Gliese 832c: Potentially Habitable Super-Earth Discovered 16 Light-Years Away

Jun 30, 2014

By Sci-News

 

Gliese 832, also known as HD 204961 or LHS 3685, is a M1.5 dwarf located in the constellation Grus, about 16 light-years from Earth. It has about half the mass and radius of the Sun.

This star is already known to harbor Gliese 832b, a cold Jupiter-like planet discovered in 2009.

“With an outer giant planet and an interior potentially rocky planet, this planetary system can be thought of as a miniature version of our Solar System,” said Prof Chris Tinney, an astronomer with the University of New South Wales and a co-author of the discovery paper accepted for publication in theAstrophysical Journal (arXiv.org pre-print).

The newly discovered exoplanet, labeled Gliese 832c, has an orbital period of 35.68 days, a mass 5.4 times that of Earth’s and receives about the same average energy as Earth does from the Sun.

Gliese 832c might have Earth-like temperatures, albeit with large seasonal shifts, given a similar terrestrial atmosphere.

“If the planet has a similar atmosphere to Earth it may be possible for life to survive, although seasonal shifts would be extreme,” Prof Tinney said.

A denser atmosphere, something expected for Super-Earths, could easily make this planet too hot for life and a Super-Venus instead.

8 comments on “Gliese 832c: Potentially Habitable Super-Earth Discovered 16 Light-Years Away

  • @OP- The newly discovered exoplanet, labeled Gliese 832c, has an orbital period of 35.68 days, a mass 5.4 times that of Earth’s and receives about the same average energy as Earth does from the Sun.

    With such a short year, and a close proximity to its star, it is probably tidally locked. Which could leave it with a day length of several Earth days, or even on face in permanent daylight and the other in permanent darkness.
    (http://en.wikipedia.org/wiki/Tidal_locking)
    Close binary stars throughout the universe are expected to be tidally locked with each other, and extrasolar planets that have been found to orbit their primaries extremely closely are also thought to be tidally locked to them.

    “If the planet has a similar atmosphere to Earth it may be possible for life to survive, although seasonal shifts would be extreme,” Prof Tinney said.

    If a tidally locked planet has an axial tilt, the light-dark cycle, would be seasonal.

    A denser atmosphere, something expected for Super-Earths, could easily make this planet too hot for life and a Super-Venus instead.

    If one side was in permanent darkness, the atmospheric weather patterns would indeed be strange.



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  • I think that the scientists studying this have been blinded by their desire to find an earth-like planet, by this description:

    “has an orbital period of 35.68 days, a mass 5.4 times that of Earth’s and receives about the same average energy as Earth does from the Sun.

    Gliese 832c might have Earth-like temperatures, albeit with large seasonal shifts”

    Whoever put this blurb together didn’t for a moment consider what that would be like: a year only 35 days long, with large seasonal shifts. So you’d have winter for one week at the beginning of the month, spring for one week, summer for one week, and fall for one week. Except for the fact that the atmosphere wouldn’t even have time to catch up to these seasonal changes, and you can pretty much expect that the climate would be the same year-round. Next, there’s the assumption that a planet 5 times the mass of Earth wouldn’t have a much thicker atmosphere, when that’s a near certainty. Add to that the fact that such a planet’s gravitational pull would also be 5 times that of earth, and you have a place where it’s almost certain that humans definitely wouldn’t be able to live, and the likelihood of anything more complicated than algae evolving is slim to none.

    To call this planet remotely habitable is wishful thinking at best, if not a pack of lies crafted to grab headlines.



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  • Ernie – Whoever put this blurb together didn’t for a moment consider what that would be like: a year only 35 days long, with large seasonal shifts. So you’d have winter for one week at the beginning of the month, spring for one week, summer for one week, and fall for one week.

    Unless the planet was tilted on an axis, it would have no seasons at all. Rotation is usually needed to maintain a stable axis, and a tidally locked planet would have minimal rotation.

    One of the problems in seeking exoplanets, is that those which are large and in orbits close to their stars, as the easiest to find.



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  • 6
    JoeCampanini says:

    Nowhere in the article did it mention humans Ernie, it just said habitable. They used to think it was impossible for life to evolve around a volcanic vent a couple of kilometers under the ocean… but guess what? And who would have guessed an ocean 100 km deep under the icy surface of Europa, a possible haven for life? Or is that also impossible? Don’t be so negative Ernie, be skeptical, but not negative.



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  • A3Kr0n Jul 1, 2014 at 3:31 pm

    Looks smogy.

    It’s only an artists impression. They don’t know what it looks like.

    @ link – Artistic representation of the potentially habitable exoplanet Gliese 832 c as compared with Earth. Image credit: PHL / UPR Arecibo.

    I think with likely tidal locking, and a probable denser atmosphere it does not look much like an Earth type planet.

    Also @link – “It will be interesting to know if any additional objects in the Gliese 832 system follow this familiar Solar System configuration, but this architecture remains rare among the known exoplanet systems,” the scientists said.

    It is however possible there are other more Earth-like planets in that system, which are yet to be discovered orbiting further out, where they are harder to find.

    In optimising searches, this link is helpful:- http://astro.unl.edu/naap/habitablezones/ghz.html



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  • Also, don’t forget that (assuming that the density of this planet is similar to that here), due to the higher radius, the surface gravity there will only be about 1.75 (5.4^(1/3)) times as high as on Earth.

    (More detailed explanation: The radius r of a planet is proportional to the cubic root of its volume, which is proportional to its density, and gravitational attraction F_g is inversely proportional to the square of the distance of the bodies involved. Since the gravity field generated by a sphere is equal to the gravity field generated by a point at the center of the same sphere with the same mass as the sphere, this means that gravitational attraction on the surface of a sphere is proportional to the inverse square of its radius. So, we can work out that F_g is proportional to r^(1/3) given a fixed density.)



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