Astronomers discover three potential super-Earths around nearby star

Astronomers have discovered three potential ‘super-Earth’ exoplanets orbiting a relatively nearby orange dwarf star. This groundbreaking discovery was made by an international team of researchers led by Dr Shweta Dalal of the University of Exeter.

The exoplanets orbit the star HD 48498, which is about 55 light-years from Earth. These planets orbit their parent star in 7, 38, and 151 Earth days, respectively. Notably, the outermost exoplanet candidate lies in the habitable zone of its parent star, where conditions could support liquid water without boiling or freezing. This region, often referred to as the Goldilocks zone, is considered ideal for potentially supporting life.

The researchers emphasize the importance of this discovery, pointing out that this orange star bears some resemblance to our Sun and represents the closest planetary system with a super-Earth in the habitable zone around a Sun-like star.

The study with these findings was published in the journal MNRAS on June 24, 2024.

Dr Dalal said: “The discovery of this super-Earth in the habitable zone around an orange star is an exciting step forward in our search for habitable planets around Sun-like stars.”

These potential super-Earths, planets with a mass greater than Earth but significantly smaller than the solar system’s ice giants Uranus and Neptune, were identified by the HARPS-N Rocky Planet Search program. Over a decade, the team collected nearly 190 high-precision radial velocity measurements using the HARPS-N spectrograph.

Radial velocity measurements, which track the subtle movements of the star caused by orbiting planets, are crucial for such discoveries. By analyzing the star’s light spectrum, researchers can determine whether it is moving toward us (blueshift) or away from us (redshift). To ensure the accuracy of their results, the team used a variety of methods and comparative analyses.

The research revealed three planet candidates with minimum masses between 5 and 11 times that of Earth. The team suspects that the proximity of the star, combined with the favorable orbit of the outermost planet, makes this system a promising target for future high-contrast direct imaging and high-resolution spectroscopic studies.

Dr Dalal added: “This discovery underscores the importance of long-term monitoring and sophisticated techniques in unravelling the mysteries of distant star systems. We can’t wait to continue our observations and search for more planets in this system.”

This discovery opens new doors to understanding planetary systems and the possibility of life outside our solar system.