In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

Observations of the star S2 in orbit around Sagittarius A * were used to show the presence of the Milky Way 's central supermassive black hole .
Observations of a number of stars orbiting around Sagittarius A * , most notably the star S2 , have been used to provide evidence for the presence of , and produce data about , the Milky Way 's hypothesized central supermassive black hole , and have led some scientists to conclude that Sagittarius A * is beyond any reasonable doubt the site of that black hole .