Source 2 (abbreviated
S2), also known as
S0–2, is a star that is located close to the radio source
Sagittarius A*, orbiting it with an orbital period of 15.56 ± 0.35 years and a
pericenter distance of 17
light hours (18
Tm or 120
AU) — an orbit with a period only about 30% longer than that of
Jupiter around the
Sun, but coming no closer than about four times the distance of
Neptune from the
Sun. As of 2002, its mass was initially estimated by the European Southern Observatory (ESO) to be approximately (Fifteen times our Sun's mass).