The TESS space telescope has discovered a new representative of exoplanets with ultra-short orbital periods. It was the hot super-Earthwolf 327b, whose iron core occupied nearly the entire volume of the planet. A preprint of this study is available at arXiv.org. Exoplanets with extremely short orbital periods (less than a day) are among the rarest types of planets ever discovered. Of the more than 5,000 confirmed exoplanets, only 130 are known. These are usually small (up to 2 Earth radii), very heated objects, and their existence does not correlate strongly with the metallicity of their parent star. They are more common in systems containing multiple planets, and the number of ultrashort-period exoplanets may depend on the type of star’s spectrum. Such exoplanets could form by the evaporation of Neptune’s atmosphere or by the orbital displacement of rocky planets. A team of astronomers led by Felipe Murgas of the University of La Laguna has reported the discovery of an ultrashort-period exoplanet, Wolf 327b, orbiting a red dwarf star 93 light-years from the sun. Initially, the planet’s intrastellar transit was observed by his TESS space telescope, and the discovery was later confirmed by observational data from ground-based observatories. The parent star is spectral type M2.5, has a mass 0.4 times the mass of the Sun, and is 4.1 billion years old. The exoplanet, with a radius of 1.24 times that of Earth and a mass 2.53 times that of Earth, orbits with a period of 0.573 days and has an average volume density close to that of iron. Wolf 327b is therefore a super-Earth with an iron core that could have a mass up to 93 percent of the planet’s total mass and a radius up to 78 percent of the planet’s radius, making it similar to exoplanet K2-229b. similar. The remaining mass resides within the mantle, along with small amounts of water and volatile materials. Exoplanets likely do not have atmospheres. He may have lost these in the past. The planet’s equilibrium temperature is estimated to be 996 Kelvin.

source: https://arxiv.org/abs/2401.12150