Astrophysicists recently discovered two exoplanets orbiting the star TOI-1453, located approximately 250 light years from Earth in the constellation Draco. This discovery provides a unique opportunity to study planets that are not present in our Solar System, but are common in the Milky Way.

The Constellation Draco and its Mythological Significance

The constellation Draco is one of the most prominent constellations in the northern hemisphere. It represents the dragon from Greek mythology that guarded the golden apples of the Hesperides, and which was slain by Hercules during one of his twelve labors. In the sky, Hercules is depicted standing with one foot on the dragon's head. Although this constellation is large, it does not have particularly bright stars; the brightest star is γ Draconis, also known as Etamin.

Characteristics of the star TOI-1453

TOI-1453 is a star that is somewhat smaller and cooler than our Sun. It is part of a binary system, which means it has a stellar companion with which it gravitationally interacts. Such systems provide valuable information on the formation and evolution of planetary systems.

Discovered exoplanets: Super-Earth and sub-Neptune

The first discovered planet, TOI-1453 b, is classified as a super-Earth. These planets are larger than Earth but smaller than the larger gas giants such as Neptune. TOI-1453 b has a radius 1.17 times that of Earth and orbits its star every 4.3 days. Its mass is less than 2.32 times that of Earth, indicating a rocky composition.

The second planet, TOI-1453 c, falls into the sub-Neptune category. These planets have masses and radii between that of Earth and Neptune. TOI-1453 c has a radius 2.22 times that of Earth and a mass of 2.95 Earth masses. It orbits the star every 6.6 days. Its low density suggests the presence of a thick atmosphere rich in hydrogen or an interior rich in water.

Methods for detecting exoplanets

The discovery of these exoplanets was achieved by a combination of two methods. The first is the transit method, where periodic decreases in the star's brightness are measured when a planet passes in front of it. The second method is radial velocity measurement, which detects changes in the star's speed caused by the gravitational influence of the planet. The combination of these methods allows for precise determination of the masses, radii, and orbital characteristics of the planets.

Orbital resonance and planetary migration

It is interesting that TOI-1453 b and TOI-1453 c have an orbital ratio close to a 3:2 resonance. This means that for every three orbits of the inner planet, the outer planet completes almost exactly two. Such resonances are often the result of orbital migration, a process during which planets change their initial orbits due to gravitational interactions with a disk of gas and dust or with other planets.

The significance of the discovery for future research

The discovery of these planets provides valuable targets for future studies of the atmospheric properties of exoplanets. In particular, TOI-1453 c, due to its low density, is an ideal candidate for detailed atmospheric studies that could reveal the presence of hydrogen, helium, or even water vapor. Such information is key to understanding the formation and evolution of sub-Neptunes.

The location of the star TOI-1453 in the constellation Draco

The constellation Draco stretches between the bright stars Arkut and Vega. Although it does not have particularly bright stars, its large area and interesting shape make it recognizable in the night sky. TOI-1453 is located within this constellation, which further increases interest in this area among astronomers and astronomy enthusiasts.

The discovery of exoplanets around the star TOI-1453 represents a significant step forward in our understanding of planetary systems beyond our Solar System. Studying these planets provides a unique opportunity to explore different types of planets and their atmospheres, which will contribute to a better understanding of the formation and evolution of planets in our galaxy.

Source: Institut d'Astrophysique et de Géophysique