Astronomers have finished analyzing known exoplanets and have found that the conditions of the earth on these potentially habitable worlds can be much rarer than previously believed. The researchers on the project focused on requirements for photosynthesis based on oxygen to develop on the planet. Photosynthesis would allow a complex biosphere of the type found on Earth.
Scientists continue to discover more exoplanets, with the number of confirmed planets of the Galaxy Milky Way, confirmed in thousands of people. Astronomers say the planets that are both similar to the earth and in the living area around their host star are much less common. Currently, we are only aware of a handful of rocky and potentially habitable exoplanets in our galaxy. However, the new research indicates that none of these planets has only theoretical conditions to maintain a biosphere similar to the land resulting from oxygen photosynthesis.
Oxygenic photosynthesis is the mechanism that plants use to convert light and carbon dioxide into oxygen and nutrients here on Earth. The only exoplanet that approaches stellar radiation required to support a large biosphere is Kepler-442B. This planet is rocky, but about twice the mass of the earth and orbits a moderately hot host star. It is about 1200 light-years of the earth.
Researchers on the study studied in detail the amount of energy received by a planet of its host star and whether living organisms efficiently produce nutrients and molecular oxygen, both of which are essential for complex life. that we know him. The team discovered that the stars around half of the sun temperature can not undergo a biosphere resembling the ground because they do not have enough energy in the correct wavelength range.
However, oxygenic photosynthesis would always be possible on the orbit planets of these stars, but the planets could not maintain a rich biosphere. The orbit planets of a red dwarf star would not receive enough energy to support active photosynthesis. The hottest stars that the sun would emit up to 10 times more radiation than the beach necessary for an effective photosynthesis, but do not live long enough for the complex life to evolve. Since the red dwarf stars are by far the most common type of galaxy, the study indicates that the conditions of the Earth on other planets can be much less common than previously believed.
