Question

The Radial Velocity (Doppler) technique only provides a measure of the minimum mass of a planet because

A) only a small part of the planet's motion is measured.
B) without a transit observation, the size and therefore density of the planet are unknown.
C) we do not know the exact composition of the planet.
D) only the motion of the star toward the observer is measured, not the full motion.
E) we do not have the technology to make a direct image of a planet yet.

Answer 1

The Radial Velocity (Doppler) technique provides a measure of the minimum mass of a planet due to limited observations of its motion, lack of transit observations, incomplete knowledge of composition, restricted measurement of star's motion, and absence of technology for direct imaging of planets.

Step-by-step explanation:

The Radial Velocity (Doppler) technique only provides a measure of the minimum mass of a planet because:

1. Only a small part of the planet's motion is measured.
2. Without a transit observation, the size and density of the planet are unknown.
3. We do not know the exact composition of the planet.
4. Only the motion of the star toward the observer is measured, not the full motion.
5. We do not have the technology to make a direct image of a planet yet.

The Radial Velocity (Doppler) technique relies on observing the changes in a star's radial velocity caused by the gravitational pull of a planet. This method can only provide information about the minimum mass of a planet because it does not account for factors such as the planet's size, density, composition, and the full range of its motion. The Radial Velocity (Doppler) technique measures the wobble of a star caused by the gravitational influence of an orbiting planet. While it can provide information about the minimum mass of the planet (since it depends on the amplitude of the star's radial velocity curve), it does not directly provide information about the size or density of the planet. Without additional data, such as observations of a transit (when the planet passes in front of the star), the physical characteristics of the planet, such as its size and density, remain uncertain. Option B correctly reflects this limitation of the Radial Velocity technique.