red dwarf Archives

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.

February 2, 2024February 2, 2024 by Evan Gough

A Super-Earth (and Possible Earth-Sized) Exoplanet Found in the Habitable Zone

Artist depiction of the surface of a super-Earth orbiting a red dwarf. Credit: ESO/M. Kornmesser

Astronomers have found a new Super-Earth orbiting an M-dwarf (red dwarf) star about 137 light-years away. The planet is named TOI-715b, and it’s about 1.55 Earth’s radius and is inside the star’s habitable zone. There’s also another planetary candidate in the system. It’s Earth-sized, and if it’s confirmed, it will be the smallest habitable zone planet TESS has discovered so far.

January 29, 2024January 29, 2024 by Evan Gough

Another Explanation for K2-18b? A Gas-Rich Mini-Neptune with No Habitable Surface

Artist depiction of the mini-Neptune K2-18 b. Credit: NASA, CSA, ESA, J. Olmstead (STScI), N. Madhusudhan (Cambridge University)

Exoplanet K2-18b is garnering a lot of attention. James Webb Space Telescope spectroscopy shows it has carbon and methane in its atmosphere. Those results, along with other observations, suggest the planet could be a long-hypothesized ‘Hycean World.’ But new research counters that.

Instead, the planet could be a gaseous mini-Neptune.

January 17, 2023January 17, 2023 by Evan Gough

Worlds Bustling With Plantlife Should Shine in a Detectable Wavelength of Infrared

Artist's rendering of a super-Earth-type exoplanet, TOI 1452 b. Credit: Benoit Gougeon, Université de Montréal.

Future historians might look back on this time and call it the ‘exoplanet age.’ We’ve found over 5,000 exoplanets, and we’ll keep finding more. Next, we’ll move beyond just finding them, and we’ll turn our efforts to finding biosignatures, the special chemical fingerprints that living processes imprint on exoplanet atmospheres.

But there’s more to biosignatures than atmospheric chemistry. On a planet with lots of plant life, light can be a biosignature, too.

December 17, 2021December 17, 2021 by Matt Williams

Would Mars be More Habitable if it Orbited a Red Dwarf?

Artist’s rendering of an exoplanet system experiencing atmospheric escape in connection with its host star. Credit: MACH Center / Aurore Simonnet

Thanks to the explosion in discoveries made in the last decade, the study of extrasolar planets have entered a new phase. With 4,884 confirmed discoveries in 3,659 systems (and another 7,958 candidates awaiting confirmation), scientists are shifting their focus from discovery to characterization. This means examining known exoplanets more closely to determine if they possess the necessary conditions for life, as well as “biomarkers” that could indicate the presence of life.

A key consideration is how the type of star may impact a planet’s chances of developing the right conditions for habitability. Consider red dwarf stars, the most common stellar class in the Universe and a great place to find “Earth-like,” rocky planets. According to a new study by an international team of scientists, a lifeless planet in our own backyard (Mars) might have evolved differently had it orbited a red dwarf instead of the Sun.

December 8, 2021December 8, 2021 by Evan Gough

TESS Finds a New Mars-Sized Planet (With the Density of Mercury)

An artist's illustration of a hypothetical exoplanet orbiting a red dwarf. Image Credit: NASA/ESA/G. Bacon (STScI)

Some planets orbit their stars so closely that they have extremely high surface temperatures and extremely rapid orbits. Most of the ones astronomers have found are Hot Jupiters— planets in the size range of Jupiter and with similar compositions as Jupiter. Their size and proximity to their star make them easier to spot using the transit method.

But there’s another type of planet that also orbits very close to their stars and has extremely high surface temperatures. They’re small, rocky, and they orbit their star in less than 24 hours. They’re called ultra-short-period (USP) planets and TESS found one that orbits its star in only eight hours.

And the planet’s density is almost equivalent to pure iron.

October 13, 2021October 13, 2021 by David Dickinson

LOFAR Sees Strange Radio Signals Hinting at Hidden Exoplanets

LOFAR sees ‘exoplanet aurorae’ near distant red dwarf suns.

A powerful new method may help to detect exoplanets, via the aurorae they induce on their host star. The finding was announced recently from ASTRON’s Low Frequency Array radio telescope (LOFAR), based out of Exloo in the Netherlands, and sprawled across sites in Europe.

January 8, 2020January 8, 2020 by Evan Gough

TESS Finds its First Earth-Sized World in the Habitable Zone of a Star

An artist's illustration of TOI 700d, an Earth-size exoplanet that TESS found in its star's habitable zone. Image Credit: NASA

NASA’s TESS (Transiting Exoplanet Survey Satellite) has found its first Earth-sized planet located in the habitable zone of its host star. The find was confirmed with the Spitzer Space Telescope. This planet is one of only a few Earth-sized worlds ever found in a habitable zone.

April 25, 2019April 25, 2019 by David Dickinson

Astronomers Catch a Superflare From a Puny Star

You can be thankful that we orbit a placid, main sequence, yellow dwarf star. Astronomers recently spied a massive superflare on a diminutive star, a powerful, radiation spewing event that you wouldn’t want to witness up close.

October 19, 2018 by Evan Gough

A Red Dwarf Blasts off a Superflare. Any Life on its Planets Would Have a Very Bad Day

The violent outbursts from red dwarf stars, particularly young ones, may make planets in their so-called habitable zone uninhabitable. Image Credit: Credit: NASA, ESA, and D. Player (STScI)

The most common type of star in the galaxy is the red dwarf star. None of these small, dim stars can be seen from Earth with the naked eye, but they can emit flares far more powerful than anything our Sun emits. Two astronomers using the Hubble space telescope saw a red dwarf star give off a powerful type of flare called a superflare. That’s bad news for any planets in these stars’ so-called habitable zones.

Red dwarfs make up about 75% of the stars in the Milky Way, so they probably host many exoplanets. In fact, scientists think most of the planets that are in habitable zones are orbiting red dwarfs. But the more astronomers observe these stars, the more they’re becoming aware of just how chaotic and energetic it can be in their neighbourhoods. That means we might have to re-think what habitable zone means.

“When I realized the sheer amount of light the superflare emitted, I sat looking at my computer screen for quite some time just thinking, ‘Whoa.'” – Parke Loyd, Arizona State University.

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