HARPS-N scores a new goal: three Potential Super-Earths Around the Star HD 48948

An international team of researchers led by Dr Shweta Dalal (University of Exeter), discovered three potential "super-Earth" exoplanets orbiting the relatively nearby orange dwarf star HD 48948, located at about 55 light-years from Earth.

These three potential Super-Earths planets with a mass greater than Earth but significantly less than the Solar System's ice giants Uranus and Neptune (from 5 to 11 times the mass of Earth), 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 (High Accuracy Radial velocity Planet Searcher in North hemisphere) installed at the Telescopio Nazionale Galileo. Radial velocity measurements, which track the star's subtle movements caused by orbiting planets, are crucial in such discoveries. By analysing the spectrum of light from the star, researchers can determine whether it is moving towards us (blueshift) or away from us (redshift). The proximity of the star, combined with the outermost planet's favourable orbit, makes this system a promising target for future high-contrast direct imaging and high-resolution spectroscopic studies.

The three exoplanets revolve around their host star in 7, 38, and 151 Earth days, respectively. Notably, the outermost exoplanet candidate resides in the habitable zone of its host star, where conditions could allow liquid water to exist without boiling or freezing. This region, often referred to as the Goldilocks zone, is considered ideal for potentially supporting life.

The team highlights the importance of this discovery, noting that this orange star is somewhat similar to our Sun and represents the closest planetary system to host a Super-Earth in the habitable zone around a Sun-like star.

Dr Dalal said: "The discovery of this Super-Earth in the habitable zone around an orange star is an exciting step forward in our quest to find habitable planets around solar-type stars and highlights the importance of long-term monitoring and advanced techniques in uncovering the secrets of distant star systems. We are eager to continue our observations and look for additional planets in the system."

Link to the paper: https://doi.org/10.1093/mnras/stae1367

Artistic Impression of planetary system HD48948 which is located at a distance of 55 light-years from Earth. The Voyager 1 spacecraft with its current speed would take almost one million years to reach HD48948. Image Credits: Soumita Samanta (https://www.soumitasamanta.com)