The location of putative planet M51-ULS-1b.X-ray: NASA/CXC/SAO/R. DiStefano, et al.; Optical: NASA/ESA/STScI/Grendler
Astronomers identified the possible exoplanet, M51-ULS-1b, because its transit blocked X-ray radiation from the remnant of a dead star — either a neutron star or a black hole — near the heart of the spiral galaxy M51, 23 million light years away. The planet is believed to be orbiting in a binary star system….