Astronomers find three potential super-Earths orbiting a 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 from the University of Exeter.

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

The researchers emphasize the importance of this discovery, noting that this orange star looks somewhat like our Sun and represents the closest planetary system to which a super-Earth could reside in the habitable zone around a Sun-like star.

The study describing 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 solar-type stars.”

These potential super-Earths, planets with masses greater than Earth but significantly less than the solar system’s ice giants Uranus and Neptune, were identified through 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 star’s subtle movements caused by orbiting planets, are crucial in such discoveries. By analyzing the spectrum of the star’s light, researchers can determine whether it is moving toward us (blueshift) or away from us (redshift). To ensure the accuracy of their findings, the team used different methodologies and comparative analyses.

The survey revealed three planetary candidates with minimum masses ranging from 5 to 11 times that of Earth. The team suggests that the close proximity to the star, combined with the favorable orbit of the outer planet, makes this system a promising target for future high-contrast direct imaging and high-resolution spectroscopic studies.

Dr. Dalal added: “This discovery highlights the importance of long-term monitoring and advanced techniques in uncovering the secrets of distant galaxies. We are eager to continue our observations and look for new planets in the system.”

This discovery opens new doors for understanding planetary systems and the potential for life beyond our solar system.