Question

How do astronomers usually determine the sizes of exoplanets?

(a) Using the transit method, from the depth of the eclipse.
(b) Using the transit method, from the duration of the eclipse.
(c) Using the Doppler method, from the orbital period.
(d) Using the Doppler method, from the radial velocity.
(e) Using the combination of the transit method and the Doppler method.

Answer 1

The sizes of exoplanets are usually determined using a combination of the transit method and the Doppler method. The transit method involves measuring the dimming of a star when a planet crosses in front of it, and the Doppler method allows us to estimate the mass of the planet.

Step-by-step explanation:

The sizes of exoplanets are usually determined using a combination of the transit method and the Doppler method. The transit method involves measuring the slight dimming of a star when a planet crosses in front of it. The depth of the eclipse, which is the amount of starlight obscured, gives us information about the size of the planet.

The Doppler method, on the other hand, allows us to estimate the mass of a planet by measuring the radial velocity of the star caused by the gravitational pull of the planet. By combining information from both methods, astronomers can determine both the size and mass of an exoplanet, and calculate its average density.