Closest Star To The Sun May Be Hosting A Hidden Super-Earth

  • Researchers find evidence of the second exoplanet orbiting our nearest stellar neighbor Proxima Centauri. 
  • Dubbed Proxima c, it may be six times as massive as Earth. 
  • It is estimated to be much colder than Earth and unlikely to be habitable.

For years astronomers have been observing our nearest stellar neighbor Proxima Centauri with different methods to find its planetary companions. It is a small, low-mass star located 4.243 light-years away from Earth in the southern constellation of Centaurus.

In 2016, the European Southern Observatory discovered a planet orbiting in the habitable zone of the Proxima Centauri. It is named Proxima Centauri b, and it is the closest known exoplanet to our Solar System.

Now an international team of researchers has discovered what they believe could be yet another exoplanet orbiting the star. Dubbed Proxima c, it may be a super-Earth with a mass higher than Earth but lower than ice giants Neptune and Uranus.

They Analyzed 17 Years’ Worth Of Data

Proxima c is estimated to be six times as massive as Earth. It is expected to orbit its host star at a distance of 139 million miles, with an orbital period of 5.2 years.

In contrast, Proxima b orbits Proxima Centauri at a distance of 4.6 million miles with an orbital period of 11.2 Earth days.

Reference: Science Advances | DOI:10.1126/sciadv.aax7467 | Scientific American 

Because of the large distance from its host star, Proxima c is much colder than Earth and unlikely to be habitable. It could be an extremely frigid world: temperatures on this planet drop as low as -233 degrees Celsius.

Proxima CThe green region is a habitable zone of Proxima Centauri | Image credit: YouTube 

More follow-up is needed to confirm the existence of Proxima c. In this study, researchers have shown that the existence of this exoplanet can be ascertained, and its precise mass can be evaluated by merging Gaia astrometry and radial velocities.

The conclusion of the study is supported by the analysis of spectroscopic activity diagnostics. If the existence of Proxima c does get confirmed, it may help researchers better understand the formation process of low-mass planets around small stars.

Usually, exoplanets like these are believed to form near the habitable zone of stars. However, Proxima c’s orbit lies far beyond this zone.

Read: 15 Closest Stars To Earth 

The findings offer opportunities for further observations of the planetary system of our closest star (other than the Sun), especially by direct imaging.

Written by
Varun Kumar

Varun Kumar is a professional science and technology journalist and a big fan of AI, machines, and space exploration. He received a Master's degree in computer science from Indraprastha University. To find out about his latest projects, feel free to directly email him at [email protected] 

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