Astronomy 122 Exam 3

Front 1

Clouds of nebular gas are

Back 1

90% H, 9% He, 1% other

Front 2

Collapse of dust and gas is initiated by

Back 2

Shock waves from:
stellar wind of nearby heavy stars
supernova explosion

Front 3

New star formation is associated with

Back 3

Open/galactic clusters
OB associations
HII regions (regions of ionized gas)
ex: Orion nebula

Front 4

Stellar association

Back 4

Loosely bound group of new-born stars

Front 5

Absorption nebula

Back 5

Cloud of dust and gas which obscures more distant light ex: Horsehead nebula

Front 6

Reflection nebula

Back 6

Cloud of dust illuminated by stars (blueish)
ex: Pleiades

Front 7

Emission nebula

Back 7

Glowing from excitation caused by nearby stars
ex: Orion nebula

Front 8

Brown dwarf

Back 8

Failed star. If the mass is less than 0.08 Msun, it never gets hot enough for thermonuclear fusion

Front 9

10 x 10^6 K

Back 9

Proton-proton chain

Front 10

20 x 10^6 K

Back 10

CNO cycle

Front 11

100 x 10^6 K

Back 11

Triple alpha

Front 12

600 x 10^6 K

Back 12

Carbon-helium fusion

Front 13

10^9 K

Back 13

Carbon burning

Front 14

Main sequence phase ends when

Back 14

Core hydrogen burning ends

Front 15

Helium burning

Back 15

When core reaches 100,000,000 K, helium fuses to carbon (triple alpha process)

Front 16

Helium flash

Back 16

Runaway helium fusion initially for stars with mass less than 3Msun

Front 17

Red giant

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Very bright, enlarged star
ex: Betelgeuse

Front 18

Planetary nebula

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25%-60% of the star is ejected, white dwarf may soon appear in the middle

Front 19

White dwarf

Back 19

Spent low-mass star, cools slowly, no longer generate energy

Front 20

Chandresekhar Limit

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Less than 1.4 Msun, degenerate electron pressure, density = 10^9 kg/m^3

Front 21

Black dwarf

Back 21

After the white dwarf cools and dims. A cold, dense, burned-out ember in space

Front 22

Type I supernova

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Binary system, carbon-detonation supernova, white dwarf grows from accretion of material from companion, eventually exceeding Chand mass limit

Front 23

Type II supernova

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Single massive star, core-collapse supernova, massive star expends its fuel supply, ending with iron core, and collapses and explodes. Not in Milky Way

Front 24

Neutron stars

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Extremely dense stellar matter, diameter of 30 miles

Front 25

Pulsars

Back 25

Pulsating radio source produced by rapidly rotating N-star

Front 26

Close binaries

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Stars separated by few stellar diameters

Front 27

Critical surface

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figure eight-shaped boundary around star defining gravity domain. Two lobes called Roche lobes. If it collapses it will result in mass transfer

Front 28

Blue stragglers

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Stars found in globular star clusters which have not evolved as much as comparable massive stars. Results from mergers of lower mass stars which delayed the normal evolution of the massive star

Front 29

Neutrinos

Back 29

No charge, very little particle mass, hardly interacts with anything, very hard to detect, travels at nearly the speed of light

Front 30

Pauli Exclusion Principle

Back 30

You can't have two things (electrons) in the same place at the same time

Front 31

Horizontal Branch

Back 31

Post-helium flash stars on the H-R diagram

Front 32

Young clusters

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Metal rich. Population I. Open/galactic cluster

Front 33

Old clusters

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Metal poor. Population II. Globular cluster