Blink speed dating au
The radial-velocity method can be used to confirm findings made by the transit method.
When both methods are used in combination, then the planet's true mass can be estimated.
The radial-velocity method measures these variations in order to confirm the presence of the planet using the binary mass function.
The speed of the star around the system's center of mass is much smaller than that of the planet, because the radius of its orbit around the center of mass is so small.
(For example, the Sun moves by about 13 m/s due to Jupiter, but only about 9 cm/s due to Earth).
If a planet crosses (transits) in front of its parent star's disk, then the observed visual brightness of the star drops by a small amount; depending on the relative sizes of the star and the planet.
Any planet is an extremely faint light source compared to its parent star.
For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it.
The second reason is that low-mass main-sequence stars generally rotate relatively slowly.
Fast rotation makes spectral-line data less clear because half of the star quickly rotates away from observer's viewpoint while the other half approaches.