4 mins read 23 Nov 2021

Looking for Habitable Planets in our Stellar Neighbourhood

A new mission to discover Earth-like planets potentially capable of sustaining life around Alpha Centauri has been announced.

Simulated View of Alpha Centauri using TOLIMAN. Credit: University of Sydney.

A proposed telescope project will look to Earth’s closest stellar neighbour - Alpha Centauri - for planets orbiting in the ‘Goldilocks zone’. Temperatures on these planets may allow for liquid water on a rocky surface, creating potentially habitable planets. Alpha Centauri is a triple star with two of the stars (Alpha Centauri A and Alpha Centauri B) being very like our own sun, and the red dwarf Proxima Centauri which is believed to have one exoplanet in the ‘Goldilocks zone’. 

“Astronomers have access to amazing technologies that allow us to find thousands of planets circling stars across vast reaches of the galaxy,” said the project leader Professor Peter Tuthill from the University of Sydney’s Sydney Institute for Astronomy .“Yet we hardly know anything about our own celestial backyard.”

“It 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."

“Getting to know our planetary neighbours is hugely important,” Professor Tuthill said. “These 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 – the tentative signals of life.”

The Alpha Centauri system as viewed in optical and x-ray spectra. Credit: University of Sydney.

Work on the project began in April this year and is a collaboration between scientists from the University of Sydney, Breakthrough Initiatives, Saber Astronautics, and NASA’s Jet Propulsion Laboratory.

“Our nearest stellar neighbours - the Alpha Centauri and Proxima Centauri systems - are turning out to be extraordinarily interesting,” said Dr Pete Worden, the Executive Director of the Breakthrough Initiatives. “The TOLIMAN mission will be a huge step towards finding out if planets capable of supporting life exist there.” 

The project is named TOLIMAN after the Arabic-derived name for Alpha Centauri from antiquity. TOLIMAN stands for Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood.

The telescope will detect slight wobbles in the star caused by gravity from orbiting planets. The telescope will use a diffractive pupil lense that scatters light in a flower-like pattern, paradoxically, making it easier to detect changes of star movements, indicating orbiting planets.

"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," said Dr Eduardo Bendek, a member of NASA’s JPL.

The proposed design for the TOLIMAN telescope. Credit: University of Sydney.

The majority of the thousands of exoplanets discovered outside our Solar system have been discovered using NASA’s Kelper and TESS missions. To find exoplanets closer to home requires much more finely tuned instrumentation, which is where the TOLIMAN mission comes in. 

"The signal we are looking for requires a real leap in precision measurement," said Pete Klupar, Chief Engineer of Breakthrough Watch.

"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,” said Professor Peter Tuthill.

The Australian company Saber Astronautics received $788,000 from the Australian Government’s International Space Investment: Expand Capability grant scheme. Saber provides 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.

“Saber is a critical part of the mission,” Professor Tuthill said.

“TOLIMAN is a mission that Australia should be very proud of – it is an exciting, bleeding-edge space telescope supplied by an exceptional international collaboration. It will be a joy to fly this bird,” said Dr Jason Held, CEO of Saber Astronautics.

Breakthrough Initiatives is a California based suite of science programs focused on finding extraterrestrial life. The Initiatives were founded by Israeli science and technology investor and philanthropist Yuri Milner.

“These nearby planets are where humanity will take our first steps into interstellar space using high-speed, futuristic, robotic probes,” said Mr Klupar.