A planet discovered outside our galaxy for the first time

 



Astronomers at Harvard University believe they have discovered, for the first time, a planet outside our galaxy, the BBC reported on October 25. The planet is said to be the size of Saturn and is located in the Messier 51 (M51) galaxy, 28 million light years from the Milky Way.


So far, no less than 5,000 exoplanets (or planets orbiting stars) have been discovered in the Milky Way. But none had been observed outside of our galaxy. A team of American astronomers has managed to obtain significant clues indicating the presence of one of them in the spiral galaxy M51. Results from NASA's Chandra X-ray Observatory show that the exoplanet is 28 million light years from our galaxy.


Astrophysicist Rosanne Di Stefano and her colleagues used the transit technique to detect the exoplanet. It consists of observing the decrease in luminosity of a star when an object passes in front of it (a planet for example). It confirmed the presence of 77.4% of the exoplanets known to date. Galaxy M51 contains a black hole (or neutron star) orbiting a star 20 times heavier than the Sun. "The X-ray transit they discovered using the Chandra data lasted about three hours, during which the ray emission fell to zero," the statement said in the journal Nature Astronomy. The exoplanet would be the size of Saturn and would orbit an X binary system, a normal star itself orbiting a neutron star or a black hole.


The finding remains an interpretation, and more data is needed to verify it. Unfortunately, the planet will not cross the black hole, where the neutron star, before 70 years, any observation is therefore impossible at the moment.

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