Radiaalnopeusmenetelmä

Radiaalnopeusmenetelmä, also known as the radial velocity method or Doppler spectroscopy, is a technique used to detect exoplanets by measuring the slight wobble of a star caused by the gravitational pull of an orbiting planet. This wobble is detected as a shift in the star's light spectrum due to the Doppler effect. As the star moves towards an observer, its light is blueshifted, and as it moves away, its light is redshifted. By observing these periodic shifts in spectral lines over time, astronomers can infer the presence and mass of an orbiting planet, as well as its orbital period.

The radial velocity method is particularly effective at detecting massive planets orbiting close to their stars, as these planets exert a stronger gravitational influence and produce a larger, more easily detectable wobble. It has been a cornerstone of exoplanet discovery since the late 1990s and has led to the identification of thousands of exoplanets. While it cannot directly image the planet, it provides crucial information about the planet's minimum mass and its orbital characteristics. Further observations and analysis can help refine these estimates and even provide clues about the planet's atmosphere. The precision of this method has steadily improved with advancements in telescope technology and spectrographs.