Top News

New Delhi: A team of astronomers have investigated the surface composition of the rocky exoplanet designated as LHS 3844 b, at a distance of about 48.5 lightyears from the Earth in the southern constellation of Indus. Most such studies investigate the composition of the planetary atmosphere, with the study representing the next step in capabilities for characterising exoplanets, with the scientists revealing the surface composition of the barren, airless world. LHS 3844 b is a rocky exoplanet about 30 per cent larger than Earth, in a tight orbit around a cool red dwarf star. A year on the distant world lasts only 11 Earth hours.

The exoplanet approaches within three stellar diameters above the surface of the host star, and is tidally locked, just like the Moon is tidally locked to the Earth. One rotation takes just as long as one revolution, or the length of a day matches the length of a year. As a result, the same hemisphere constantly faces the host star, with an average day side temperature of 725°C. Observations by the James Webb Space Telescope have revealed a dark, hot, barren rock without any atmosphere. The dark surface may make the exoplanet resemble a larger version of the Moon or Mercury, both of which have a dry, desiccated surface.

Geological Activity LHS 3844 b

Sophisticated modelling has ruled out a composition similar to the Earth’s crust with silicate-rich minerals and granite. The planet is likely to contain little water, and does not have plate tectonics like the Earth, that results in a solid crust rich in silicates. The material is similar to lunar basalt, or the mantle material in the interior of the Earth. The surface is also likely to be weathered, with the material ground into a fine, abrasive dust like lunar regolith. The planet could have a crust made up of basaltic or magmatic minerals, and have undergone significant weathering. A paper describing the research has been published in Nature Astronomy.