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Connexus 8: Science > Astronomy: The Stars (Unit 1) > Flashcards

Astronomy: The Stars (Unit 1) Flashcards

1
Q

Constellation Definition

A

A group of stars forming a recognizable pattern

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2
Q

When did Astronomers understand that the stars in the night sky were like our sun? After which invention? After which discovery?

A

The 17th century, after the invention of the telescope and the discovery of the laws of gravity and motion

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3
Q

In the 19th century, the use of photography and spectroscopy allowed astronomers to understand what about stars?

A

Their movement, composition, temperature, and life cycle

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4
Q

How do astronomers today learn about the invisible radiation emitted by stars today?

A

They use radio telescopes and satellites that gather microwave data

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5
Q

What information does the Hubble Space Telescope provide?

A

The Hubble Space Telescope allows astronomers to take images of star systems no one can see from Earth’s surface

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6
Q

What are the characteristics of a star?

A

Temperature, size, color, brightness, and composition

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7
Q

What are stars made up of?

A

Stars are balls of gas, made up mostly of helium and hydrogen, but they do contain small amounts of heavier elements as well

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8
Q

Are all stars in a constellation the same distance from Earth?

A

A constellation can have stars ranging from 26 light years away to several thousand light years away, but since we see them in the same part of the sky, we think they are close together

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9
Q

How do we classify specific constellations?

A

Based on what they remind us of

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10
Q

How do the patterns and shapes in constellations help us identify them?

A

The patterns and shapes of constellations remind us of things like animals and people, which help us identify the constellation in the sky

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11
Q

What does the Big Dipper look like?

A

A big spoon or ladle

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12
Q

How does the location and characteristics of stars in a constellation help with identification?

A

The location of stars and the characteristics of the specific stars in the constellation help with identification

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13
Q

How does the location and characteristics of stars help people identify the Big Dipper?

A

You can identify the Big Dipper by its brightest star Polaris, also called the North Star

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14
Q

What are stars?

A

Stars are giant, spherical collections of plasma that generate light and heat because of the nuclear reactions taking place within them

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15
Q

Where was the carbon that makes up all living things made?

A

Small nuclei fuse together to form heavier elements inside stars — a process that releases large quantities of energy. This means that the carbon that makes up all living things on Earth was formed inside ancient stars

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16
Q

How do newer star forming today differ with older stars that formed when the universe was young?

A

New stars forming today include higher percentages of heavier elements than stars that formed when the universe was young

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17
Q

Plasma Definition

A

A state of matter in which electrons separate from atomic nuclei, but remain balanced in number

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18
Q

What do all stars differ in? (Characteristics)

A

Stars differ in their brightness, color, surface temperature, volume (size), magnetic field strength, and metallicity (elements above helium within the sun)

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19
Q

What do astronomers often compare stars to?

A

The sun; for example, the masses of other stars are given in solar masses

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20
Q

What is the solar mass of Alpha Centauri?

A

1.08 solar masses

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21
Q

What is the solar mass of Betelgeuse?

A

Betelgeuse, one of the brightest stars in the sky, is about 20 solar masses

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22
Q

True or False: Energy and matter must be conserved inside stars

A

True

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23
Q

What does the formula E = mc^2 represent?

A

When 2 small nuclei fuse together, the new mass is just a fraction smaller that it should be. The missing mass is converted into energy, according to the formula E = mc^2 (c = speed of light)

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24
Q

How many constellation are recognized by the International Astronomical Union (IAU)?

A

88

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25
Q

Why does the IAU define a constellation by its boundaries, not its shape or patterns?

A

As more advanced telescopes and cameras capture images of the night sky, more and more stars fill the picture — so many that finding the shapes made by constellations becomes more difficult

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26
Q

How do astronomers indicate the location of newly discovered stars?

A

Astronomers indicate the location of newly discovered stars using the constellations boundary within which the6 are found. This is particularly helpful for variable stars, which fade and brighten instead of shining constantly

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27
Q

What is a variable star?

A

A star that fades and brightens instead of shinning constantly

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28
Q

Many of the constellations recognized by the IAU were named by who?

A

The Ancient Greeks, who learned about constellations from the ancient Babylonians, Assyrians, and Egyptians

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29
Q

True or False: All constellations we’re named in the past

A

False; some constellations were named and discovered in the modern era

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30
Q

What did the Greeks call constellations? What did it mean?

