Have you ever wondered what it would be like to live on a planet that is so close to its star that a year lasts only 7.7 hours? Well, you might not want to find out, because such a planet exists, and it is not a very hospitable place.
What is GJ 367b?
GJ 367b, also known as Tahay, is a sub-Earth-sized exoplanet that orbits a red dwarf star called Añañuca, about 31 light-years away from us in the constellation of Vela. It was discovered in 2021 by a team of astronomers using the Transiting Exoplanet Survey Satellite (TESS), a NASA mission that searches for planets around nearby stars
GJ 367b is one of the smallest and densest exoplanets ever found. It has a radius of about 72% of Earth’s, but a mass of about 63% of Earth’s. This means that its density is almost twice that of Earth’s, about 10.2 grams per cubic centimeter. To put that in perspective, that is denser than most metals, such as iron, which has a density of about 7.9 grams per cubic centimeter.
Why is GJ 367b so dense?
Scientists think that GJ 367b is mostly made of iron and that its outer layers of silicate rocks have been stripped away by either collisions or evaporation. This could have happened because GJ 367b is very close to its star, only about 1% of the distance between Earth and the Sun. This means that it receives about 500 times more radiation than Earth does from the Sun and that its surface temperature is about 1,500 degrees Celsius. That is hot enough to melt most metals, and even vaporize some of them.
Because of its proximity to its star, GJ 367b is also likely tidally locked, meaning that it always shows the same face to its star, just like the Moon does to Earth. This creates a huge contrast between the day and night sides of the planet, which could cause strong winds and weather patterns. However, GJ 367b probably does not have much of an atmosphere, because the intense radiation from its star would have blown it away.
What is the significance of GJ 367b?
GJ 367b is an example of a type of exoplanet that is very common in the galaxy, but very rare in our solar system. These are planets that are smaller than Earth, but larger than Mars, and that orbit very close to their stars. These planets are often called “sub-Earths” or “super-Mercuries”, depending on their size and composition.
These planets are interesting because they could tell us more about how planets form and evolve, and how different they can be from the ones we know. They could also help us understand the limits of habitability, and whether there are any chances of finding life on such extreme worlds.
GJ 367b is also special because it is the first exoplanet to be named by the public through the NameExoWorlds project, an initiative by the International Astronomical Union (IAU) that allows people to propose and vote for names for exoplanets and their stars. The name Tahay was chosen by a team from Chile, and it refers to a type of wildflower that only blooms for a few hours each year, alluding to the planet’s short orbital period. The star Añañuca was named after another type of Chilean wildflower.
Conclusion
GJ 367b is a fascinating planet that challenges our imagination and expands our knowledge of the diversity of worlds in the universe. It is also a reminder of how lucky we are to live on a planet that is just right for life, and how we should cherish and protect it.
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