New discoveries of exoplanets accumulate rapidly in recent years, and when astronomers confirm the existence of another planet, there is always an immediate interest in whether this planet can sustain life. For many of the newly discovered worlds the answer is firmly "no". They are either too hot, too cold, or they are just big balls of gas, but when you discover a rocky world that is just off it remains the chance to live.
A new study was published in Letters of astronomy and astrophysics explains how even some planets in the so-called "Golden Zone" of their parent stars can be doomed to the raw fate without the opportunity to support life as we know it.
For a planet to sustain life as we know it on Earth, it must have some kind of atmosphere. It is believed that many young planets form atmospheres at the beginning of the day, which sounds like great news to anyone who hopes that humanity finds extraterrestrial life in space someday but has a small catch.
Young planets are often in orbit around the young star, and scientists are starting to realize now more than ever how difficult a planet is to hold on to its atmosphere as an active young star.
The document explains that an abundance of M-dwarf stars, which are considered the most numerous in our neck in the forest, can make life very difficult for the planets that surround them. Unlike stars like our Sun, M-dwarf stars pass through particularly active bands at an early age, emitting increased amounts of X-ray and ultraviolet radiation for billions of years.
It is this radiation that can quickly break down the nearby planet from its atmosphere. In fact, even a planet with a Earth-like atmosphere can completely lose it in a million years if it travels around a particularly active young star. This is not great news for alien hunters, but it tells us a lot about how unique the Earth is and it can help us reduce the demand for extraterrestrial life in the future.