A

The Greeks called them “kataterismoi” meaning “placing of the gods”

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31
Q

What are the “old constellations”?

A

Of the 88 constellations recognized by the IAU, 48 have been known since the time of Claudius Ptolemy’s “Almagest”, a mathematical and astronomical treatise. these constellations are called “old constellations”

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32
Q

What are the Big Dipper, the Plough (which is apart of Ursa Major), and the Summer Triangle recognized as by the IAU?

A

Asterisms; not constellations

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33
Q

When were the 40 “new constellations” identified and named?

A

15th — 17th centuries

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34
Q

What are “new constellations” sometimes called?

A

Modern constellations

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35
Q

What did Amergio Vespucci do?

A

He mapped the night sky, as well as the land and oceans, as he explored the Southern Hemisphere

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36
Q

What is Amergio Vespucci credited for?

A

He is credited with identifying stars and constellations during the late 1400s, including Alpha and Beta Centauri (stars) and the Southern Cross (constellation)

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37
Q

What inspired Vespucci to study stars?

A

The ones in the Southern Hemisphere were nothing like the ones in his home, Italy

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38
Q

How will Northern Hemisphere constellations and asterisms appear from the Southern Hemisphere?

A

Upside down; and vice versa

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39
Q

How often do star patterns that are visible all year round in the North Pole appear in the South Pole?

A

Some star patterns that are visible all year in the Northern Hemisphere, because they circle the North Pole (circumpolar), only appear seasonally in the Southern Hemisphere. The Big Dipper asterism is an example

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40
Q

What did Nicolas-Louis de Lacaille do?

A

He was a French astronomer who catalogued 9,766 new southern stars in just 11 months, while stationed at the Cape of Good Hope in South Africa

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41
Q

True or False: Lacaille’s constellations are difficult to see without a telescope

A

True

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42
Q

How did Nicolas-Louis de Lacaille identify constellations?

A

He identified the constellations by inventing them. He chose stars to include in the constellations from regions of the sky where there had been relatively few.

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43
Q

Where did Lacaille’s inspiration for naming constellations come from?

A

It came from academic objects, such as a chemical furnace (Fornax Chemica), telescope (Telescopium), and microscope (microscopium)

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44
Q

How did Lacaille honor Cape Town and South Africa?

A

He named one of the constellations after Table Mountain (Mons Mensae), honoring Cape Town and South Africa, which he could see from his observatory

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45
Q

How are the IAU constellations given names?

A

The IAU constellations are given Latin names in two form. The nominative form, used to refer to the constellation itself, and the possessive form, used when the constellation name is included in the name of a star

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46
Q

What is sunlight sometimes called?

A

White light

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47
Q

What is the electromagnetic spectrum?

A

The range of all types of electromagnetic radiation, designated by wavelength

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48
Q

What is the range of wavelengths in visible light?

A

380 nm — 700 nm

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49
Q

How do the wavelengths of the colors that make up white light compare?

A

The different colors that make up white light have different wavelengths, all within the range of 380 nm to 700 nm, with violet having the shortest at 380 nm and the color red having the longest at 700 nm

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50
Q

What are source of visible light?

A

The sun, the stars, and light bulbs, such as florescent and LED bulbs

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51
Q

Visible Light Definition

A

Electromagnetic radiation with wavelengths between 380 nm and 700 nm

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52
Q

How is the electromagnetic spectrum arranged?

A

By wavelength, frequency, and energy

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53
Q

What happens as wavelengths get smaller along the electromagnetic spectrum?

A

The frequency and energy get higher

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54
Q

What happens as visible light, or white light, travels through a prism? What happens when the color spectrum travels through a prism?

A

As visible light oases through a prism, it separates into a spectrum of colors. As the spectrum of colors passes through a 2nd prism, the light emerges as white light

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55
Q

On the electromagnetic spectrum, which section has the lowest frequency?

A

Radio waves

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56
Q

What device captures radio waves?

A

A radio

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57
Q

What wavelengths do Night vision capture?

A

Infrared wave radiation

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58
Q

On the electromagnetic spectrum, what type of radiation as the highest frequency?

