GJ 1132b

An Atmosphere Has Been Detected Around an Earth-Like Exoplanet for the First Time

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Astronomers have detected an atmosphere around an Earth-like exoplanet called Gliese 1132b (GJ 1132b for short), which is located around 39 light-years away in the constellation Vela.

This is the first time atmosphere has ever been detected around a planet with a mass and radius so similar to Earth’s, and that makes it a hugely promising (and exciting) target for researchers searching for signs of extraterrestrial life.

 

“While this is not the detection of life on another planet, it’s an important step in the right direction: the detection of an atmosphere around the super-Earth GJ 1132b marks the first time that an atmosphere has been detected around an Earth-like planet other than Earth itself,” said lead researcher John Southworthfrom Keele University in the UK.

There’s still a lot to learn about GJ 1132b’s atmosphere, but early observations suggest it could be a “‘water world’ with an atmosphere of hot steam” – AKA, a pretty awesome place to go looking for life.

So far, we know that GJ 1132b has a mass about 1.6 times that of Earth’s, and has roughly 1.4 times its radius – which in terms of exoplanets makes it remarkably similar to our home planet.

But as with all exoplanet discoveries, the researchers are quick to remind the public that the observations to date still really don’t give us much insight into how similar GJ 1132b could be to Earth – or how habitable.

Some bad news upfront is it has an estimated surface temperature of 370 degrees Celsius (698 degrees Fahrenheit), which makes it unlikely that it could host life like us.

And let’s not forget that we’ve recently been burned by the detection of the TRAPPIST-1 ‘sister solar system’ and neighbouring Earth-like planet Proxima b, both of which are unlikely to be the friendly places for life we first thought they were.

 But none of those planets had ever gotten as far as having an atmosphere detected, so GJ 1132b is already doing pretty well in terms of a spot that could potentially host life.

Right now, the top strategy for astronomers in the search for life on another planet is to detect the chemical composition of that planet’s atmosphere, looking for certain chemical imbalances that could hint at the presence of living organisms. For example, on Earth, the large amount of oxygen in our atmosphere is that ‘smoking gun’.

We’re a long way off having that much insight into GJ 1132b, but the fact that we’ve detected its atmosphere at all is a good first step.

The planet orbits the not-too-distant red dwarf star Gliese 1132, which Southworth and his team studied using the ESO/MPG telescope in Chile.

They measured the slight dip in brightness across seven wavelengths of light as GJ1132b passed in front of its host star every 1.6 Earth days, in order to get a better idea of the size and composition of the planet.

They were surprised to find that the planet appeared larger when observed in one type of infrared wavelength of light, which suggests that the planet has an atmosphere that’s opaque to these wavelengths.

The team went on to model different possible versions of this atmosphere, and found that an atmosphere rich in water and methane could explain what they were seeing.

Prior to this, the only exoplanets that researchers have detected atmospheres around were planets that were more than eight times more massive than Earth, and gas giants similar to Jupiter.

“With this research, we have taken the first tentative step into studying the atmospheres of smaller, Earth-like, planets,” said Southworth. “The planet is significantly hotter and a bit larger than Earth, so one possibility is that it is a ‘water world’ with an atmosphere of hot steam.”

The type of star GJ 1132b is orbiting also makes the planet of particular interest – its host star is a low-mass red dwarf, which are incredibly common throughout the Universe and are frequently found to host small, Earth-like planets.

But they’ve also been shown to be particularly active, often blasting huge solar flares out at their surrounding planets – something previous research has suggested would evaporate any traces of a planet’s atmosphere.

But the new discovery suggests that an atmosphere is possible of enduring this bombardment for billions of years without being destroyed – which opens up the possibility that thousands more planets orbiting low-mass stars could potentially harbour atmospheres.

“Given the huge number of very low-mass stars and planets, this could mean that the conditions suitable for life are common in the Universe,” a press release explains.

