A study, which had the participation of four Portuguese astronomers, points to evidence of a planet outside our solar system with “a large ocean of liquid water”, orbiting a star a little older than the Sun.
The study, published in the specialty journal Astronomy & Astrophysics, had the contribution of astronomers doing research at the Institute of Astrophysics and Space Sciences, which released the results of the work in a statement.
“There is a high probability of liquid water on the surface” of the planet LHS 1140 b, “which is in the habitability zone” of the star LHS 1140, a red dwarf 41 light years away from Earth, in the direction of the constellation of Whale, explains one of the team’s researchers, João Faria.
Liquid water is a fundamental element for life as it is known. Therefore, according to the same astronomer, cited in the statement, this exoplanet constitutes “one of the best targets for future research by biomarkers”.
To arrive at the conclusion that LHS 1140 b may have a surface covered with liquid water, astronomers calculated the planet’s density and characterized its internal composition from data collected by the TESS space telescope and the ESPRESSO spectrograph in Chile.
Using the same data sources, they were able to detect traces of two more planets around the red dwarf (in addition to the other two that had been previously discovered, including LHS 1140 b).
The star LHS 1140 is about five billion years old (the Sun will be 4600 million years old) and a surface temperature of around 3000 degrees Celsius, “just over half the temperature of the Sun”.
Since LHS 1140 is less hot than the Sun, the star’s “habitability zone” – an area that offers conditions for rocky planets in its orbit, such as LHS 1140 b, to have liquid water on the surface – “is closer”. Considered the terrestrial type, the extrasolar planet LHS 1140 b it orbits its star in 24.7 days and is 1.7 times the diameter of the Earth and 6.5 times its mass.
“This is another big step that we have taken in the search for another Earth”, underlines the astronomer Sérgio Sousa, also mentioned in the statement of the Institute of Astrophysics and Space Sciences.