A

Gamma rays

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59
Q

What are the measures of frequency on the electromagnetic radiation spectrum from lowest to highest?

A

Radio wave, microwave, infrared radiation, visible light, ultraviolet radiation, x-rays, gamma rays

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60
Q

What is the range of wavelengths in ultraviolet light?

A

400 nm — 10nm

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61
Q

What is the natural source of ultraviolet light on Earth?

A

The sun

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62
Q

Non-visible light Definition

A

Electromagnetic radiation that cannot be seen by the unaided human eye

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63
Q

What is the range of wavelengths in radio waves?

A

1 mm — 100 km

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64
Q

What are radio waves used for?

A

To carry radio signals

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65
Q

What is the range of wavelengths in microwaves?

A

1mm — 100 m

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66
Q

How do microwaves warm up food?

A

Microwaves pass through food and cause the molecules of water in the food to vibrate. The food increases in temperature as the water molecules move faster

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67
Q

What is the range of wavelengths in x-rays?

A

0.01 nm — 10 nm

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68
Q

True or False: x-rays can pass through objects

A

True

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69
Q

How does an x-ray help us see bones?

A

X-rays pass through the human body. Bones absorb x-rays, which is why they appear white in an x-ray image. Tissues, organs, muscles, and fat do not absorb x-rays and will appear gray, or not show

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70
Q

How can studying the absorption and emission of light by elements in their gaseous form help us learn more about stars and other celestial objects?

A

Elements in their gaseous state absorb and emit wavelengths of light specific to each element. Scientists can capture the patterns of emission and absorption of light from stars and objects in space. They can analyze how the light wavelengths are separated, similar to how water droplets separate light into a rainbow. The data obtained this way provide information about the composition and other properties of celestial objects.

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71
Q

Wavelengths Definition

A

The distance from crest to crest of a wave pattern

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72
Q

What is spectroscopy?

A

The science of studying absorption and emission patterns, called spectra

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73
Q

How can spectra be represented?

A

As a visual line spectra, as a graph, and more

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74
Q

What does absorption spectra show?

A

Absorption spectra show a continuous spectrum with dark lines where wavelengths are absorbed by atoms

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75
Q

What medium of data is spectra information most useful in?

A

Spectra information is most useful when presented graphically. In a graph, peaks represent emission and the dips represent absorption for certain wavelengths. The magnitude of the peaks and dips indicate light intensity

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76
Q

What can measuring a wavelength at its highest point help astronomers calculate?

A

Measuring the wavelength at its highest point can help astronomers calculate the object’s temperature. A peak in the spectrum near the blue end of the scale indicates a hot, often young, star. A peak in the spectrum near the red end of the scale indicates a cooler star

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77
Q

What can certain peaks and dips in spectra indicate?

A

The presence of a certain element, this helps astronomers study the composition of different planets and stars. Each elements leaves its own mark on the spectrum

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78
Q

Since astronomers know where peaks and dips should appear on a spectra graph, what can they conclude when the lines shift?

A

Astronomers know where peaks and dips should appear. When those lines are shifted, it means that the object is in motion. This is known as the “Doppler Effect”. Shorter wavelengths mean the object is moving toward us. Longer wavelengths mean the object is moving away from us

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79
Q

What does the Big Bang theory describe?

A

It describes the beginning of the universe as an expanding universe starting with a gigantic explosion. As the universe cooled, hydrogen and helium atoms formed, which later condensed to form stars and galaxies

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80
Q

True or False: Spectroscopic evidence led to the development of the Big Bang theory

A

True

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81
Q

Frequency Definition

A

The number of waves that pass a point in a set amount of time

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82
Q

Through spectral analysis, what is the most abundant element in the universe?

A

Hydrogen

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83
Q

What have we learned by observing light emitted by hot glowing hydrogen from distant galaxies?

A

By observing light emitted by hot glowing hydrogen from distant galaxies, scientists noticed that spectral lines for hydrogen shifted to lower frequency, the higher wavelength red end of the visible spectrum. This Doppler Effect shift indicates that the viewer is moving away from the source, which is the distant galaxy. In fact all galaxies are moving away from us and others.

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84
Q

What makes images of galaxies, such as Andromeda, possible?

