The hunt for Earth-like planets continues
16 March 2020
University of Birmingham researchers join the search for Earth-like planets with the commissioning of a new telescope.
Part of the SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) project, the Ganymede telescope is one member of a constellation of telescopes located in various parts of the world and dedicated to seeking out potentially habitable Earth-sized planets.
The Ganymede telescope is one of four SPECULOOS telescopes that make up the SPECULOOS-South Observatory.
SPECULOOS’ mission is to investigate planets orbiting ultra-cool dwarfs, a category that includes the smallest stars as well as brown dwarfs. Brown dwarfs are ‘sub-stellar’ objects that sit in between the largest gas planets and the smallest stars. Ultra-cool dwarfs have small sizes, which enables astronomers to distinguish small planets passing in front of them – helping to detect Earth-like planets.
The four telescopes in Chile, named Io, Europa, Ganymede and Callisto (after the largest moons orbiting Jupiter), started operation in January 2019. The instruments operate robotically, have mirrors that are 1m in diameter, and particularly sensitive cameras, capable of detecting the kind of light emitted by ultra-cool dwarfs.
The SPECULOOS telescopes are looking for exoplanets using the transit method, in which planets are detected as they pass in front of their parent star. This partial eclipse causes a dimming of the star, which can be detected by the instruments.
Over the next 10 years of its operation, researchers expect the telescopes will be able to survey around 1,400 stars, leading to the detection of around 20 planetary systems that they hope will contain several planets with masses and temperatures similar to the Earth.
The team has already discovered a seven-planet system a few years ago, called TRAPPIST-1, during a pilot run of the SPECULOOS survey.
Once the planets are identified, the team will turn to larger telescopes like the upcoming James Webb Space Telescope, or Europe’s Extremely Large Telescope, to seek signs of active biology by measuring the chemical composition and chemical balance of the planets’ atmospheres.
Dr Amaury Triaud, who is leading the Birmingham team, said: “This is pure exploration. Although we hope one day to detect signs of life, we currently have no idea whether these planets are capable of hosting some. That is because the only example we know of so far is right here on Earth, and we do not know how representative the conditions of Earth are.
“The stars SPECULOOS is monitoring are the most numerous in the universe, and they seem to host more Earth-sized planets than stars like our Sun do, so there could be a huge number of planets for us to find and study.
“The planets we will discover will be the easiest Earth-like planets to study. What is really interesting, though, is that – even in the case that none of these planets turns out to have atmospheres hospitable to life – our investigations will still tell us some crucial information about how often biology happens in the cosmos and under which conditions.”
The instruments operated by SPECULOOS-South in Chile are also part of an international observatory network, which includes a SPECULOOS-North telescope in Tenerife, the SAINT-EX telescope in Mexico and the TRAPPIST telescopes in Chile and Morocco. The SPECULOOS project is a collaboration between the University of Birmingham, the University of Liège, the University of Cambridge, MIT, the University of Bern and the Institute of Astrophysics of the Canaries.