Answer:
Exoplanets
Step-by-step explanation:
Exoplanets (also known as extrasolar planet) are other planets outside the solar system. Exoplanets are of different categories, some of them orbit around other stars while some called rogue planets orbit the galactic center.
There are more than 4000 exoplanets which have been discovered, these planets have been discovered using the process of Transit photometry and Doppler spectroscopy.