How Will the James Webb Telescope Unlock the Secrets of SPECULOOS-3 b?
Astronomers have made a significant discovery: an Earth-sized exoplanet, named SPECULOOS-3 b, located approximately 55 light-years from Earth. This newfound planet, though far too hostile for life as we know it, presents a unique opportunity for scientists to study the geology of a planet beyond our solar system.
SPECULOOS-3 b orbits its host star, a red dwarf about the size of Jupiter, every 17 hours. The planet is tidally locked, meaning one side perpetually faces the star while the other side remains in eternal darkness. This results in extreme conditions, with the planet being constantly bombarded by radiation from its 7 billion-year-old star. Consequently, any atmosphere that might have existed on SPECULOOS-3 b has long since been stripped away, leaving it a barren, rocky world.
Lead author Michaël Gillon, an astronomer at the University of Liège in Belgium, noted that the intense radiation and lack of an atmosphere make it impossible for life to emerge or sustain large amounts of liquid water on the planet’s surface. “Life as we know it could not emerge on the surface of the planet — atmosphere or not,” Gillon told Live Science. He likened SPECULOOS-3 b to Mercury, emphasizing its bare, rocky nature.
Despite its inhospitable environment, SPECULOOS-3 b’s proximity to Earth allows for detailed follow-up studies. Astronomers are particularly interested in using the James Webb Space Telescope (JWST) to examine the planet’s chemical composition, which could reveal whether it was ever geologically active. Such observations might confirm the presence of ancient volcanic activity, providing insights into the formation of rocky planets around ultracool dwarf stars and their potential to support life under different conditions.
The discovery was made using the SPECULOOS (Search for Planets Eclipsing Ultra-Cool Stars) network of telescopes, which has been operational since 2011. This network, comprising six telescopes spread across Chile, the Canary Islands, and Mexico, focuses on detecting planets around ultracool dwarf stars. These stars, significantly smaller and cooler than our Sun, burn their fuel slowly, resulting in extraordinarily long lifespans of up to 100 billion years. This longevity offers an extended window for life to emerge on orbiting planets.
Study co-author Amaury Triaud, a professor of exoplanetology at the University of Birmingham in England, highlighted the significance of these stars’ long lifespans. “They are expected to be the last stars still shining in the universe,” Triaud said. Despite their faintness, which makes them challenging to study, their extended lifetimes provide favorable conditions for the development of life.
The discovery of SPECULOOS-3 b involved continuous observation of the host star’s light for five nights in 2021 using a SPECULOOS robotic telescope in Mexico. The telltale dips in the star’s light indicated the presence of the planet, a finding that was confirmed a year later.
Co-author Benjamin Rackham, a research scientist at MIT, described the planet’s harsh conditions. “If there’s no atmosphere, there would be no blue sky or clouds — it would just be dark, like on the surface of the moon,” Rackham said. The star would appear as a large, purplish-red, flaring object in the sky, about 18 times the size of our Sun.
SPECULOOS-3 b is the ninth planet discovered by the SPECULOOS project. The team expects to identify many more in the coming years, with these discoveries providing excellent targets for the JWST. Previous findings by the project, including the well-known TRAPPIST-1 system, have already expanded our understanding of potentially habitable exoplanets. The ongoing research promises to uncover further insights into the formation and characteristics of rocky planets in distant star systems.
As reported by Live Science in their recent article
