One of the lightest exoplanets ever discovered

With a mass of only half that of Earth, GJ 367b is a true lightweight.

Thanks to extensive searches, we know that thousands of so-called exoplanets can be found outside our solar system. A quarter of a century after the first discovery, the focus has now shifted from hunting exoplanets to precisely characterizing these worlds. For example, do they resemble Earth, or are they strange and exotic planets? In a new study, researchers looked at GJ 367b; Planet orbiting a red dwarf star. The results show that astronomers have found a real lightweight here.

crossing style
Many exoplanets known to us have been discovered using the transit method. This includes telescopes that stare at stars for extended periods of time, hoping that the brightness of those stars will periodically decrease slightly. This dip could be caused by a planet moving in front of the star and temporarily blocking part of the star’s light. GJ 367b was also discovered by TESS planetary hunter using the transit method. And now the exploration of this world continues. Because today, thanks to innovative technologies, it is possible to accurately describe most of the exoplanets.

GJ 367b
What we know so far about GJ 367b is that the planet is about 9,000 kilometers in diameter. In these dimensions, the exoplanet is slightly larger than our neighboring planet Mars. The planetary system is located just under 31 light-years from Earth, which makes it ideal for further research.

pulp
Astronomers have now been able to determine the mass of GJ 367b, among other things. Compared to other planets outside our solar system, GJ 367b is as light as a feather. For example, the mass of the planet is only half the mass of the Earth. This makes GJ 367b one of the approximately 5,000 exoplanets we know today.

Very fast
Not only is GJ 367b as light as a feather, the planet is also very fast. For example, a planet takes about eight hours to complete one revolution around its parent star. With this orbital period of only one-third of Earth’s day, the planet belongs to the so-called planets very short periodPlanets that take less than 24 hours to orbit their parent star. “We already know a little, but their origin is currently unknown,” said researcher Christine Lamm. “By measuring the exact basic properties of the USP planets, we can get a glimpse into their formation and evolution history.”

blazing hot
GJ 367b orbits the star GJ 367; A red dwarf star is only half the size of our Sun. Due to the proximity of an exoplanet to its parent star, GJ 367b is exposed to a very high level of radiation, more than 500 times stronger than the amount of radiation bombarding the Earth. So the temperatures are very high: up to 1500 ° C. At such scorching temperatures, all rocks and minerals melt. This means that GJ 367b – unfortunately – cannot be considered second Earth.

rocky
Now that researchers have a better understanding of GJ 367b’s radius and mass, they can also draw conclusions about its internal structure. According to the researchers, the planet is somewhat similar to Mercury. GJ 367b turns out to be rocky and has a high density. “The higher density indicates that the planet has an iron core,” said researcher Szilárd Csizmadia. “These properties are similar to those of Mercury, which differs from the other terrestrial planets in our solar system by a disproportionately large iron-nickel core.”

The study shows that it is possible to accurately determine the characteristics of smaller and less massive exoplanets. These studies are very interesting. It’s actually a key to understanding how terrestrial planets form and evolve, the researchers say. So the search continues. In addition, red dwarf stars are known to orbit on average two to three planets. And so it’s possible that GJ 367b has some equally wonderful brothers.