Astronomy 20, Stellar Evolution

cooled off white dwarfs that no longer glow visibly

What are black dwarfs?

hydrogen

Which of the following elements contained in your body is NOT formed in the cores of stars during thermonuclear fusion?

Helium builds up in the core, while the hydrogen burning shell expands

What inevitably forces a star like the Sun to evolve away from being a main sequence star?

red giant

The "helium flash" occurs at what stage in stellar evolution?

that the collapsed companion transferred mass to Sirius A.

That brighter Sirius A weighs 3 solar masses, but the white dwarf Sirius B is only about one solar mass implies:

it builds up a core of inert helium.

A solar mass star will evolve off the main sequence when

in hydrostatic equilibrium

When a star's inward gravity and outward pressure are balanced, the star is said to be

asymptotic giant branch

Refer: What is the name of the path between the points labeled 10 and 11?

as a main sequence star

A star (no matter what its mass) spends most of its life

a helium white dwarf

What is the unusual result of mass transfer in the Algol binary system?

the star grows more luminous.

During the hydrogen shell burning phase

9

Refer: At what numbered point on the graph above does the helium flash occur?

planetary nebula

Refer: What is the name of the path between the points labeled 11 and 12?

white dwarf

Refer: What is the name of the path between the points labeled 13 and 14?

it generates more heat and its core eventually collapses very suddenly.

A high-mass star dies more violently than a low-mass star because:

blue stragglers

Which stars in globular clusters are believed to be examples of mergers?

the main sequence turnoff

What characteristic of a star cluster is used to determine its age?

it is burning both hydrogen and helium.

A star is on the horizontal branch of the H-R diagram. Which statement is true?

massive blue main sequence stars

The brightest stars of a young open cluster will be

Roche Lobe.

Mass transfer in binaries occurs when one giant swells to reach the

the ejected envelope, often bipolar, of a red giant surrounding a stellar core remnant

What is a planetary nebula?

red supergiants

In globular clusters, the brightest stars will be

because they can also have strong stellar winds

Isolated main-sequence stars as massive as 10 to 12 times the mass of the sun bay still manage to avoid going supernova. Why?

red giant branch

Refer: What is the name of the path between the points labeled 8 and 9?

horizontal right

Which of the following best describes the evolutionary track of the most massive stars?