetic field perhaps 200 times stronger than Jupiter’s, he said.

It remains a mystery what might drive LSR J1835+3259’s auroras. On Earth, auroras are driven by winds of electrically charged particles streaming from the sun, but this brown dwarf does not have a stellar companion.

One possibility is that LSR J1835+3259’s auroras are driven by an Earth-size planet that generates strong currents in the brown dwarf’s magnetosphere as it barrels through its magnetic field, Hallinan said. Auroras on Jupiter are driven, in part, by its moon Io plowing through Jupiter’s magnetic field.

Another possibility is that electrically charged particles might rain down on the brown dwarf from above to drive the auroras. It remains uncertain where such particles might come from — perhaps interstellar gas and dust, or matter venting from a nearby volcanic planet, or plasma originally spewed upward from the brown dwarf itself, Hallinan said.

Hallinan and his colleagues have developed a new array of radio telescopes, the Owens Valley Long Wavelength Array in California, dedicated to detecting far-off auroras. “We’ve already confirmed aurorae for a few more objects,” Hallinan said. “Maybe 10 percent or higher of brown dwarfs may exhibit aurorae.”

Moreover, Hallinan suggested that it may be possible to detect auroras from exoplanets circling other stars — specifically, gas giants larger than Jupiter with powerful magnetic fields. “Extrasolar aurorae could help us measure how strong the magnetic fields of extrasolar planets are,” Hallinan said.

The scientists detail their findings in the July 30 issue of the journal Nature.

Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

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‘Most Earth-like planet ever discovered’


This video from the USA says about itself:

EXOPLANET Kepler-452b

23 July 2015

Kepler-452b, it is the smallest planet to date discovered orbiting in the habitable zone of a G2-type star, like our sun.

From NASA in the USA:

July 23, 2015

NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

NASA’s Kepler mission has confirmed the first near-Earth-size planet in the “habitable zone” around a sun-like star. This discovery and the introduction of 11 other new small habitable zone candidate planets mark another milestone in the journey to finding another “Earth.”

The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone — the area around a star where liquid water could pool on the surface of an orbiting planet — of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030.

“On the 20th anniversary year of the discovery that proved other suns host planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble the Earth and our Sun,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “This exciting result brings us one step closer to finding an Earth 2.0.”

Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. While its mass and composition are not yet determined, previous research suggests that planets the size of Kepler-452b have a good chance of being rocky.

While Kepler-452b is larger than Earth, its 385-day orbit is only 5 percent longer. The planet is 5 percent farther from its parent star Kepler-452 than Earth is from the Sun. Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger.

“We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment,” said Jon Jenkins, Kepler data analysis lead at NASA’s Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b. “It’s awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth. That’s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.”

To help confirm the finding and better determine the properties of the Kepler-452 system, the team conducted ground-based observations at the University of Texas at Austin’s McDonald Observatory, the Fred Lawrence Whipple Observatory on Mt. Hopkins, Arizona, and the W. M. Keck Observatory atop Mauna Kea in Hawaii. These measurements were key for the researchers to confirm the planetary nature of Kepler-452b, to refine the size and brightness of its host star and to better pin down the size of the planet and its orbit.

The Kepler-452 system is located 1,400 light-years away in the constellation Cygnus. The research paper reporting this finding has been accepted for publication in The Astronomical Journal.

In addition to confirming Kepler-452b, the Kepler team has increased the number of new exoplanet candidates by 521 from their analysis of observations conducted from May 2009 to May 2013, raising the number of planet candidates detected by the Kepler mission to 4,696. Candidates require follow-up observations and analysis to verify they are actual planets.

Twelve of the new planet candidates have diameters between one to two times that of Earth, and orbit in their star’s habitable zone. Of these, nine orbit stars that are similar to our sun in size and temperature.

“We’ve been able to fully automate our process of identifying planet candidates, which means we can finally assess every transit signal in the entire Kepler dataset quickly and uniformly,” said Jeff Coughlin, Kepler scientist at the SETI Institute in Mountain View, California, who led the analysis of a new candidate catalog. “This gives astronomers a statistically sound population of planet candidates to accurately determine the number of small, possibly rocky planets like Earth in our Milky Way galaxy.”

These findings, presented in the seventh Kepler Candidate Catalog, will be submitted for publication in the Astrophysical Journal. These findings are derived from data publicly available on the NASA Exoplanet Archive.

Scientists now are producing the last catalog based on the original Kepler mission’s four-year data set. The final analysis will be conducted using sophisticated software that is increasingly sensitive to the tiny telltale signatures of Earth-size planets.

Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

See also here.

