Exam 11: Formation and Structure of Stars

Briefly describe the pressure-temperature thermostat in stars.

The nuclear reactions in a star's core burn steadily so long as the relationship between _____________ and_____________ is stable.

One of the factors that a large molecular cloud must overcome in order for gravitational contraction to begin is the thermal energy of the gas.

How do low-mass stars in the lower region of the main sequence produce their energy?

One of the factors that a large molecular cloud must overcome in order for gravitational contraction to begin is rotation of the gas cloud.

Hydrostatic equilibrium is the balance between _____________ and radiation _____________.

Where is the Trapezium found?

One of the major star forming regions in space is the Orion Nebula.

When a large gas cloud starts to collapse in a free-fall due to gravity, the cloud will ____.

Which atom is not a part of the CNO cycle?

The proton-proton chain for fusing hydrogen into helium is a much more complicated process than the CNO Cycle for fusing hydrogen into helium.

Stellar winds and _____ will eventually blow away the protostellar disk and remnant cocoons of a protostar apart.

Stars with masses equal to or less than 1.1 solar masses use the _____________ to convert H into He for their energy source.

Describe the concept of a "birth line" and identify where it falls on the H-R diagram.

During the main-sequence lifetime of a star of any mass, the core of the star will be composed mainly of ____.

When a large gas cloud starts to collapse in a free-fall due to gravity, it will start to cool down as it contracts because of the atoms fall inward.

Which trigger could start the gravitational contraction of a molecular cloud?

How do large-mass stars in the upper region of the main sequence produce energy?

Four of following are factors that must be overcome by a large molecular cloud before gravitational contraction can begin. Which one is the exception?