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Proxima Centauri may host Earth-like planet

Artist’s impression of a sunset on an exoplanet around Proxima Centauri.

Artist’s impression of a sunset seen from the surface of an Earth-like exoplanet in a three-star system. Image Credit: ESO / L. Calçada

A rocky, Earth-like planet may be orbiting Proxima Centauri, the star closest to the Sun, according to a report published in the German weekly newspaper Der Spiegel.

Proxima Centauri is a red dwarf, low-mass star approximately 4.25 light-years away, part of the three-star Centaurus system, along with companions Alpha Centauri A and Alpha Centauri B.

Artist’s impression of a hypothetical planet around Alpha Centauri B near Proxima Centauri.

Artist’s impression of a hypothetical planet orbiting the star Alpha Centauri B. Image Credit: ESO / L. Calçada / Nick Risinger

The star was discovered just over 100 years ago in 1915 by Scottish astronomer Robert Innes and is about 0.12 light-years closer to Earth than its two companions.

According to Der Spiegel‘s announcement, which is based on information from an anonymous source who is supposedly part of the discovery team, the newly-found planet is Earth-like and is located within Proxima Centauri’s habitable zone, where liquid water can exist on the surface, making life as we know it possible.

It was discovered by astronomers using the European Southern Observatory’s (ESO) La Silla Observatory reflecting telescope.

A formal announcement of the finding will be made by the ESO in late August, the anonymous source reportedly said.

In 2012, astronomers at La Silla Observatory announced the discovery of Alpha Centauri Bb, billed as the nearest exoplanet to Earth. However, the existence of that planet was later called into question and its discovery attributed to an artifact in the observation data.

Unlike the 2012 finding, this one is real and was found through intense observation, the anonymous source stated in the article.

“Finding small celestial bodies is a lot of hard work. We are moving at the technically feasible limit of measurement,” the source said.

A laser sail propelled toward Proxima Centauri.

Rendition of a laser propelled sail. Image Credit: A. Mann

ESO spokesman Richard Hook declined to comment when asked about the discovery.

To date, NASA’s Kepler mission has discovered more than four thousand exoplanet candidates, whose statuses still await confirmation.

About 216 of these planet candidates are rocky worlds located in their stars’ habitable zones.

These potential Earth-like planets were subsequently reviewed by an international team of astronomers, who narrowed the list of those most likely to support life down to 20 worlds.

All 20 are hundreds or thousands of light-years from Earth, putting them out of reach for any possible robotic probes.

This would not be the case for an exoplanet just 4.25 light-years away, the article noted.

“The still nameless planet is believed to be Earth-like and orbits at a distance to Proxima Centauri that could allow it to have liquid water on its surface – an important requirement for the emergence of life. Never before have scientists discovered a second Earth that is so close by,” the source stated.

A DEEP laser-sail propelled toward Proxima Centauri.

Laser propulsion. Image Credit: Q. Zhang

Proxima Centauri may be the closest star to Earth, but its distance is still 271,000 times that of the Earth to the Sun, meaning it cannot be reached with today’s chemical rocket technology.

Plans to send robotic probes to Alpha Centauri via newer technology to search for life are already in the works.

Project Starshot, part of the Breakthrough Initiatives program founded by Russian billionaire Yuri Milner, aims to send a nanocraft powered by laser sails to Alpha Centauri to search for intelligent life.

It is backed by Stephen Hawking and Mark Zuckerberg, founder and CEO of Facebook.

Scientists with Project Starshot anticipate the nanocraft flying at 20 percent the speed of light. At that rate, the probe would reach Alpha Centauri, which is 4.37 light-years away, in just 20 years.

Changing its destination to the closer Proxima Centauri would reduce that travel time.

NASA’s Directed Energy for Relativistic Interstellar Missions (DEEP-IN) seeks to construct “wafer sats” that weigh a gram or less for interstellar travel to the closest stars. Using directed energy propulsion, the tiny probes, which would include sensors, optical systems, and integrated optical communications, would be capable of traveling at 25 percent the speed of light.


Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.

Reader Comments

It should be remembered that this is just a rumor at this stage. While I think it is highly likely that the rumor refers to an Earth-size planet has been discovered as a result of the ESO-led Pale Red Dot campaign which wrapped up its observations this past April, claims about this world’s potential habitability (i.e. its being “Earth-like”) need to be taken with a HUGE grain of salt at this stage. Even ignoring the fact that the term “Earth-like” has been used to describe planets that have more in common with Venus, far too often the media (and sometimes even exoplanet discovery teams) overhypes the potential habitability of newly discovered exoplanets. We will need to wait for the peer-reviewed discovery paper to be officially published later this month and get an independent assessment of this world from unbiased source.

A full description of what searches for exoplanets around Proxima Centauri have found (or more precisely, not found)is described here:

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