Question

question 13 (1 point)
the mass of a star - how much material it contains - is one of its most important characteristics. if we know a stars mass we can estimate _?_
o a how long it will shine
o b the precise distance from earth
o c the exact composition

question 14 (1 point)
a characteristic of star measurement is _?_
o a core temperature
o b physical composition
o c luminosity
o d all of the above
o e none of the above

question 15 (1 point)
all you need to make a star is _?_
o a sodium, gravity, and time
o b krypton, gravity, and time
o c hydrogen, gravity, and time
o d potassium, gravity, and time

Explanation:

Question 13

The mass of a star affects its lifespan. More massive stars have shorter lives as they burn through their fuel (nuclear fusion) faster. Distance from Earth is measured via parallax and other methods, not directly from mass. Composition is determined by spectroscopy.

Core temperature (affects fusion rate), physical composition (elements present), and luminosity (brightness) are all measured characteristics of stars. So all these are part of star measurement.

Stars form from clouds of gas (mostly hydrogen). Gravity pulls the gas together, and over time (with nuclear fusion starting when conditions are right in the core), a star is born. Sodium, krypton, and potassium are not the primary starting materials for star formation.

Answer:

A. how long it will shine

Question 14