Astronomers discover “strange” Neptune-like exoplanets that may have clouds of water


Astronomers have discovered a planet just 90 light-years from Earth with a surprising atmosphere – and the possibility that clouds contain water.

TOI-1231 b is a Exoplanetwhich means it is outside of our solar system. It was discovered by a team of scientists from NASA’s Jet Propulsion Laboratory and the University of New Mexico, who will publish their results in an upcoming issue of the Astronomical Journal.

TOI-1231 b was detected with data from the Transiting Exoplanet Survey Satellite (TESS) and confirmed with the Planet Finder Spectrograph (PFS) at the Magellan Clay Telescope in Chile. The PFS revealed details about the exoplanet’s mass and orbits by observing its gravitational impact on its host star.

In just 24 earth days, TOI-1231 b completes an orbit of its nearby M dwarf star NLTT 24399, also known as the red dwarf, the most common type of star in the Milky Way.

NLTT 24399 is smaller, brighter and darker than our sun, which is what the detection of the new exoplanet pretty easy.

“If you imagine an Earth-like planet passing in front of a star the size of the Sun, it will block a tiny bit of light; but if it passes in front of a much smaller star, the proportion of light being blocked will be greater, “said scientists.” In a way, this creates a larger shadow on the star’s surface, making planets around M-dwarfs more recognizable and easier to locate are investigating. ”

Artist’s impression of TOI-1231b, a Neptune-like planet about 90 light years from Earth.

NASA / JPL-Caltech

The perfect candidate for observation

Astronomers found that TOI-1231b “strangely resembles Neptune” in both size and density, leading them to believe that it is also gaseous – not rocky like Earth. However, its temperature is more similar to that of our home planet.

“Although TOI 1231b is eight times closer to its star than Earth is to the Sun, its temperature is similar to Earth thanks to its cooler and less bright host star,” said study co-author Diana Dragomir. “However, the planet itself is actually larger than Earth and a bit smaller than Neptune – we could call it a sub-Neptune.”

With a temperature of around 140 degrees Fahrenheit, the TOI-1231b is one of the coolest little ones Exoplanets available for future atmospheric studies ever discovered.

“Compared to most of the transit planets discovered so far, that often scorching temperatures in the many hundreds or thousands of degrees, TOI-1231b is positively cold, “said lead author Jennifer Burt.

Previous research suggests that planets with such a low temperature might have clouds in their atmosphere. Recently discovered K2-18 showed evidence of water clouds – shocking scientists.

“TOI-1231b is one of the few other planets we know to be of similar size and temperature, so future observations of this new planet will allow us to determine how often (or rarely) water clouds form around them . ” temperate worlds, “said Burt.

And that’s not the only peculiarity of the planetary system. It is moving away from Earth at such a rapid rate that researchers can easily see hydrogen atoms escaping from its atmosphere – like a tail trailing behind the planet.

“The low density of TOI-1231 b suggests that it is surrounded by a sizeable atmosphere and is not a rocky planet. But the composition and extent of this atmosphere are unknown!” said Dragomir. “TOI-1231b could have a large hydrogen or hydrogen-helium atmosphere, or a denser water vapor atmosphere. Each of them would point to a different origin and enable astronomers to understand whether and how planets around M-dwarfs form differently than the planets around our sun, for example. “

A new era for exoplanet studies

NASA researchers say these types of discoveries will usher in a new era in exoplanet research. You move from simply discovering these unusual planets to actually observing certain worlds and understanding their atmospheres.

Using a technique called transmission spectroscopy, scientists hope to capture starlight in the planet’s atmosphere. Molecules in the atmosphere absorb this light, leaving dark lines “that can be read like a barcode” and revealing its gaseous composition.

One of the most fascinating results of the last two decades of exoplanet research is that none of the new planetary systems we have discovered looks like our own solar system, ”said Burt. “They are full of planets between the sizes of Earth and Neptune in orbits much shorter than Mercury’s, so we have no local examples to compare them to.”

Researchers plan to further study the planet using the Hubble Space Telescope later this month. They also hope to continue their observations and do their research with the help of the James Webb Space Telescope, should come on the market this year.

“This new planet we discovered is still weird – but it’s one step closer to being like our neighboring planets,” said Burt.

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