Our nearest neighbor, Alpha Centauri, is 4.37 light-years from Earth, which is super close from a cosmological perspective but achingly far from a human point of view. A new telescope promises to bring this intriguing star system, and any habitable planets it holds, into closer view.
The new mission, called TOLIMAN, was announced today in a press release. TOLIMAN is the ancient Arabic name for Alpha Centauri—the closest star system to Earth—but it’s also an acronym for Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood. Once in space, astronomers will use the orbital observatory to search for potentially habitable exoplanets around Alpha Centauri.
The international collaboration includes teams from the University of Sydney, Breakthrough Initiatives, Saber Astronautics, and NASA’s Jet Propulsion Laboratory. Peter Tuthill from the Sydney Institute for Astronomy at the University of Sydney will lead the project.
We’re quite fortunate to have such an intriguing next-door neighbor. Alpha Centauri is a triple star system consisting of two Sun-like stars, named Alpha Centauri A and Alpha Centauri B, and a red dwarf known as Proxima Centauri.
Two exoplanets are known to orbit Proxima Centauri: an Earth-sized planet parked inside the habitable zone (i.e. that sweet spot within which liquid water is stable at the surface) and a super-Earth located farther out. Alpha Centauri A is suspected to host a Neptune-sized exoplanet, but astronomers aren’t entirely certain. An exoplanet has yet to be discovered in orbit around Alpha Centauri B. Other exoplanets are likely still awaiting detection—and that’s where TOLIMAN comes in.
“Our nearest stellar neighbours—the Alpha Centauri and Proxima Centauri systems—are turning out to be extraordinarily interesting,” Pete Worden, executive director of Breakthrough Initiatives, said in the press release. “The TOLIMAN mission will be a huge step towards finding out if planets capable of supporting life exist there.”
Breakthrough Initiatives, founded by billionaire Yuri Milner, provided seed funding for the project, as did the Australian government through its International Space Investment Expand Capability Grants program. Saber Astronautics, the recipient of AUD$788,00 (USD$573,300) from the Australian government, will provide spaceflight mission operations support, including space traffic management and satellite communications. The firm has facilities in both Australia and the United States.
Jason Held, CEO of Saber Astronautics, described TOLIMAN in the press release as “an exciting, bleeding-edge space telescope,” one that will be “supplied by an exceptional international collaboration.” To which he added: “It will be a joy to fly this bird.”
TOLIMAN will be custom-tailored for the mission, and its strong suit will be in making extremely fine measurements of the positions of the stars. A key feature of the new telescope is a “diffractive pupil lens.” By dispersing stellar light into flower-like patterns, the lens will make it easier for astronomers to spot wobbles caused by orbiting exoplanets. Once an exoplanet is detected, more specialized telescopes can be recruited to search for potential biosignatures in the atmosphere or surface. The telescope is expected to reach orbit in 2023, as Centauri Dreams reports.
In 2019, scientists with Breakthrough Listen, one of several projects supported by Breakthrough Initiatives, identified a candidate signal coming from Proxima Centauri, in what was the first and so far only potential alien technosignature detected by the group. Subsequent research found the signal to be of human origin, ruling out an alien civilization as the source.