What To Know
- A team of researchers led by scientists from the EXOTIC Laboratory of the University of Liège, Belgium, in collaboration with MIT and the Institute of Astrophysics of Andalusia, has just made an astonishing discovery in the field of astrophysics.
- The detection of WASP-193b was made possible thanks to the Wide Angle Search for Planets (WASP), an international project that uses two robotic observatories to monitor the brightness of stars.
- The mechanisms usually invoked to explain the evolution of planetary atmospheres, such as the escape of gas or collisions with other celestial objects, seem in fact insufficient to explain the magnitude of the expansion observed in WASP-193b.
A team of researchers led by scientists from the EXOTIC Laboratory of the University of Liège, Belgium, in collaboration with MIT and the Institute of Astrophysics of Andalusia, has just made an astonishing discovery in the field of astrophysics: the planet WASP-193b, whose density is so low that it is compared to cotton candy.
An ultra-soft world
Located at a distance of 1,200 light years from Earth, this new giant planet orbits a star similar to the Sun. What makes it particularly remarkable is its extraordinarily low density, comparable to that of cotton candy. Indeed, although WASP-193b is around 50% larger that Jupitershe is seven times less massivewhich places it among the least dense planets ever discovered. Its extremely low density makes it a real anomaly among the more than five thousand exoplanets discovered to date.“, explains Khalid Barkaoui, postdoctoral researcher at the EXOTIC Laboratory of the University of Liège. The detection of WASP-193b was made possible thanks to the Wide Angle Search for Planets (WASP), an international project that uses two robotic observatories to monitor the brightness of stars. The data collected revealed periodic transits of the star WASP-193, indicating the presence of a planet orbiting it. To confirm the discovery and learn more about this enigmatic planet, the researchers used the TRAPPIST-South and SPECULOOS-South observatories in Chile to measure the planetary signal in different wavelengths. In addition, spectroscopic observations made by the HARPS and CORALIE spectrographs made it possible to determine the mass of WASP-193b. The results were astonishing: the density of the planet was extremely low, approximately 0.059 grams per cubic centimeter, compared to 1.33 grams per cubic centimeter for Jupiter and 5.51 grams per cubic centimeter for Earth. Julien de Wit, professor at MIT, comments: ” The planet is so light that it’s hard to imagine a solid-state analog. The reason it’s similar to cotton candy is that both are mostly air. So this planet is basically super fluffy.. »
Illustration of Kelt-11b, another known cotton candy planet. Credits: W. ROBINSON / LEHIGH UNI
A planet that questions
Researchers suspect that WASP-193b is primarily consisting of hydrogen and helium, forming an extremely bloated atmosphere that extends far beyond that of Jupiter. However, the exact mechanism that led to such an expansion remains a mystery that challenges current theories on planetary formation. In particular, current models fail to explain how a planet can accumulate such an extensive and thin atmosphere. The mechanisms usually invoked to explain the evolution of planetary atmospheres, such as the escape of gas or collisions with other celestial objects, seem in fact insufficient to explain the magnitude of the expansion observed in WASP-193b. Francisco Pozuelos, an astronomer at the Institute of Astrophysics of Andalusia, concludes that: ” WASP-193b is a cosmic mystery. Solving it will require more observational and theoretical work, including measuring its atmospheric properties with the James Webb Space Telescope and comparing them with the various theoretical mechanisms that could lead to such extreme inflation.“In sum, the discovery of WASP-193b opens exciting new avenues for exoplanet research and raises fascinating questions about the diversity and complexity of worlds beyond our solar system.
