The telescope opens the hunt for potentially habitable planets around the nearest stars that make up the star system Alpha Centauri and are only four light years away.

Numerous planets have been discovered in recent years. But most of them are quite far from Earth. “Astronomers have amazing technologies that allow us to find thousands of planets orbiting stars in the far reaches of our galaxy,” notes astronomer Peter Tuthill, of the University of Sydney. “But we hardly know anything about our own cosmic backyard.” For example, it is still unknown whether the stars closest to our solar system also harbor (habitable) planets. But that will soon change. Scientists have announced a new research project tonight: armed with a specially developed telescope, they will actively search for planets in Alpha Centauri.

About Alpha Centauri

Alpha Centauri is a star system located just four light-years from Earth and home to three stars. Two of them are sun-like and are designated Alpha Centauri A and B. The third star is a red dwarf and is known as Proxima Centauri. Researchers have previously discovered a planet (Proxima b) around this red dwarf star that appears to be in the so-called habitable zone and can therefore harbor liquid water – an important ingredient for life as we know it. Astronomers think it is not inconceivable that the other two sun-like stars also have planets. But evidence for this is lacking to date.

The two sun-like stars in Alpha Centauri. Image: NASA/ESA.

Technological Challenge

This is mainly due to the fact that the instruments with which scientists have previously discovered thousands of exoplanets at a much greater distance from Earth, are actually unsuitable for the search for planets closer to home. “The search for planets around the closest stars in the night sky is a huge technological challenge, even when those stars are very bright,” said Eduardo Bendek, of NASA’s Jet Propulsion Laboratory. “The signal we’re looking for requires very precise measurements,” adds engineer Pete Klupar.

With a new telescope, researchers expect that these measurements and therefore the discovery of nearby planets will become possible. “No one underestimates the challenge, but our innovative design harbors new tricks,” says Tuthill. “Our plan is to quickly and cheaply set up a mission that will deliver the first results by the middle of the decade.”

TOLIMAN

The mission already has a name: TOLIMAN. That stands for Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood, but is above all a reference to Alpha Centauri, which used to be called Toliman in Arabia. “Our TOLIMAN mission will launch a custom-built telescope into space that will measure the position of nearby stars in the sky with extreme precision. If a planet orbits such a star, it will pull on the star and its presence will be betrayed by a very small but measurable wobble of the star,” said Bendek.

That’s what the telescope that hunts for nearby planets should look like. Image: Sydney University.

The mission is led by the University of Sydney, but powered by Breakthrough Initiatives; an American organization that aims, among other things, to find evidence for (primitive) life on Earth-like planets in our cosmic backyard. Also NASAs Jet Propulsion Laboratory is involved in the mission.

High expectations

Expectations are high about what can be found around the stars in Alpha Centauri, as well as beyond. “If we look at the dozens of nearest stars, we expect to find a handful of Earth-like planets that are at the right distance from their parent star and can therefore harbor liquid water on their surfaces,” Klupar said. If the mission does indeed lead to the discovery of potentially habitable planets around nearby stars, that is really just the prelude to more, Tuthill emphasizes. “Getting to know our planetary neighbors is extremely important.” Because only when we know where potentially habitable planets are located in our cosmic backyard, can we also search for nearby aliens. In concrete terms, after discovering potentially habitable planets, astronomers will first focus on detecting and characterizing their atmospheres (this is slightly easier with nearby planets than with planets far away). While analyzing these extraterrestrial atmospheres, scientists will mainly look for gases that (can) indicate the presence of (primitive) life.

if it’s on Breakthrough Initiatives however, it does not stop at a remote analysis. The organization also wants to set up an unmanned mission to Alpha Centauri in the long term. The spacecraft should fly by Proxima b anyway, but the organization sincerely hopes that more planets in the triple star system will be discovered in the near future. Because since the probe is on its way to Alpha Centauri for about 50 years, it would be nice if there was more to see and explore than just Proxima b upon arrival.