Question

what is not part of the criteria for a \dwarf planet\?
must have cleared its orbit of other bodies
must be spherical
must not be a satellite
must orbit a star
question 39 2 pts
by observing the wavelengths (locations) of the missing lines (dark lines) in the spectrum of a star, what can you determine about that star?
its size
its color
its mass
its composition
question 40 2 pts
what is the closest star system to the solar system?
sirius
andromeda
alpha centauri

Explanation:

1. For the dwarf - planet question: A dwarf planet does not need to have cleared its orbit of other bodies. Planets are required to have cleared their orbits, but dwarf planets do not meet this criterion.
2. For the star - spectrum question: Each element has a unique set of spectral lines. By observing the wavelengths of the missing lines (absorption lines) in a star's spectrum, we can determine the elements present in the star, thus its composition.
3. For the closest - star - system question: Alpha Centauri is the closest star system to the Solar System. Sirius is a single star and is farther than Alpha Centauri, and Andromeda is a galaxy, not a star system close to the Solar System.

Answer:

1. must have cleared its orbit of other bodies
2. Its composition
3. Alpha Centauri