Exam 13: Star Stuff

You discover a binary star system in which one member is a 15 solar mass main- sequence star and the other star is a 10 solar mass giant star. Why should you be surprised, at least at first?

Which element is the dead end for cores of the most massive stars?

What is a helium flash?

What eventually halts the gravitational collapse of an interstellar gas cloud that forms an object that is not massive enough to become a star?

Why does a star grow larger after it exhausts its core hydrogen?

Lithium, beryllium, and boron are elements with atomic number 3, 4, and 5, respectively. Even though they are three of the five simplest elements, why are they rare compared to many heavier elements?

The point labelled iii corresponds to

Which of the following statements about degeneracy pressure is not true?

Which is more common: a star blows up as a supernova, or a star forms a planetary nebula/white dwarf system?

What did Carl Sagan mean when he said that we are all "star stuff"?

Although some photographs show what looks like jets of material near many young stars, we now know that these "jets" actually represent gas from the surrounding nebula that is falling onto the stars.

Helium fusion results in the production of

Why is a 1 solar- mass red giant more luminous than a 1 solar- mass main sequence star?

In any star cluster, stars with lower masses greatly outnumber those with higher masses.

(Use diagram of abundance vs atomic number)What process best explains the observed pattern of abundances of elements with atomic numbers between 6 and 20?

This diagram represents the life track of a 1 solar mass star. Refer to the life stages labeled with roman numerals. Which stage lasts the longest?

Consider a large molecular cloud that will give birth to a cluster of stars. Which of the following would you expect to be true?

What percentage of a star's total lifetime is spent on the main sequence?

Do you think it is possible that a 1.5- solar- mass red giant could harbor an advanced civilization? Explain your reasoning.

This schematic shows the number of stars formed in each mass range for each star more massive than 10 MSun. What is the mass range of the most common stars?