Skip to main content
  1. Home
  2. Space
  3. News

Exoplanet with eccentric orbit discovered in the habitable zone of a red dwarf

Georgina Torbet
By

Astronomers have found a planet in the habitable zone of a red dwarf star, but its orbit is so elongated that it would have wildly variable temperatures and likely couldn’t support life.

The planet, named TOI-2257 b, was first spotted using data from NASA’s planet-hunting telescope TESS (Transiting Exoplanet Survey Satellite) and then observed in more detail using the Las Cumbres Observatory Global Telescope and the SAINT-EX telescope in Mexico. Using the SAINT-EX observations, the researchers were able to confirm that a planet was orbiting the red dwarf star every 35 days.

The SAINT-EX telescope.
The SAINT-EX telescope Institute of Astronomy, UNAM / E. Cadena

As red dwarf stars are smaller and cooler than our sun, the habitable zone around them, or the area in which liquid water could exist on the surface of an orbiting planet, is also different. Planets orbiting red dwarf stars could have liquid water even if they orbit much closer than the Earth orbits the sun. And having the planet close to the star also makes it easier to detect.

Recommended Videos

However, even though TOI-2257 b is in the habitable zone, don’t make any plans to move there just yet. The first issue with habitability is that the planet has a radius 2.2 times that of Earth, meaning it is large and likely gaseous with high atmospheric pressure. The second and most intriguing fact about this planet is that it has a highly eccentric orbit, meaning that its orbit traces an elliptical or oval shape rather than a circle. Sometimes the planet is close to its star, and other times it is further away.

Related

In fact, it has the most eccentric orbit of a planet around a cool star discovered to date. And that has a big effect on surface temperatures there.

“We found that TOI-2257 b does not have a circular, concentric orbit,” lead researcher Nicole Schanche explained in a statement. “In terms of potential habitability, this is bad news. While the planet’s average temperature is comfortable, it varies from -80°C to about 100°C depending on where in its orbit the planet is, far from or close to the star.”

The researchers are curious as to why the planet’s orbit is so eccentric, which could be due to a giant planet in the same system affecting this planet’s orbit. To learn more, the researchers hope that the planet could be studied further using the James Webb Space Telescope.

Editors' Recommendations

Topics
Georgina Torbet
Georgina Torbet
Space Writer
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
Astronomers spot an exoplanet creating spiral arms around its star
The Large Binocular Telescope in Arizona. The LBTI instrument combines infrared light from both 8.4-meter mirrors to image planets and disks around young and nearby stars.

When you imagine a galaxy like our Milky Way, you're probably picturing a swirl shape with arms reaching out from a central point. These spiral arms are a classic feature of many galaxies. Similar structures can be found around young stars which are surrounded by disks of matter from which planets form, called protoplanetary disks. Now, astronomers have discovered evidence that these structures could be created by recently formed exoplanets.

Astronomers used Large Binocular Telescope in Arizona to investigate a giant exoplanet named MWC 758c which seems to be forming the spiral arms around its host star. Located 500 light-years away, the star is just a few million years old, making it a baby in cosmic terms. "Our study puts forward a solid piece of evidence that these spiral arms are caused by giant planets," said lead researcher Kevin Wagner of the University of Arizona in a statement. "And with the new James Webb Space Telescope, we will be able to further test and support this idea by searching for more planets like MWC 758c."

Read more
This exoplanet is over 2,000-degrees Celsiu, has vaporized metal in its atmosphere
This artist impression illustrates how astronomers using the Gemini North telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, have made multiple detections of rock-forming elements in the atmosphere of a Jupiter-sized exoplanet, WASP-76b. The so-called “hot Jupiter” is perilously close to its host star, which is heating the planet’s atmosphere to astounding temperatures and vaporized rock-forming elements such as magnesium, calcium and iron, providing insight into how our own Solar System formed.

Astronomers have studied a strange, puffy, scorching-hot planet located 600 light-years away, and have seen elements that would normally form rocks, but are so hot that they have vaporized into the atmosphere.

The planet, named WASP-76b, is around the mass of Jupiter, but orbits its star 12 times closer than Mercury is to the sun. Being so close, its atmosphere its heated to a scorching 2,000- degrees Celsius, which makes it puff up to a large size that's six times the volume of Jupiter. These high temperatures also give astronomers the opportunity to observe elements that would normally be hard to identify in the atmosphere of a gas giant.

Read more
Tatooine-like exoplanet orbits two stars in rare astronomical discovery
An artist's illustration shows that the stars in the TOI 1338 system make an eclipsing binary — they circle each other in our plane of view.

Anyone who has watched Star Wars has likely found themselves enchanted by the views from Luke's home planet of Tatooine, with its pair of suns visible in the sky over the desert. As visually striking as this concept it, it isn't purely fantasy: there do exist planets that orbit two stars, called circumbinary systems, and standing on one of these planets you would see two stars in the sky.

Astronomers recently discovered one such planet, named BEBOP-1c. Located in the same system as a previously discovered planet, TOI-1338b, the team was trying to measure the mass of the older known planet when they discovered the new one. “Only 12 circumbinary systems are known so far, and this is only the second that hosts more than one planet,” said one of the researchers, David Martin of Ohio State University, in a statement.

Read more