The one that was the first exoplanet to be discovered around a star similar to our Sun (which happened in 1995) is the protagonist of this milestone in the world of astrophysics. Its name is 51 Pegasi b and it is a gaseous planet located 51 light years from Earth in the constellation of Pegasus.
Thanks to the 3.6-meter telescope of the European Southern Observatory located at the La Silla Observatory (Chile), which has the instrument called Harps, designed to search for extrasolar planets, this discovery has been possible. It is the first time that a telescope, in addition to being medium in size, is capable of directly detecting light from a planet in another solar system. A direct signal from another planet had never been captured until now. This method, based on the Doppler effect, has revealed the size, orbit and atmosphere of 51 Pegasi b, which will allow the future study of other exoplanets .
Thus, the new observations show that this exoplanet has half the mass of Jupiter but a size greater than this (due to the amount of light it reflects from its star) and an orbit – seen from Earth – with an inclination of nine degrees. .
“ This type of technique is of great importance, because it allows us to measure the actual mass and inclination of the planet’s orbit. It also allows us to estimate its reflectance, which can be used to infer the composition of both the surface and the atmosphere of a planet, ”explains Jorge Martins, leader of the study.
The study, which has been published in the journal Astronomy & Astrophysics , is expected to be the first of many upcoming works using this technique but with even larger telescopes. The 8.2-meter Very Large Telescope (VLT), also located in Chile, will be the next to make similar observations. “And with the E-ELT, the European Extremely Large Telescope, we hope to be able to characterize an exoplanet like Earth, ” says Martins. For this moment, we will have to wait until 2024, since at the moment, this terrestrial telescope with a diameter of 39 meters, is in the middle of the construction phase.