We still have a lot to learn about GJ 1132b, and hopefully we’ll have some more answers soon – the new discovery makes it one of the highest-priority targets to be studied by instruments such as the Hubble Space Telescope, the Very Large Telescope, and the James Webb Space Telescope, which is scheduled to launch in 2018.

Source:sciencealert.com

Earth-like world could be ‘most important planet found outside solar system’ | Science | The Guardian

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GJ 1132b is close enough for telescopes to observe any atmosphere it might have, which could help scientists spot signs of life on other planets in the future

In this artist’s conception GJ 1132b, a rocky planet very similar to Earth in size and mass, circles a red dwarf star.
In this artist’s conception GJ 1132b, a rocky planet very similar to Earth in size and mass, circles a red dwarf star.

A rocky Earth-sized planet that circles a small, nearby star could be the most important world ever found beyond the solar system, astronomers say.

The planet lies in the constellation of Vela in the southern sky and is close enough for telescopes to observe any atmosphere it has, a procedure that could help spot life on other planets in the future.

Named GJ 1132b, the alien world is about 16% larger than Earth, and at 39 light years distant, is three times closer than any other Earth-sized rocky planet yet found around another star. At that distance, it is hoped that telescopes will be able to make out the chemistry of its atmosphere, the speed of its winds and the colours of its sunsets.

Astronomers spotted the planet as it moved across the face of a red dwarf star only a fifth the size of the sun. Though much cooler and fainter than the sun, GJ 1132b orbits so close to its star that surface temperatures reach 260C.

The searing temperatures are too hot for the surface to retain liquid water, making it inhospitable to life, but not so hot as to burn off any atmosphere that formed on the planet.

“If this planet still has an atmosphere, then we might find other, cooler planets that also have atmospheres and orbit small stars. We can then imagine interrogating the atmospheres for molecules that come from life,” said Zachory Berta-Thompson at the MIT’s Kavli Institute for Astrophysics and Space Research.

This time-lapse video shows MEarth-South discovering the planet GJ 1132b. Credit: Jonathan Irwin

Researchers used the MEarth-South array, a group of eight 40cm robotic telescopes at the Cerro-Tololo Inter-American Observatory in Chile, to detect the planet. As it whipped around its star, completing an orbit every 1.6 days, it produced a faint 0.3% dip in the starlight picked up by the telescopes, according to a report in Nature.

The planet is tidally locked to its star, much as the moon is to Earth, and has one face in permanent daylight, the other in darkness. Given the world’s size and mass, researchers suspect it is rocky, like the inner planets of our solar system. It orbits 1.4m miles from its star, far closer than Mercury, which is never less than 36m miles from the sun.

Because the red dwarf is so small, and the planet is on such a close orbit, astronomers should find it fairly easy to detect and study any atmosphere the world has. The team has already requested time on the Hubble and Spitzer space telescopes to observe the planet in more detail.

Drake Deming, an astronomer at the University of Maryland, said GJ 1132b was “arguably the most important planet ever found outside the solar system”. Its proximity and orbit around a red dwarf will allow astronomers to study the planet with unprecedented fidelity. “It’s nearby, it’s Earth-like, and its star won’t interfere,” Drake said.

The planet will become a prime target for future missions too, including the James Webb Space Telescope, which is expected to launch in 2018, and the Giant Magellan Telescope, which is due to start operations in Chile in 2025.

The discovery came as scientists announced they had found the most distant object in the solar system, a frozen body that lies more than 100 times farther from the Sun than Earth does. The object lies beyond the edge of the Kuiper belt, home to the dwarf planet Pluto, and into the realm of space dominated by the so-called Oort cloud, a vast shell of icy objects where comets such as Hale-Bopp are thought to have formed.

Spotted from the Subaru telescope on Mauna Kea in Hawaii, the distant object is at least 500km across, but has not been tracked long enough to work out the full path of its orbit.