WORLD
New planet that may support alien life discovered 'close to Earth'

Baku, January 29, AZERTAC
Scientists appear to be one step closer in their mission to finding life outside Earth - after finding a new planet that may support alien life, according to Mirror.
The "promising" super-Earth - named HD 20794 d - is less than 20 light-years away from us and may even house water, according to the international research team that found it. Over the last 30 years, more than 7,000 exoplanets - ones that orbit a star outside the solar system - have been identified, with billions yet to be discovered.
But scientists are starting to take an interest in some of their characteristics as they continue on their mission of finding life elsewhere in the Universe. According to researchers, HD 20794 d, which is larger than Earth, sits in an "eccentric" orbit, allowing it to oscillate in and out of its star’s "habitable zone".
The discovery, published in the journal Astronomy & Astrophysics, comes after 20 years of observations using the world's best telescopes. HD 20794 d's ‘‘closeness’’ has made it easier to study as its light signals are more visible and stronger, researchers say. The current scientific consensus points to the existence of a planetary system for every star in our galaxy. Astronomers are now looking for exoplanets that are easier to characterise or have interesting features to test their theories and consolidate their knowledge.
According to the team who discovered the new planet, including scientists from the University of Geneva (UNIGE) in Switzerland, HD 20794 d is part of a planetary system containing two other planets. It orbits a G-type star, like the Sun, at a distance of just 19.7 light-years, which is, on the scale of the Universe, in the very close neighbourhood of Earth.
Prof Dumusque, of the Department of Astronomy at UNIGE, said: ‘‘HD 20794, around which HD 20794 d orbits, is not an ordinary star. Its luminosity and proximity makes it an ideal candidate for future telescopes whose mission will be to observe the atmospheres of exoplanets directly.’’ He says the interest in planet HD 20794 d lies in its position in the habitable zone of its star, the zone that delimits the place where liquid water can exist, one of the conditions necessary for the development of life as we know it.
Prof Dumusque said: "This zone depends on several factors, mainly the stellar properties. For stars such as the Sun or HD 20794, it can extend from 0.7 to 1.5 astronomical units (AU), encompassing not only the orbit of the Earth but also that of Mars in the case of the Sun. The exoplanet HD 20794 d takes 647 days to orbit its star, around 40 days less than Mars.
"Instead of following a relatively circular orbit, like the Earth or Mars, HD 20794 d follows an elliptical trajectory with large changes in the distance to its star during its revolution." He says the planet oscillates between the inner edge of its star HZ (0.75 AU) and outside of it (2 AU) along its orbit.
Prof Dumusque added: "This configuration is of particular interest to astronomers because it allows them to adjust theoretical models and test their understanding of the notion of a planet’s habitability. If there is water on HD 20794 d, it would pass from the state of ice to the liquid state, conducive to the appearance of life, during the planet’s revolution around the star."