What happens when a star like the sun exhausts its core hydrogen ...

[segrsyd]

What happens when a star like the sun exhausts its core hydrogen supply?
 
  A) Its core contracts, but its outer layers expand and the star becomes bigger and brighter.
  B) It contracts, becoming hotter and brighter.
  C) It contracts, becoming smaller and dimmer.
  D) Its core contracts, but its outer layers expand and the star becomes bigger but cooler and therefore remains at the same brightness.
  E) It expands, becoming bigger but dimmer.

Question 2

The Doppler technique can be used to measure the eccentricity of a planet's orbit by
 
  A) measuring the amount by which the starlight is reduced when the planet transits.
  B) measuring the asymmetries in the velocity curve.
  C) measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak, and using Newton's version of Kepler's Third law.
  D) measuring the speed at which the star orbits the mutual center-of-mass of the star and planet, and using Newton's theory of gravity.

[amcvicar]

Answer to Question 1

A

Answer to Question 2

B

[segrsyd]

Excellent

[shailee]

Gracias!