Monday, December 6, 2021

Hot, dense iron exoplanet discovered 31 light-years from Earth

 Called GJ 367b, it's about the size of Mars and takes just 8 hours to make a complete loop around its star; meet this curious star An exoplanet half Earth's mass and slightly larger than Mars orbits a red dwarf just 31 light-years from us. The discovery of the star, called GJ 367b, represents an advance in the search for a “second Earth”, since, even being such a small planet, scientists were able to determine several of its characteristics.

lPlanet detection involves a team of 78 researchers led by the Planetary Research Institute of the German Aerospace Center (DLR). To find data such as the mass and size of GJ 367b, which has a diameter of about 9,000 miles, astronomers used two main methods. “One was to measure the minimum dip in the light emitted by the star as the planet passed in front of it.

 This was done using data from NASA's Transiting Exoplanet Survey Satellite (Tess), "explains Vincent Van Eylen, a researcher at University College London, England, and co-author of the article published this Thursday (2), in the scientific journal Science . The other method is to infer the planet's mass from the effect it had on the star's motion. 

"This movement was slight - at a rate of 80 degrees per second, it was no more than walking speed - so it's amazing that we can detect this tiny movement at 31 light-years away," Eylen points out. After determining the radius and mass of GJ 367b, scientists managed to classify it as an underground, a category of exoplanets that have a mass less than Earth. In addition, the newly discovered star has an ultra-short period, meaning that it makes a complete circle around its star in less than 24 hours. More precisely, its translation movement only lasts 8 hours.

 We already know some of these [planets], but their origins are unknown,” says Kristine Lam, a researcher at the DLR and leader of the study. "By measuring how accurate fundamental properties of the planet, we can get a glimpse into the formation of the system and the history of evolution." Also through measurements of radio and mass, astronomers were able to hypothesize about the interior of GJ 367b. As a rocky exoplanet, with low mass and high density, scientists believe that the planet is dominated by an iron core. "These properties are similar to those of Mercury, with its disproportionately large iron and nickel core, unlike other rock bodies in the Solar System", compares Szil√°rd Csizmadia, also a co-author of the study and a researcher at the DLR.

Another aspect that could be estimated about the planet is its exposure to radiation. Because it is so close to its star, the levels can be 500 times higher than those experienced on Earth. In addition, its surface can reach a temperature of 1,500 °C - a temperature at which all metals and stones can be melted. Another aspect that astronomers are aiming at finding the exoplanet GJ 367b is the star it orbits, GJ 367. Classified as a red dwarf, it is about half the size of the Sun and cooler than it, which makes it easier the detection and characterization of planets. Red dwarfs are one of the most common objects in our sidereal neighborhood and are among the top targets for exoplanet research.

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