red dwarf habitability Archives

August 5, 2024August 5, 2024 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.

March 22, 2024March 22, 2024 by Evan Gough

Finding Atmospheres on Red Dwarf Planets Will Take Hundreds of Hours of Webb Time

This illustration shows what exoplanet K2-18 b could look like based on science data. NASA’s James Webb Space Telescope examined the exoplanet and revealed the presence of carbon-bearing molecules. The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. But more extensive observations with the JWST are needed to understand its atmosphere with greater confidence. Image Credit: By Illustration: NASA, ESA, CSA, Joseph Olmsted (STScI)Science: Nikku Madhusudhan (IoA)

The JWST is enormously powerful. One of the reasons it was launched is to examine exoplanet atmospheres to determine their chemistry, something only a powerful telescope can do. But even the JWST needs time to wield that power effectively, especially when it comes to one of exoplanet science’s most important targets: rocky worlds orbiting red dwarfs.

March 15, 2024March 15, 2024 by Evan Gough

Could Earth Life Survive on a Red Dwarf Planet?

This artist's illustration shows planets orbiting a red dwarf star. Many red dwarfs have planets in their habitable zones, but red dwarf flaring might mean those zones aren't habitable at all. New research explores the idea. Image Credit: NASA

Even though exoplanet science has advanced significantly in the last decade or two, we’re still in an unfortunate situation. Scientists can only make educated guesses about which exoplanets may be habitable. Even the closest exoplanet is four light-years away, and though four is a small integer, the distance is enormous.

That doesn’t stop scientists from trying to piece things together, though.

February 3, 2024February 3, 2024 by Brian Koberlein

Atmospheres in the TRAPPIST-1 System Should be Long Gone

Illustration of the Trappist-1 system. Credit: NASA/JPL-Caltech

Trappist-1 is a fascinating exoplanetary system. Seven worlds orbiting a red dwarf star just 40 light-years away. All of the worlds are similar to Earth in mass and size, and 3 or 4 of them are potentially habitable. Imagine exploring a system of life-rich worlds within easy traveling distance of each other. It’s a wonderful dream, but as a new study shows it isn’t likely that life exists in the system. It’s more likely the planets are barren and stripped of their atmospheres.

January 5, 2024January 6, 2024 by Evan Gough

GJ 367b is Another Dead World Orbiting a Red Dwarf

This artist's concept illustrates a red dwarf star surrounded by exoplanets. Credit: NASA/JPL-Caltech

Red dwarf exoplanet habitability is a hot topic in space science. These small dim stars host lots of exoplanets, including small rocky ones the size of Earth. But the little stars emit extremely powerful flares that can damage and strip away atmospheres.

If we’re ever going to understand red dwarf habitability, we need to understand the atmospheres of the exoplanets that orbit them.

March 14, 2023March 14, 2023 by Evan Gough

Even the Calmest Red Dwarfs are Wilder than the Sun

An artist's conception of a violent flare erupting from the red dwarf star Proxima Centauri. Such flares can obliterate atmospheres of nearby planets. Credit: NRAO/S. Dagnello.

There’s something menacing about red dwarfs. Human eyes are accustomed to our benevolent yellow Sun and the warm light it shines on our glorious, life-covered planet. But red dwarfs can seem moody, ill-tempered, and even foreboding.

For long periods of time, they can be calm, but then they can flare violently, flashing a warning to any life that might be gaining a foothold on a nearby planet.

February 28, 2023March 1, 2023 by Matt Williams

Do Red Dwarfs Provide Enough Sunlight for Plants to Grow?

This artist’s impression shows the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image between the planet and Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. Credit: ESO/M. Kornmesser

To date, 5,250 extrasolar planets have been confirmed in 3,921 systems, with another 9,208 candidates awaiting confirmation. Of these, 195 planets have been identified as “terrestrial” (or “Earth-like“), meaning that they are similar in size, mass, and composition to Earth. Interestingly, many of these planets have been found orbiting within the circumsolar habitable zones (aka. “Goldilocks zone”) of M-type red dwarf stars. Examples include the closest exoplanet to the Solar System (Proxima b) and the seven-planet system of TRAPPIST-1.

These discoveries have further fueled the debate of whether or not these planets could be “potentially-habitable,” with arguments emphasizing everything from tidal locking, flare activity, the presence of water, too much water (i.e., “water worlds“), and more. In a new study from the University of Padua, a team of astrobiologists simulated how photosynthetic organisms (cyanobacteria) would fare on a planet orbiting a red dwarf. Their results experimentally demonstrated that oxygen photosynthesis could occur under red suns, which is good news for those looking for life beyond Earth!

February 6, 2023February 6, 2023 by Evan Gough

Earth-Sized Planet Found At One of the Lightest Red Dwarfs

Artist’s conception of a rocky Earth-mass exoplanet like Wolf 1069 b orbiting a red dwarf star. If the planet has retained its atmosphere, chances are high that it would feature liquid water and habitable conditions over a wide area of its dayside. Image Credit: NASA/Ames Research Center/Daniel Rutter

Astronomers have found another Earth-sized planet. It’s about 31 light-years away and orbits in the habitable zone of a red dwarf star. It’s probably tidally locked, which can be a problem around red dwarf stars. But the team that found it is optimistic about its potential habitability.

December 16, 2022December 16, 2022 by Evan Gough

Are Planets Tidally Locked to Red Dwarfs Habitable? It’s Complicated

habitable exoplanet interstellar message — Artist's impression of the exoplanet Ross 128 b orbiting its red dwarf star. Potetentially habitable rocky worlds like this one are beyond our physical reach. Image Credit: ESO/M. Kornmesser. Public Domain

Astronomers are keenly interested in red dwarfs and the planets that orbit them. Up to 85% of the stars in the Milky Way could be red dwarfs, and 40% of them might host Earth-like exoplanets in their habitable zones, according to some research.

But there are some problems with their potential habitability. One of those problems is tidal locking.

December 14, 2022December 14, 2022 by Evan Gough

Could Life Survive on Frigid Exo-Earths? Maybe Under Ice Sheets

This artist's illustration shows what an icy exo-Earth might look like. A new study says liquid water could persist under ice sheets on planets outside of their habitable zones. Image Credit: NASA

Our understanding of habitability relies entirely on the availability of liquid water. All life on Earth needs it, and there’s every indication that life elsewhere needs it, too.

Can planets with frozen surfaces somehow have enough water to sustain life?