ASTR Chap 16 – Evolution of Low Mass Stars – Flashcards

The Sun will likely stop being a main-sequence star in:

When a star depletes its core supply of hydrogen, _________ causes the core to collapse while increased gas _________ is exerted on the atmosphere.

The evolutionary cutoff between low- and high-mass stars occurs at approximately:

As a main-sequence star burns its core supply of hydrogen, what happens?

When a spectral-type G2 star like the Sun leaves the main sequence:

Place the following evolutionary stages in order from youngest to oldest.

The percentage of hydrogen in the Sun's core today is roughly half of what it was originally.

The Sun will become a red giant star in about 5 billion years.

Using the data in the table below, identify the spectral type of a star that has a main-sequence lifetime of about 10 billion years.

Stars evolve primarily because they use up the fuel in their cores.

If a main-sequence star were gaining mass by being in an interacting binary system, what would happen to that star's luminosity and why?

If the Milky Way formed stars at approximately a constant rate over the last 14 billion years, what fraction of the M-type stars that ever formed in it can still be found as main-sequence stars today? Note that M-type stars have a mass of approximately 0.5 M.

Helium burns in the core of a horizontal branch star via _________ and produces _________.

For low-mass main-sequence stars in hydrostatic equilibrium, at any interior radius there exists a balance between the downward gravitational force at that radius and:

The more massive a star is, the more hydrogen it has to burn, and the longer its main-sequence lifetime lasts.

A main-sequence star is unique because:

As a subgiant star becomes a red giant, its luminosity increases while its temperature remains approximately constant. What does this mean?

Of stars with these masses, which star spends the longest time as a main-sequence star?

A Type I supernova has a luminosity of approximately:

A Type I supernova occurs when a white dwarf exceeds a mass of:

What are two ways that Type I supernovae can be produced?

One star in a binary will almost always become a red giant before the other because:

What ionizes the gas in a planetary nebula and makes it visible?

What is a planetary nebula?

During which phase of the evolution of a low-mass star does it have two separate regions of nuclear burning occurring in its interior?

The gas in a planetary nebula is composed of:

In a white dwarf, what is the source of pressure that halts its contraction as it cools?

As a white dwarf star gradually cools, its radius stays approximately constant. What is happening to the white dwarf's luminosity?

Asymptotic giant branch stars have high-mass loss rates because:

Asymptotic giant-branch stars have _________ luminosities, _________ radii, and _________ escape velocities.

Once the core of a low-mass main-sequence star runs out of hydrogen, fusion in the star stops until the core temperature is high enough for helium fusion to begin.

A star like the Sun will eventually become an electron degenerate white dwarf star.

Stars with masses similar to the Sun will lose approximately 30 percent of their mass before they become white dwarfs.

The Sun eventually could become a nova.

A 1M star in a binary system could create the following chemical element and eject it into the interstellar medium: