Researchers identify potentially life-sustainable exoplanets

International teams have confirmed the discovery of super-Earth orbits in habitable zones of nearby sun-like stars. The planet was originally detected two years ago by Oxford University scientist Dr. Michael Cletinier. The results open a window into future research on exoplanets like Earth that may have life-friendly conditions, based on observations over 20 years.

The new planet named HD 20794 D has six times the mass of a star resembling our Sun, just 20 light years away. That trajectory is located within the system’s habitable zone. That is, it is at the right distance from the star and maintains liquid water on its surface. This is, as we know, an important ingredient in life. This paper is published in Journal Astronomy & Astrophysics.

Dr. Cretignier first identified candidates’ exoplanet signals in 2022 and analyzed archival data recorded by HARPS (High-precision radial fast planet searcher) spectroscopy at the La Silla Observatory in Chile. This data analyzes the light absorbed and emitted by the object.

Dr. Cletinier discovered a clear and periodic shift in the spectrum of light emitted by the host star, which could have been caused by the gravity pull of a nearby planet. However, due to the faintness of the signal, it was not clear whether this was caused by a planet, the stars themselves, or by tool errors.

To verify the signal, an international team analyzed extremely excellent measurements recorded over 20 years by Chilean Harps and its successor Espresso. These instruments are one of the most advanced in the world for measuring small variations in the optical spectrum.

“We worked on data analysis for years and gradually analyzed and eliminated all the causes of contamination,” added Dr. Cletinier. Advanced processing methods and thorough analysis were required to distinguish planetary signals from background noise and subtle instrumental effects. The findings were finally confirmed by combining the results of the two instruments.

“For me, it was a natural pleasure to be able to see the planet existed,” Dr. Cletinier said. “It was a relief because the original signal was at the edge of the spectrograph’s detection limit. So it was difficult to fully convince at that point whether the signal was genuine or not.) It means there is hope for a space mission to get an image of it.”

The planet is in the habitable zone of the system, but it is too early to say whether it can host life or not. Unlike most planets, the HD 20794 D’s orbit is elliptical rather than circular. The distance from the stars changes dramatically, and the planet moves from the outer edge of the habitable zone to the inner edge throughout the year.

In any case, the HD 20794 D provides valuable test cases for upcoming space projects designed to detect signs of life outside our solar system. These include very large telescopes, habitable world observatory, and large interferometers for exoplanets (life). These instruments observe the atmosphere of nearby Earth-like planets in habitable zones of life-indicating, habitable “biosignatures.”

Dr. Cretignier said, “Because its location and relatively close to Earth in a habitable zone, the planet could play a pivotal role in future missions, and its biological signatures representing potential life. It can characterize the atmosphere of an exoplanet to search for.”

“My job consists primarily of finding these unknown worlds, especially since it is one of the closest Earth analogs we know and are given its distinctive orbit. , I’m extremely keen to hear other scientists tell us about this newly discovered planet.”