Astronomy 128 Homework 5 Printable Version

1) Identify the location and process that forms each of the following types of element.

Locations might be , high mass stars, low mass stars, supernovae etc. Effects of the Big Bang are identified separately because you have not studied it yet)

Element(s)	Location where formed	Process (name of the nuclear process)
Hydrogen	Big Bang, before stars	xxxxxxxxxxxxxxxxxx
Helium	______ and Big Bang
Carbon 12
Oxygen 16
Sulfur 32
Iron 56
Cobalt 60, Bismuth 209
Uranium 238, Plutonium 242
Bismuth 209

2) What causes the radiation from a pulsar to vary?

3) How do we know that a pulsar is small?

4) Which is has a bigger radius, a neutron star, a black hole with mass of a couple of solar masses or a white dwarf?

5) What is the evidence that gamma ray pulses are parts of distant galaxies?

6) Why is it harder to find the shape of our galaxy, the Milky Way, than to find the shape of an external galaxy like the Andromeda Galaxy?

7) How do we find the rotation of the far side of our galaxy ?

8) Which is brighter, a Cepheid variable star that pulses every 3 days or one that pulses every 15 days? If a Cepheid variable pulses every 10 days, how many times as bright as the Sun is it?

10) Where in our Galaxy would you look for the following?

a) Young, massive stars

b) Dust

c) Globular Clusters

d) Galactic Clustsrs

e) Emission nebulae

11) Describe the evidence that there is a massive Black Hole at the center of the Milky Way.

12) What are spiral arms made of?

13) What is the evidence that our Galaxy has more mass than what we can find in the stars and the gas?

14) What is a MACHO?

15) How do we use gravitational lensing to detect MACHO’s?