Exam 13: The Lives of Stars From Birth Through Middle Age

The stars of a cluster are plotted on an H-R diagram. It is seen that the main sequence is well populated at the upper end and that there are many stars above (and to the right of) the main sequence at its lower end. What can be concluded about the age of this cluster?

Why does the core of the Sun contain more helium and less hydrogen than the surface of the Sun?

The star Zeta Pegasi (in the constellation Pegasus, the Flying Horse) has a spectral luminosity class of B8 V, which gives it a surface temperature of about 11,000 K. According to Table 13-2 in the text, the expected main-sequence lifetime of Zeta Pegasi is

In a Cepheid variable, what happens to make the temperature decrease?

About how long did the Sun spend in the protostar phase of its life?

A T Tauri star is a

The space between stars is known to contain

Long-exposure color photographs of the night sky often show regions that glow red, such as the Rosette Nebula in Figure 13-8 in the text. This distinctive red color is caused by the

For an astronomer, what is the significance of the turnoff point in the Hertzsprung-Russell diagram of a star cluster?

If one were to look for a protostar in its early stages, one would observe in which wavelength region?

Which of these common molecules found in interstellar space contains nitrogen atoms but no oxygen?

Where in the universe would one look for a protostar?

The Orion Nebula is a

How long does core helium burning last in a star compared with core hydrogen burning?

How do the stars in a star cluster change with time?

In an open cluster, the sizes of some of the lower-mass stars may have been limited when the surrounding material the stars were accreting was blown away by ultraviolet radiation. What is the source of this UV radiation?

Which of these methods has NOT yet been used to study the material of the interstellar medium?

The distinctive color of a reflection nebula is

Which of these features do astronomers NOT have direct evidence for brown dwarfs?

What scientific method is used to observe the pulsation in size of a Cepheid variable star?