An Etymological Dictionary of Astronomy and Astrophysics

A → main sequence→ B-type star that orbits the → supermassive black hole candidate → Sgr A* in the → Galactic center. The star S2, which is bright enough for making detailed measurements, has a highly elliptical, 16-year-period orbit around Sgr A*. Near → pericenter at 120 → astronomical units, ~ 1400 → Schwarzschild radii, the star has an orbital speed of ~ 7650 km s^-1, such that the first-order effects of → special relativity and → general relativity have become detectable with current capabilities (Auber et al., 2018, A&A 615, L15).

See also: → star.