Life Cycle of a Star

What is the life cycle of a low mass star?

Stellar nebula, protostar, low mass average star, red giant, planetary nebula, white dwarf, black dwarf

What is the life cycle of a high mass star?

Stellar nebula, protostar, high mass average star, super red giant, supernova, neutron star, black hole

What is nuclear fusion?

When the electrons are stripped off of the atoms, creating plasma. The nuclei in the plasma moves faster and faster, then crashes into each other and fuses, becoming a star.

What does the x axis on a HR diagram measure?

Surface temperature

What does the y axis on a HR diagram measure?

Luminosity

What does it mean if the luminosity of a star is 1?

It is the same brightness as the sun

What are the four types of stars on an HR diagram?

Dwarfs, main sequence stars, giants, supergiants

If a star is more towards the top of an HR diagram, is it bigger or smaller?

Bigger

What color is a star with a very high temperature (30,000-50,000 K)?

Blue

What color is a star with a low temperature (2,000-3,500 K)?

Red

What is the color order of stars from least hot to most hot?

Red, reddish orange, yellow, yellowish white, white, blue or bluish white, blue

What are the four properties HR diagrams use to classify stars?

Temperature, luminosity, size, age

As a star changes color from red to blue, describe what happens to its surface temperature?

The star is becoming hotter

Which type of star is dimmer than the Sun?

Dwarf

What is the relationship between luminosity and temperature for stars on the Main Sequence?

The cooler stars are dimmer and the hotter stars are brighter

What is the relationship between the temperature of a star and that star’s lifetime?

The hotter the star, the shorter its lifetime. The cooler the star, the longer its lifetime.

What is the relationship between a star’s mass and its luminosity?

The more mass a star has, the more luminosity it has.

What is a stellar nebula?

A region of cosmic dust and gas where stars are born

What is a protostar?

A baby star

What happens when a high or low mass star is in the average stage?

It survives on hydrogen for millions-billions of years until it runs out. The Sun is in this stage now.

What is a red giant?

A star with high luminosity and low temperature. The outer layers expand outwards and the core contracts inwards. The star is dying.

What is a planetary nebula?

A diffused cloud caused by a star shedding its outer layers.

What is a white dwarf?

The densest form of matter in the universe aside from neutron stars. They have no fuel left to burn so they radiate their remaining heat into space for billions of years until it runs out.

What is a black dwarf?

Cold, dark mass that doesn’t radiate at all.

What is a super red giant?

A larger and brighter type of red giant. Super red giants have the largest volume out of any star.

What is a supernova?

The explosion of a star when the nuclei overcome gravity and the core shoots out. If the remnant is 1.4 to 3 times as big as the Sun, it will become a neutron star.

What is a neutron star?

The core of a star that remains after a supernova. It is basically a dense ball of neutrons and is the densest form of matter in the universe, causing it to have strong gravitational and magnetic fields.

What is a black hole?

Black holes are so dense that even light can’t escape the gravity. Black holes are formed when the core of a massive star has roughly 3 times the mass of the Sun after a supernova, causing it to be swallowed by its own gravity.