The system around HD 158259 star consists of an innermost large rocky planet (a “super-Earth”) and five small gas giants (“mini-Neptunes”) that have exceptionally regular spacing between them.
Astronomers have found an exoplanet more than twice the size of Earth to be potentially habitable, opening the search for life to planets significantly larger than Earth but smaller than Neptune.
The habitable-zone planet is one of three orbiting a star known as TOI 700, a cool M dwarf located about 100 light-years from Earth. The candidate planet, TOI 700 d, is is at a distance where temperatures would allow water to exist in liquid form.
We get excited when we detect water on another world, which so far hasn’t happened often. But this study shows that the presence of water, though tantalizing and worth pursuing scientifically, guarantees nothing.
Astronomers using the Hubble space telescope have discovered water in the atmosphere of an exoplanet in its star’s habitable zone. The water was detected as vapour in the atmosphere. The planet is called K2-18b.
Accounting for the buildup of toxic gases predicted to occur in the atmospheres of most planets narrows the habitable zone for complex life by half and, in some cases, rules it out altogether, the study concludes.
Hopes for finding life on four rocky exoplanets relatively close to Earth have been boosted by new modelling that shows biological systems could survive the intense and prolonged bursts of X-ray and UV radiation.
A research into how life evolved on Earth has shown that water alone does not guarantee life – nor does the presence of oxygen gas. And that two other major biosignatures, carbon dioxide and carbon monoxide could be needed.
Barnard b or GJ 699 b – might have microbes or other simple life in its environment as long as there is a lot of thermal activity within the planet itself. This would theoretically provide enough energy for life to survive.
A new NASA-led study shows that Proxima b could support the existence of an ocean on its dayside, which means it could still be habitable.
Of the thousands of known exoplanets, Kepler-452b has the most ideal combination of UV light exposure and conditions for liquid water.