A

Hydrogen

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85
Q

True or False: The faster from the origin a galaxy is, the faster it moves and the faster the galaxies move away from each other

A

True

86
Q

True or False: How long ago the Big Bang occurred is based on the rate of expansion and the distances between galaxies

A

True

87
Q

What determines a star’s color?

A

Surface temperature

88
Q

Apparent Magnitude Definition

A

How bright a star appears from Earth

89
Q

True or False: Apparent Magnitude is independent of the star’s distance or characteristics

A

True

90
Q

To deal with the flaws of Apparent Magnitude, what did astronomers develop?

A

To deal with the flaws of Apparent Magnitude, astronomers developed absolute magnitude. This value is the brightness a star would have at a distance of 10 parsecs or 32.6 light years away from the viewer.

91
Q

True or False: Absolute Magnitude expresses how bright the star actually is

A

True

92
Q

Absolute Magnitude Definition

A

How bright a star appears at a set distance

93
Q

What happens as the distance of light traveling from a star doubles?

A

The apparent brightness goes down by a factor of 4

94
Q

Does all mater emit electromagnetic radiation?

A

Yes

95
Q

Electromagnetic Radiation Definition

A

Waves of energy emitted by matter

96
Q

What can scientists determine from analyzing the spectral signature, or energy emitted by a star?

A

Chemical composition and surface temperature

97
Q

Spectroscopy Definition

A

Study of spectra produced by matter emitting radiation

98
Q

Spectral Lines Definition

A

Pattern of dark lines and colors representing emitted energy

99
Q

How do astronomers classify stars?

A

By their spectral class

100
Q

What is the spectral class of a star dependent on?

A

Its color and temperature

101
Q

What spectral class are the coolest stars in? What spectral class are the hottest stars in?

A

The coolest stars are red (Class M) and orange (Class K), while the hottest stars are blue (Class O and Class B)

102
Q

What is each spectral class subdivided into?

A

Each spectral class is them subdivided, from 0 to 9, with higher numbers meaning the sun is cool. The higher the number the cooler the star

103
Q

How is the sun classified using spectral class?

A

The sun is a Class G yellow star, composed primarily of hydrogen and helium

104
Q

What is the order of Spectral Class and Color from coolest to hottest?

A

Class M (red), Class K (orange), Class G (Yellow Variant), Class F (Yellow), Class A (White), Class B (Light Blue), Class O (Dark Blue)

105
Q

Who created the Hertzsprung-Russell Diagram and how?

A

In the early 1900s, Danish astronomer Ejnar Hertzsprung and American astronomer Henry Norris Russell independently came up with a diagram that shows the relationship between properties of stars, such as color, temperature, and luminosity or brightness. It is called the Hertzsprung-Russell Diagram, and it is useful in studying the properties of stars.

106
Q

How is luminosity and temperature organized on the H-R Diagram?

A

On the H-R diagram, luminosity is plotted on the y-axis, with brightest stars at the top. Temperature (Kelvin Scale) is plotted on the x-axis, with hottest stars on the left

107
Q

What are the four main categories of stars?

A

Main sequence, Supergiants, Giants, and white dwarfs

108
Q

What are Main Sequence stars?

A

Main sequence stars, such as our sun, are the most common. They are stable stars using hydrogen in fusion reactions to create energy

109
Q

What are Supergiants?

A

Supergiants are cool stars that have high luminosity because they are large. Main sequence stars that use up their hydrogen fuel can become giants or supergiants

110
Q

What are Giants?

A

Giants are smaller than Supergiants but hotter, giving them only slightly less luminosity than supergiants

111
Q

What are White Dwarfs?

A

White Dwarfs are hot but have low luminosity because they are small. These are the dense cores of old stars that have thrown off their outer layers

112
Q

How is the size is a star described?

A

The size of a star is described by comparing it to the sun’s radius. A star with one solar radius is the same size of the sun. A star measuring five solar radii is 5x the size of the sun

113
Q

True or False: Size + surface temperature = luminosity

A

True

114
Q

How is the mass of a star described?

A

The mass of a star is described by comparing it to the mass of the sun. So if a star has a mass of one it would have the same mass of the sun. Stars can also have different densities. Two stars can be the same size but have different masses

115
Q

On what scale is a star’s surface temperature measured on?

