This rainy exoplanet could be ripe for life
https://www.sciencemag.org/news/2020/02/rainy-exoplanet-could-be-ripe-life
Source: By Daniel Clery. Science Magazine.
Excerpt: A nearby exoplanet with rainclouds in its atmosphere may have habitable conditions at its surface, researchers report today. The planet, dubbed K2-18b, is 124 light-years away and 2.6 times the radius of Earth. Last year, astronomers detected clouds of liquid water in the planet’s hydrogen-rich atmosphere, a first for such a small planet. [https://www.sciencemag.org/news/2019/09/hints-rain-clouds-found-small-alien-world] ...Now, a team of researchers in the United Kingdom describe in The Astrophysical Journal Letters how they calculated a range of possible atmospheres for the planet, based on its mass, size, and previously measured spectra of light that passed from K2-18b’s star through its atmosphere. (Molecules in the planet’s atmosphere absorb certain frequencies of light, so if the starlight passes through it on its way to Earth, the light’s spectrum can reveal those molecules.) They then used those possibilities to limit what conditions could exist in the planet’s interior. Their conclusion: The heart of K2-18b could be anything from a ball of almost pure iron with a hefty hydrogen atmosphere, to something more Neptune-like, to a water world with a lighter atmosphere and ocean conditions similar to Earth....
Source: By Daniel Clery. Science Magazine.
Excerpt: A nearby exoplanet with rainclouds in its atmosphere may have habitable conditions at its surface, researchers report today. The planet, dubbed K2-18b, is 124 light-years away and 2.6 times the radius of Earth. Last year, astronomers detected clouds of liquid water in the planet’s hydrogen-rich atmosphere, a first for such a small planet. [https://www.sciencemag.org/news/2019/09/hints-rain-clouds-found-small-alien-world] ...Now, a team of researchers in the United Kingdom describe in The Astrophysical Journal Letters how they calculated a range of possible atmospheres for the planet, based on its mass, size, and previously measured spectra of light that passed from K2-18b’s star through its atmosphere. (Molecules in the planet’s atmosphere absorb certain frequencies of light, so if the starlight passes through it on its way to Earth, the light’s spectrum can reveal those molecules.) They then used those possibilities to limit what conditions could exist in the planet’s interior. Their conclusion: The heart of K2-18b could be anything from a ball of almost pure iron with a hefty hydrogen atmosphere, to something more Neptune-like, to a water world with a lighter atmosphere and ocean conditions similar to Earth....