What is the standard reference frame used when quoting the measured velocity of a star relative to the Milky Way?

Answer

Relative to the Sun

When astronomers discuss the velocity of a nearby star, the speed quoted is almost invariably its velocity relative to the Sun. This is a crucial distinction because the Sun itself is not stationary; it orbits the center of the Milky Way galaxy at a substantial speed, often cited near $220 ext{ km/s}$ due to the overall galactic rotation. Therefore, the measured velocity represents the difference between the Sun's orbital velocity and the star's slightly different orbital velocity. If the reference point were changed, such as observing from a distant galaxy or even relative to the Galactic Center, the calculated space velocity for the Sun and all neighboring stars would change significantly, highlighting the relative nature of these measurements.

What is the standard reference frame used when quoting the measured velocity of a star relative to the Milky Way?

Related Questions

What mathematical relationship connects the total space velocity (V) using the radial velocity ($V_r$) and tangential velocity ($V_t$)?When measuring radial velocity ($V_r$), what spectral phenomenon indicates a star is moving toward the observer?What essential measurement, expressed in angular units like arcseconds per year ($ ext{arcsec}/ ext{year}$), is required to define tangential velocity ($V_t$)?What is the standard reference frame used when quoting the measured velocity of a star relative to the Milky Way?If a star’s distance ($d$) estimate is incorrect by a factor of two, how does this error propagate into the calculated tangential velocity ($V_t$)?What observation, related to the Doppler effect, signifies that a star has a negative radial velocity ($V_r$)?What astrophysical insights can researchers gain by analyzing the velocity distributions of large groups of stars within the Milky Way?How do the random motion components typically compare between ancient, halo stars and younger stars concentrated in the galactic plane?What inherent advantage in precision does the measurement technique for radial velocity ($V_r$) offer over tangential velocity ($V_t$) determination?What study, foundational to astrophysics, involves determining the speed and direction of stars within the Milky Way?
Spaceastronomymovementvelocitystar