A

It is measured on the Kelvin scale. Hot stars can be around 50,000 Kelvin (K), or about 89,500 degrees Fahrenheit. Cool stars can be around 2,500 K (4,040 degrees Fahrenheit). The sun is about 5,500 K (9,440 degrees Fahrenheit)

116
Q

What color are average temperature stars?

A

White or yellow

117
Q

True or False: stars can be a blend of colors

A

True

118
Q

What is a star’s brightness described by?

A

It is described by its luminosity and magnitude

119
Q

What is Luminosity?

A

The actual amount of light a star radiates

120
Q

What are the properties of stars?

A

Size, mass, temperature, color, brightness

121
Q

True or False: All objects in the universe emit, absorb, and reflect electromagnetic radiation in different ways

A

True

122
Q

What do astronomers use a spectrograph for?

A

To break up the electromagnetic radiation into component colors

123
Q

True or False: Stars have light spectra

A

True

124
Q

Spectrograph Definition

A

A tool that astronomers can use to see the light spectrum of a star

125
Q

Light Spectrum Definition

A

The colors of light that are coming from a star

126
Q

What does the light spectrum enable astronomers to do?

A

The light spectrum of a star allows astronomers to learn about what a star is composed of, it’s temperature, and it’s density. Astronomers can also estimate the mass and size of a star from its light spectrum

127
Q

True or False: One the H-R diagram, Hertzsprung and Russell plotted stars they observed and they discovered that they could relate the size, color, and other properties of stars on the diagram

A

True

128
Q

Where is absolute magnitude located on the H-R Diagram?

A

On the right vertical axis

129
Q

True or False: Astronomers study bot absolute and apparent magnitudes

A

True

130
Q

Where is the luminosity scale dimmest and highest on the H-R Diagram?

A

It is dimmest at the bottom and brighter at the top. The lower you go on the scale the dimmer the star

131
Q

What does each dot on the H-R diagram represent?

A

Each dot on the H-R diagram represents a star whose absolute magnitude and spectral class is known

132
Q

What is the luminosity of the sun as labeled on the H-R diagram?

A

1

133
Q

The warmth and light are two types of energy released by the sun during what?

A

Nuclear fusion reactions

134
Q

What happens in nuclear fusion reactions?

A

In Nuclear fusion reactions, two atoms collide and are fused together to make a new atom. Nuclear fusion reactions also release a large amount of energy, some of which can be transformed into light and heat

135
Q

Nuclear Fusion Definition

A

A reaction that makes a new atom from other atoms

136
Q

How many neutrons, protons, and electrons does Hydrogen have?

A

Hydrogen, as the smallest and simplest atom on the periodic table, has one proton, sometimes a neutron, and one electron

137
Q

How many neutrons, electrons, and protons does Helium have?

A

Helium contains two protons, two neutrons, and two electrons

138
Q

What happens as you move through the periodic table?

A

Moving through the periodic table, they atoms get larger and become higher in mass because they are made up of more neutrons, protons, and electrons

139
Q

What do scientists call the first three elements on the periodic table?

A

Scientists call the first three elements of the periodic table, which are the smallest, the light elements. These elements — hydrogen, helium, and lithium — have one, two, and three protons in their nucleus respectively

140
Q

Light Element Definition

A

An atom with one, two, or three protons in its nucleus

141
Q

When do scientists believe the light elements were formed?

A

They believe the light elements formed in about the first 3 minutes after the Big Bang

142
Q

What happened in the earliest stages of the Big Bang?

A

In the earliest stages of the Big Bang, matter consisted of protons, neutrons, and electrons in an intensely hot and rapidly expanded region. It was under these conditions that the atomic particles formed the light elements. At this stage, the universe was composed of 75% hydrogen, about 25% helium, and less than 1% lithium

143
Q

What is matter in the form of protons and neutrons held together in the nucleus by?

A

Matter in the form of protons and neutrons is held together in the nucleus by forces. When atoms fuse together in nuclear fusion to form larger elements, some of the energy in those forces is released

144
Q

What happened as the early universe expanded after the Big Bang?

A

As the early universe expanded after the Big Bang, clouds of light elements condensed into dense bodies. Due to high pressure and temperature, hydrogen started undergoing nuclear fusion, and stars were born

145
Q

What are the Heavy Elements?

