Central Idea

Six exoplanets have been discovered orbiting HD 110067, a bright star in the Coma Berenices constellation, approximately 100 light-years away.
The planets’ radii range between that of Earth and Neptune, classifying them as ‘sub-Neptunes’.

About Sub-Neptune Exoplanets

Prevalence: Sub-Neptunes are commonly found in close-in orbits around more than half of all Sun-like stars.
Mystery: Despite their prevalence, the composition, formation, and evolution of these planets remain largely unknown.

TESS Observations: NASA’s Transiting Exoplanet Survey Satellite (TESS) observed dips in HD 110067’s brightness in 2020 and 2022.
CHEOPS Contribution: Additional observations from the CHaracterising ExOPlanets Satellite (CHEOPS) helped confirm the presence of six planets transiting the star.
Orbital Calculations: The study calculated the orbits of all six planets, ranging from about nine days for the innermost planet to approximately 54 days for the outermost planet.

Mass and Density Estimates: The planets have relatively low densities, suggesting the presence of large, hydrogen-rich atmospheres.
Resonant Orbits: All six planets are in resonant orbits, indicating regular gravitational interactions among them.
System’s Age: The resonant orbits suggest that the system has remained largely unchanged since its formation, estimated to be at least four billion years ago.

Brightness and Host Status: HD 110067 is the brightest star known to host more than four transiting exoplanets.
Potential for More Discoveries: There is a possibility of additional planets within or beyond the star’s temperate zone, though such observations have not yet been made.
Learning Opportunity: The HD 110067 system presents a unique opportunity to study sub-Neptunes and understand how such planetary systems form and evolve.