M dwarfs tagged posts

How did the molecular building blocks for life end up on Earth? One long-standing theory is that they could have been delivered by comets. Now, researchers from the University of Cambridge have shown how comets could deposit similar building blocks to other planets in the galaxy.

In order to deliver organic material, comets need to be travelling relatively slowly – at speeds below 15 kilometres per second. At higher speeds, the essential molecules would not survive – the speed and temperature of impact would cause them to break apart.

The most likely place where comets can travel at the right speed are ‘peas in a pod’ systems, where a group of planets orbit closely together...

Researchers show young stars rapidly destroy Earth-like Nitrogen dominated atmospheres. Fundamentally important for the habitability of a planet is whether or not it can hold onto an atmosphere, which requires that the atmosphere is not completely lost early in the lifetime of the planet. A new study by researchers based at the University of Vienna and at the Space Research Institute of the ÖAW in Graz has shown that young stars can rapidly destroy the atmospheres of potentially-habitable Earth-like planets, which is a significant additional difficulty for the formation of life outside our solar system. The results will appear soon in the journal Astronomy & Astrophysics Letters.

Much recent research has focused on planets orbiting stars called M-dwa...

Artists impressions of a habitable planet around M-dwarfs (left) and primordial Earth (right). The surface of M-dwarf planet is illuminated by visible light. On the other hand, similar light conditions are expected underwater, since only blue-green light can penetrate meters of water. Credit: Copyright Astrobiology Center

Researchers at the Astrobiology Center (ABC) of National Institutes of Natural Science (NINS) in Japan and their colleagues have proposed a prediction that red-edge could be observed as on the Earth even on exoplanets around M-dwarfs. They pointed out that the first oxgenic photorophs are most likely to have evolved underwater to utilize visible light just like what had happened in the primordial ocean on the Earth...

The figures show the wind, temperature, and surface-atmosphere friction on a planet 1.45 times the size of the Earth in a 1-day orbit around an M dwarf. The two topmost figures show the wind and the temperature in the upper layers of the atmosphere. The two figures in the middle show the wind and the temperature on the surface of the planet. On the left-hand figures, the surface-atmosphere friction equals that on Earth. On the right-hand figures, there is ten times as much friction between surface and atmosphere than is the case on Earth. Both scenarios have a different impact on the climate of a planet: the climate represented in the right-hand figures is more habitable. Credit: KU Leuven – Ludmila Carone and Leen Decin

Astronomers from KU Leuven, Belgium, have shown that the interaction ...