Astronomers Discover a Potentially Habitable Nearby Super-Earth, Gliese 832 c

Gliese 832c is Best Habitable Candidate to Date

Artistic representation of the potentially habitable Super-Earth Gliese 832 c against a stellar nebula background. Credit: PHL @ UPR Arecibo, NASA Hubble, Stellarium.

Using data from HARPS-TERRA, the Planet Finder Spectrograph and the UCLES echelle spectrograph, astronomers have discovered a new potentially habitable Super-Earth around the nearby red-dwarf star Gliese 832.

An international team of astronomers, led by Robert A. Wittenmyer from UNSW Australia, report the discovery of a new potentially habitable Super-Earth around the nearby red-dwarf star Gliese 832, sixteen light years away. This star is already known to harbor a cold Jupiter-like planet, Gliese 832 b, discovered on 2009. The new planet, Gliese 832 c, was added to the Habitable Exoplanets Catalog along with a total of 23 objects of interest. The number of planets in the catalog has almost doubled this year alone.

Gliese 832 c has an orbital period of 36 days and a mass at least five times that of Earth’s (≥ 5.4 Earth masses). It receives about the same average energy as Earth does from the Sun. The planet might have Earth-like temperatures, albeit with large seasonal shifts, given a similar terrestrial atmosphere. A denser atmosphere, something expected for Super-Earths, could easily make this planet too hot for life and a “Super-Venus” instead.

Nearby Super Earth Gliese 832c

Artistic representation of the potentially habitable exoplanet Gliese 832 c as compared with Earth. Gliese 832 c is represented here as a temperate world covered in clouds. The relative size of the planet in the figure assumes a rocky composition but could be larger for a ice/gas composition. Credit: PHL @ UPR Arecibo.

The Earth Similarity Index (ESI) of Gliese 832 c (ESI = 0.81) is comparable to Gliese 667C c (ESI = 0.84) and Kepler-62 e (ESI = 0.83). This makes Gliese 832 c one of the top three most Earth-like planets according to the ESI (i.e. with respect to Earth’s stellar flux and mass) and the closest one to Earth of all three, a prime object for follow-up observations. However, other unknowns such as the bulk composition and atmosphere of the planet could make this world quite different to Earth and non-habitable.

So far, the two planets of Gliese 832 are a scaled-down version of our own Solar System, with an inner potentially Earth-like planet and an outer Jupiter-like giant planet. The giant planet may well played a similar dynamical role in the Gliese 832 system to that played by Jupiter in our Solar System. It will be interesting to know if any additional objects in the Gliese 832 system (e.g. planets and dust) follow this familiar Solar System configuration, but this architecture remains rare among the known exoplanet systems.

Orbital Analysis of Gliese 832 c

Orbital analysis of Gliese 832 c, a potentially habitable world around the nearby red-dwarf star Gliese 832. Gliese 832 c orbits near the inner edge of the conservative habitable zone. Its average equilibrium temperature (253 K) is similar to Earth (255 K) but with large shifts (up to 25K) due to its high eccentricity (assuming a similar 0.3 albedo). Credit: PHL @ UPR Arecibo.

Publication: Accepted for publication in ApJ

PDF Copy of the Study: GJ 832c: A super-earth in the habitable zone

Images: PHL @ UPR Arecibo, NASA Hubble, Stellarium; PHL @ UPR Arecibo

6 Comments on "Astronomers Discover a Potentially Habitable Nearby Super-Earth, Gliese 832 c"

  1. I’m a fan of science, astronomy and other related subjects.
    Why do you always get people excited about these news/new discoveries in the beginning of the article and blow it at the end by saying that life is not possible. First you say that it’s an exoplanet like Earth and then you start adding comments like “Oh it might be too hot, no wait it might be too cold, no wait it’s all gas or rocky, no wait it’s too close or too far from the host star. Why don’t mention this in the beginning of the article?
    Other than that your website it’s interesting. Thanks

    • That and the fact that it’s 5.4 earth masses. Doesn’t that mean it will be a little hard to walk on that planet?

      • Not necessarily. If the density is similar to earth then the radius of the planet is larger. The equation, I believe, is g=m/r^2

  2. I believe the objective is to find extraterrestrial life, not another Earth for us to live on. Life can exist in extreme environments and adapts to it’s environment very well. Finding life (not necessarily intelligent life) on another planet would be big news. It would change the way we see ourselves and our place in the universe. We’ve just begun to scratch the surface so be patient. These things take time and let’s face it funding for space exploration is not at the top of anyone’s list,unfortunately.

  3. Anyway, the University of Washington habitable zone calculator, based on Kopparapu et al. (2013) paper, puts Gliese 832 c outside the habitable zone, inward of the inner habitable zone – runaway greenhouse limit.
    The updated version of that same habitable zone calculator, using the Kopparapu et al. (2014) paper and featured on Ravi Kumar Kopparapu’s website, still puts the inner edge of the habitable zone out at 0.167 AU.
    The effective distance for Gliese 832 c is around 0.1617 AU and the average distance at 0.1656 AU.

  4. Sankaravelayudhan Nandakumar | May 26, 2015 at 6:59 pm | Reply

    I am interested to prove my theory of hologram towards genetic evolution of humanbeings that can be compared with that of our mother earth w ith sun as a solar source along with moon as another reflective mirror with other planetary reflections with reference to differentiable root locus diagram with movable genetic reference plane as operative in each 30 degrees with reference to movement of our solar.

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