Posted on by Evan Gough

Ocean Salinity Affects Earth’s Climate. How About on Exoplanets?

Image of Earth from 2020, over the South Pacific Ocean from the EPIC camera on the DSCOVR satellite. Many things affect Earth's albedo, including clouds, snow cover, and vegetation. How does exoplanet vegetation affect albedo and climate? Credit: NASA/NOAA

There’s a link between Earth’s ocean salinity and its climate. Salinity can have a dramatic effect on the climate of any Earth-like planet orbiting a Sun-like star. But what about exoplanets around M-dwarfs?

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Posted on by Matt Williams

Habitable Planet’s Orbiting Red Dwarf Suns Could at Risk from Far-Ultraviolet Radiation

Artist's depiction of red-dwarf-flare. Image credit: Casey Reed/NASA

The question of whether or not red dwarf stars can support habitable planets has been subject to debate for decades. With the explosion in exoplanet discoveries in the past two decades, the debate has become all the more significant. For starters, M-type (red dwarf) stars are the most common in the Universe, accounting for 75% of the stars in our galaxy. Additionally, exoplanet surveys indicate that red dwarfs are particularly good at forming Earth-like rocky planets that orbit within their circumsolar habitable zones (CHZs).

Unfortunately, a considerable body of research has shown that planets orbiting red dwarf suns would be subject to lots of flare activity – including some so powerful they’re known as “superflares.” In a recent study led by the University of Hawai’i, a team of astrophysicists revealed that red dwarf stars can produce stellar flares with significantly more far-ultraviolet radiation than previously expected. Their findings could have drastic implications for exoplanet studies and the search for extraterrestrial life on nearby rocky planets.

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Posted on by Evan Gough

TRAPPIST-1 Outer Planets Likely Have Water

Three of the TRAPPIST-1 planets – TRAPPIST-1e, f and g – dwell in their star’s so-called “habitable zone. CreditL NASA/JPL

The TRAPPIST-1 solar system generated a swell of interest when it was observed several years ago. In 2016, astronomers using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) at La Silla Observatory in Chile detected two rocky planets orbiting the red dwarf star, which took the name TRAPPIST-1. Then, in 2017, a deeper analysis found another five rocky planets.

It was a remarkable discovery, especially because up to four of them could be the right distance from the star to have liquid water.

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