How do astronomers measure the size and mass of exoplanets?

Astronomers employ various techniques to measure the size and mass of exoplanets, planets that exist beyond our solar system. These methods include transit photometry, radial velocity, and direct imaging, each offering valuable insights into the characteristics of these distant worlds.

1. Transit Photometry:

Transit photometry involves measuring the dip in a star's brightness as an exoplanet passes in front of it. By observing these periodic dimming events, astronomers can determine the size of the exoplanet relative to its host star.

2. Radial Velocity:

Radial velocity measurements track the wobble of a star caused by the gravitational pull of an orbiting exoplanet. This method helps scientists calculate the mass of the planet based on its effect on the star's motion.

3. Direct Imaging:

Direct imaging involves capturing actual pictures of exoplanets. While challenging due to the brightness of host stars, this method provides crucial information about the size and composition of the planets.

By combining data from these techniques, astronomers can create a more comprehensive understanding of exoplanets, advancing our knowledge of the vast array of worlds beyond our own.