astronomy ch. 15

A star leaves the horizontal branch in the HR diagram when

it runs out of helium at its core.

When a star first moves off the main sequence,

its surface temperature drops and its brightness first stays about the same and then increases.

When the temperature of a gas increases, its molecules

move faster

Which of the following particles would be attracted to a neutron through the strong force?

proton

Our Sun is a type G2V star on the main sequence. As it ages and uses up its fuel we expect it to

remain a G2V star until it leaves the main sequence.

When a red giant star begins to burn helium, it

returns part way to the main sequence in an HR diagram.

The period of a proto-star's evolution when its size and brightness decrease just before the ignition of nuclear reactions in its core is called

the Tau Tauri phase.

The mass of a carbon atom is 12.00amu while the mass of a helium-4 atom is 4.003amu. If a gamma ray photon splits a carbon atom into three Helium atoms, how much energy is converted into mass?

0.009amu

The diameter of a white dwarf star might be

10,000 miles

Which of the following star-like objects would most likely be considered to be a brown dwarf?

Gliese 229B, luminosity and temperature both below type M9V.

For a star to give rise to a Nova, the star must be

a member of a multiple star system.

An atom of ordinary hydrogen consists of a proton and

an electron

Which of the following particles would be electrically attracted by a positron?

an electron

The onset of Helium burning at the core of a star normally begins with

an explosion in the helium core.

Because of the electrical repulsion between atomic nuclei, nuclear fusion happens only

at high temperatures.

When nuclear fusion reactions stop in a star similar to our own Sun, the star

becomes a white dwarf.

The light from a new-born white dwarf star will most likely be

blue

A star leaves the main sequence when

it runs out of Hydrogen at its core.

The mass of Betelgeuse is about 20 times the mass of our own Sun. Our Sun is expected to have a total life span of about 10 billion years. The life span of Betelgeuse is expected to be

much shorter.

Which of the following particles has almost the same mass as a proton?

neutron

Electron degenerate matter is matter in which

the electrons are touching each other so that they cannot be compressed.