Worlds next door: looking for habitable planets around Alpha Centauri
A simulated view of the Alpha Centauri binary through the diffractive pupil proposed for the TOLIMAN telescope. Source: Peter Tuthill
A mission to discover new planets potentially capable of sustaining life around Earth鈥檚 nearest neighbour, Alpha Centauri, was announced today.
The proposed telescope project will look for planets in the 鈥楪oldilocks鈥� zone around the star system just four light years away, where temperatures could allow for liquid surface water on rocky planets.
Work on the project began in April of this year. Scientists from the University of Sydney, in partnership with the in California, in Australia and , have named the project TOLIMAN, the Arabic-derived name for Alpha Centauri from antiquity.
鈥淥ur nearest stellar neighbours 鈥� the Alpha Centauri and Proxima Centauri systems 鈥� are turning out to be extraordinarily interesting,鈥� said Dr Pete Worden, Executive Director of the Breakthrough Initiatives. 鈥淭he TOLIMAN mission will be a huge step towards finding out if planets capable of supporting life exist there.鈥�
Project leader Professor Peter Tuthill from the at the University of Sydney is enthusiastic about this new window on the universe.
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Professor Peter Tuthill.
鈥淎stronomers have access to amazing technologies that allow us to find thousands of planets circling stars across vast reaches of the galaxy,鈥� he said. 鈥淵et we hardly know anything about our own celestial backyard.
鈥淚t is a modern problem to have; we are like net-savvy urbanites whose social media connections are global, but we don't know anyone living on our own block."
This blind spot in our local knowledge has important consequences, he said.
鈥淕etting to know our planetary neighbours is hugely important,鈥� Professor Tuthill said. 鈥淭hese next-door planets are the ones where we have the best prospects for finding and analysing atmospheres, surface chemistry and possibly even the fingerprints of a biosphere 鈥� the tentative signals of life.鈥�
Our most immediate neighbour, Alpha Centauri, is a triple star with two stars very like our Sun. Either or both may host temperate planets, while the third star 鈥� the red dwarf Proxima Centauri, is already believed to have one planet in a 鈥楪oldilocks orbit鈥�,聽.
Alpha Centauri is our nearest star system, best known in the Southern Hemisphere as the bottom of the two pointers to the Southern Cross. Image here in聽optical and x-ray spectra. Source: NASA
The project has received support from the Breakthrough Initiatives, a suite of scientific and technological programs engaged in the search for extraterrestrial life. The Initiatives were founded by Israeli science and technology investor and philanthropist Yuri Milner.
, Chief Engineer of聽, said: 鈥淭hese nearby planets are where humanity will take our first steps into interstellar space using high-speed, futuristic, robotic probes.
鈥淚f we consider the nearest few dozen stars, we expect a handful of rocky planets like Earth orbiting at the right distance for liquid surface water to be possible.鈥�
Saber Astronautics received $788,000 from the Australian Government鈥檚聽聽grant, which will support the TOLIMAN mission.
The company, which operates in Australia and the United States, will provide spaceflight mission operations support, including satellite communications and command, space traffic management and a range of other flight services to download data from the satellite.
鈥淪aber is a critical part of the mission,鈥� Professor Tuthill said.
Dr Jason Held, CEO of Saber Astronautics, said: 鈥淭OLIMAN is a mission that Australia should be very proud of 鈥� it is an exciting, bleeding-edge space telescope supplied by an exceptional international collaboration. It will be a joy to fly this bird.鈥�
Precision measurement
, a member of the team from NASA鈥檚 Jet Propulsion Laboratory, said: 鈥淓ven for the very nearest bright stars in the night sky, finding planets is a huge technological challenge.
"Our TOLIMAN mission will launch a custom-designed space telescope that makes extremely fine measurements of the position of the star in the sky. If there is a planet orbiting the star, it will tug on the star betraying a tiny, but measurable, wobble."
Most of the thousands of known planets outside the solar system, called exoplanets, have been discovered using space telescopes such as NASA鈥檚 Kepler and TESS missions. Finding exoplanets close to home will take more finely tuned instruments, which is where the TOLIMAN mission comes in.
Mr Klupar said: "The signal we are looking for requires a real leap in precision measurement."
Professor Tuthill said: "Nobody is underestimating the challenge, but our innovative design incorporates new tricks. Our plan is for an agile, low-cost mission that delivers results by about the middle of the decade.鈥�
TOLIMAN stands for Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood, indicating the new approach to nearby exoplanet exploration and discovery.
Central to the mission is the deployment of a new type of telescope that uses a diffractive pupil lense. This mirror spreads starlight captured from nearby stars into a complex flower-like pattern that, paradoxically, makes it easier to detect perturbances of star movements that are the tell-tale signs of orbiting planets.
Proposed design of the TOLIMAN telescope.
Telescope design: The聽聽with a candidate telescope mirror pattern known as a聽diffractive pupil. Rather than concentrating the starlight into a tight focused beam as is usually done for optical systems, TOLIMAN has a strongly featured pattern, spreading starlight into a complex flower pattern that, paradoxically, makes it easier to register the fine detail required in the measurement to detect the small wobbles a planet would make in the star鈥檚 motion.
Declaration
The project has received seed funding from the Breakthrough Initiatives and funding from the Australian Government鈥檚 International Space Investment Expand Capability Grants program.