IF ALIEN LIFE EXISTS, WE’RE ‘ON THE CUSP’ OF DISCOVERING IT At least, that’s according to Dr. John Grunsfeld, the physicist and former astronaut who heads up NASA’s Science Mission Directorate. [Jen Bendery, HuffPost]

We were wrong on dwarf planet Pluto, astronomers say


Dwarf planet Pluto

From daily The Independent in Britain:

New Horizons: Scientists admit they were completely wrong about ‘inert’ Pluto

Photos from the New Horizons spacecraft show 3,000m mountains and possible volcanoes

Ian Johnston

As Nasa’s New Horizons spacecraft took its last look at Pluto yesterday from nearly six million kilometres away, scientists were marvelling at how “very active” the dwarf planet is in contrast with previous theories that it was an inert ball of ice and rock.

Extraordinary photographs from the mission have shown vast plains, 3,000-metre mountains, possible volcanoes, rift valleys and other features suggesting it has a molten core and shifting tectonic plates.

Just like Earth. The absence of impact craters from meteorites on its plains, however, indicates they are geologically speaking quite young, perhaps 100 million years old, and that Pluto is probably geologically active. Similar signs have been seen on its moon, Charon.

Previously it had been thought that both must be inert lumps drifting through space. But Alan Stern, principal investigator of Nasa’s New Horizons mission, said that scientists had been “completely wrong about that”.

“They are very active. Pluto and Charon have been geologically active for billions of years, but we don’t know what the energy is that is driving it. It’s a puzzle,” he told The Sunday Times. “They have surface areas that have no craters. There must be craters unless they are young.

“We also see faultlines, scarps and other tectonic features such as rift valleys on both Pluto and Charon. It is unmistakable.”

One theory behind the movement on Pluto’s surface is that there is a radioactive heat source in its rocky core, thought to make up about 60 per cent of its mass.

The rest is mostly a thick layer of ice so cold that it behaves like stone. However, the hot core could be sending geysers of warm water shooting up to the surface.

Pluto has a layer of atmosphere, made up mainly of nitrogen, which extends about 1,600km above its surface.

However, this is gradually being stripped away by the solar wind, creating a “plasma tail” extending up to 109,000km. Scientists hope to work out how quickly this is happening, with more data expected in August. So far, New Horizons has sent a gigabit of information but another 49 gigabits are expected. “What we have now is scratching the surface. The best is yet to come,” Mr Stern said.

Read more: PLUTO BIGGER THAN WE THOUGHT

Pluto’s vast, craterless plains ‘exceed all expectations’ in latest image

WATCH HOW FAR WE’VE COME IN THREE-BILLION-MILE JOURNEY TO PLUTO

NEW HORIZONS IMAGES THROW OUT PREVIOUS UNDERSTANDING OF PLUTO

PLUTO’S MOON, HYDRA, SHOWN IN DETAIL FOR FIRST TIME EVER

Some of Pluto’s features have already been named informally, such as the Sputnik Plain, after the first spaceship, the Norgay Mountains, after Tenzing Norgay, the first person to climb Mount Everest along with Edmund Hillary, and the Tombaugh Region after Clyde Tombaugh, who discovered Pluto in 1930.

Other names used include Meng-p’o, the Buddhist goddess of forgetfulness; Vucub-Came and Hun-Came, heroic twins and death gods of the Mayan people of Central America; and Balrog, a monster from The Lord of the Rings.

The New Horizons mission enabled scientists to accurately measure Pluto for the first time and it appears to be the largest of the dwarf planets at 2,370km (1,473 miles) in diameter.

Early yesterday, New Horizons was 5.7 million km (about 3.5 million miles) beyond Pluto. “This will be our last look at the dark areas on Pluto’s surface. Bitter sweet!” Nasa’s New Horizons mission tweeted.

Dwarf planet Pluto, best ever photos


Close-up of mountains of Pluto

This NASA photo of today shows a close-up view of mountains on Pluto. There are no visible impact craters, NASA said, suggesting that the dwarf planet may be relatively young.

By David Freeman & Eliza Sankar-Gorton in the USA:

Dazzling New Pluto Photos Are The Best Ever Taken Of The Icy Dwarf Planet

07/15/2015 3:34 pm EDT Updated: 23 minutes ago

One day after its historic flyby of Pluto and almost a decade since its launch, NASA’s New Horizons space probe has delivered what we’ve all been waiting for: eye-popping photos of the dwarf planet and its moons.

(Scroll down to see the photos.)

NASA seemed to have trouble tamping down its excitement over the detailed images. “You ain’t seen nothing yet!” the space agency tweeted late last night.

They weren’t kidding–just have a look.

Snow on dwarf planet Pluto?


