Astronomers have confirmed an exoplanet that might support life just 20 light-years away. Named HD 20794 d, the planet orbits a Sun-like star at the right distance for liquid water.
Scientists say HD 20794 d is nearly six times Earth’s mass. It orbits its star at an ideal distance, making conditions for water possible. This crucial factor increases its potential habitability as an exoplanet.
Michael Cretignier, an astrophysicist at Oxford University, expressed excitement. “Confirming the exoplanet’s existence was a huge joy,” he said. “It’s close enough that future missions may even capture an image of it.”
THE SEARCH FOR LIQUID WATER
Water is essential for life. Planets too close to their stars lose water due to extreme heat. Those too far become frozen worlds. The zone where water remains liquid is called the habitable zone for an exoplanet.
HD 20794, a yellow dwarf star, offers a stable environment. It is slightly smaller and older than the Sun. Its longevity means any exoplanets orbiting it could have stabilized over time.
A LONG JOURNEY TO CONFIRMATION
The discovery of HD 20794 d took years. In 2011, astronomers found three exoplanets in the system. But details remained elusive. In 2022, Cretignier detected a faint wobble in the star’s light spectrum. This subtle movement suggested an unseen exoplanet’s gravitational pull.
To confirm the finding, researchers collected more data. They used the European Southern Observatory‘s ESPRESSO instrument, an advanced tool for detecting exoplanets. The additional observations validated the existence of the exoplanet.
CHARACTERISTICS OF HD 20794 D
HD 20794 d has a minimum mass of 5.82 Earth masses. Its radius is estimated between 1.7 and 2.1 times that of Earth. It completes an orbit around its star in 648 days.
Yet, there are uncertainties. The exoplanet follows an elliptical orbit. It spends part of its journey in the habitable zone. At its farthest point, it moves into a freezing region.
ROCKY WORLD OR MINI-NEPTUNE?
Astronomers are unsure about the exoplanet’s composition. Without knowing its exact radius, they can’t determine its density. If it has a smaller radius, it could be a rocky super-Earth. A larger radius suggests a gaseous mini-Neptune, which may not support life.
Further studies are needed to clarify these details about the exoplanet.
FUTURE EXPLORATION
Cretignier is eager to see what comes next. “Finding new worlds is my job, but I’m excited to learn more about this exoplanet,” he said. “Its proximity makes it a fascinating target for future research.”
This discovery fuels hope for finding life beyond Earth. As technology advances, scientists may soon reveal more about this intriguing exoplanet.
The research is published in Astronomy & Astrophysics.
