On a Source of Systematic Error in Absolute Measurement of Galactocentric Distance from Solving for the Stellar Orbit Around Sgr A*

Understand

Eisenhauer et al.

• (2003, 2005) derived absolute (geometrical) estimates of the distanceto the center of the Galaxy, $R_0$, from the star S2 orbit around Sgr A* on the assumption that the intrinsic velocity of Sgr A* is negligible.
• This assumption produces the source of systematic error in $R_0$ value owing to a probable motion of Sgr A* relative to the accepted velocity reference system which is arbitrary to some extent.
• Eisenhauer et al.