This video from the USA says about itself:

New Horizons reaches Pluto

14 July 2015

The NASA New Horizons spacecraft had its closest encounter with Pluto on Tuesday after a nine-a-half-year journey to the dwarf planet. Watch NASA’s live coverage here.

From Scientific American:

Is It Snowing on Pluto?

By Maria Temming

July 15, 2015

Plutophiles are abuzz over the New Horizons spacecraft’s observations of the object formerly known as the ninth planet. As the ship approached Pluto on July 13, it snapped the best shot of the dwarf planet yet, revealing previously unseen surface features that, according to NASA scientists, suggest Pluto is home to a rare weather phenomenon: snow.

Because Pluto is a frigid body with an icy surface, one might expect Pluto to host the occasional snowstorm. But cold temperatures and frozen materials do not a snowy planet make. In order to have frozen material fall from the sky, a planet needs either an atmosphere that can host snow clouds or volcanic eruptions that can launch freezable material high enough. It also needs a solid surface for that snow to land on, explains planetary scientist Bruce Betts of the Planetary Society. Few objects in the outer solar system meet these requirements. But Pluto, which has a thin nitrogen atmosphere with the potential for producing snow, might just be one of them.

When asked during a press conference if the new image confirms that it’s snowing on Pluto, Alan Stern, NASA’s principal investigator on the New Horizons mission, simply replied, “It sure looks that way.” A somewhat awkward silence ensued, during which the audience clearly thought he would elaborate. He didn’t, but New Horizons should confirm suspicions of snow soon enough. During New Horizons’ closest encounter with Pluto on July 14, the spacecraft was temporarily out of touch with Earth so that it could fo[c]us all its attention on collecting data, but over the next several months that data will start flooding back to NASA scientists. If it is snowing on Pluto, the dwarf planet joins a very exclusive club: snow of various weird kinds falls on only a handful of planets and moons across the solar system.

Mars rover launched


Planet Mars

On 26 November 2011, in the United States, the Mars Rover Curiosity has been launched, to investigate the red planet: here.

Pluto and its moon Charon photographed


The last image taken before the July 14 flyby by the New Horizons spacecraft, released by NASA July 14

From World Science in the USA:

New Pluto images released with historic flyby

July 14, 2015

Courtesy of NASA and World Science staff

NASA has re­leased new im­ages of Plu­to with a his­tor­ic fly­by this morn­ing of the agen­cy’s New Hori­zons space­craft, launched in 2006.

The Pluto image, taken shortly be­fore the fly­by, has a reso­lution of about 4 km per pix­el, the scien­tists said in a media brief­ing July 14. That’s about a thou­sand times more de­tailed than the best im­ages taken from near Earth.

A re­lat­ed im­age tak­en July 11 also shows Plu­to’s larg­est moon, Char­on. Col­or da­ta be­ing re­turned by the space­craft now will up­date these im­ages, bring­ing col­or con­trast in­to sharp­er fo­cus, ac­cord­ing to agen­cy sci­en­tists.

Agen­cy sci­en­tists al­so re­ported the dis­cov­ery of a sys­tem of chasms on Char­on, larg­er than the Grand Can­yon on Earth.

The closest approach was about 7,700 miles (about 12,400 km) and took place at 7:49 a.m., according to NASA scientists.

New Horizons is currently out of communication from Earth so that it can focus on Pluto, they added, but is expected will start releasing additional data this evening and in the coming days and months.

The flyby “completes the reconnaissance” of the solar system by spaceships, started with Mars 50 years ago, said Alan Stern of Southwest Research Institute, principal investigator for New Horizons, at the briefing.

Many more images will be “raining to the ground beginning tomorrow,” he added.

The images show Pluto and Charon as quite different, he added. “To my eye, these images show a much younger surface on Pluto, and a much older and more battered surface on Charon,” he remarked. This could be due to more active geology or atmospheric activity, changing the surface of Pluto, he said. “It sure looks” as though it snows, for example. But further images should help clarify this.

The piano-sized New Horizons craft zipped past Pluto at an estimated 30,800 miles (49,600 km) per hour.

In related findings, up­dat­ed mea­sure­ments ob­tained by New Hori­zons in­di­cate that Plu­to is 2,370 km (1,473 miles) wide, 18.5 per­cent the width of Earth. Mean­while Char­on is mea­sured as about half as wide as Pluto, or 1,208 km, about the size of Tex­as.

Pluto is a type of planet known as an “ice dwarf,” found in the Kuiper Belt region billions of miles from the sun. The Kuiper belt, a ring of icy rocks outside the orbit of Neptune, is the source of some comets and an object of astronomers’ interest in its own right, as it’s thought to contain ancient leftovers of the planet formation process.

Charon, Pluto's largest moon, in a NASA image released July 13

See also here.