A

In all but the smallest stars, additional nuclear fusion reactions took place, forming atoms with even more protons in their nuclei. In larger stars, the fusion reactions continued until iron was produced. These elements produced in stars by nuclear fusion are called the heavy elements

146
Q

Heavy Element Definition

A

An atom with four or more protons, up to the number of atoms in iron

147
Q

What is the range of Heavy Elements?

A

Beryllium (Be) — Iron (Fe)

148
Q

What do all stars continue doing throughout most of their lifecycle?

A

All stars, including those that produce heavy elements, continue to produce helium atoms from hydrogen atoms during most of their lifecycle

149
Q

What is the process to produce helium from hydrogen used by larger stars — stars about the same size of the sun or larger — called?

A

The CNO cycle

150
Q

What does the CNO cycle stand for?

A

The CNO Cycle stands for carbon, nitrogen, and oxygen atoms that are involved in the series of nuclear reactions

151
Q

How does the CNO cycle progress?

A

The CNO cycle starts with a hydrogen atom fusing with a carbon atom and ends with a helium atom and the regeneration of the carbon atom. Energy is also released in the form of gamma rays (y) and neutrinos (v)

152
Q

What do nuclear fusion reactions needed to make elements heavier than iron require?

A

They require more energy to start that stars have

153
Q

Where are elements heavier than iron made?

A

Elements heavier than iron are made in large to very large stars. Their mass creates more pressure and higher temperatures in the interior, making it easier for nuclear fusion reactions to take place

154
Q

What happens near the end of a large stars lifecycle, that has to do with elements?

A

Toward the end of a star life cycle, when the hydrogen fuel has been used up, the star collapses in on itself and explodes with tremendous energy. The explosion has enough energy for some of the elements in the star to fuse together to make even heavier elements. This process makes elements that are as heavy as uranium. The stars explosion, or supernova, then scatters the elements across space to form the dust that can condense into new planets and stars

155
Q

What is the range of the heavier elements?

A

The heavier elements span from cobalt (27) to uranium (92)

156
Q

After the heavier elements, where are the rest of the elements made.

A

They are made in lavatories by scientists, and are unstable and exist briefly before breaking down into other, smaller atoms. Additionally, scientists are not sure if stars can produce these elements.

157
Q

What is the lifecycle of a star like from a nebula to a main sequence star?

A

All stars are born in a nebula — a giant cloud of gas an dust. Eventually, gravity pulls the cloud’s hydrogen together and the condensed gas starts to spin. The faster the gas spins, the hotter it becomes until a protostar forms. When the temperature of the protostar reaches 15,000,000 degrees Celsius, it triggers nuclear fusion in its core. By converting hydrogen into helium, the protostar achieves the next stage in its life cycle — becoming a stable, brightly glowing main sequence star. Stars remain in this form , radiating their light and heat into space, for millions to billions of years.

158
Q

Protostar Definition

A

A structure that forms as hydrogen in a nebula spins faster and the temperature increases

159
Q

What determines how a star’s lifecycle will end?

A

The mass of a protostar

160
Q

What is the lifecycle of an average-sized star after the main sequence?

A

When an average-sized star, such as our sun, has used up its hydrogen fuel, it becomes a red giant. The core contracts and the outer shell starts to expand, glowing red as it cools. The star then burns helium for another billion years until the helium fuses into carbon. The core collapses again, expelling the star’s outer layers, which form a planetary nebula. The core itself remains as a white dwarf star. Astronomers speculate that in time the white dwarf will cool until it becomes a black dwarf, which no longer emits significant light or heat

161
Q

Red Giant Definition

A

Structure that forms when stars run out of hydrogen and their outer layers expand and cool

162
Q

Planetary Nebula Definition

A

Structure that forms when the carbon core of an average size star collapses, expelling the outer layers

163
Q

White Dwarf Definition

A

Structure that forms as the remaining core of a red giant

164
Q

How does a star’s mass correlate with its lifespan?

A

The larger a star’s mass, the shorter it’s life cycle. The matter in its nebula determines its mass

165
Q

What are nebulas that create stars called?

A

Not all nebula produce stars. The ones that do are called stellar nebula

166
Q

True or False: Gravity “smashes” hydrogen atoms into helium atoms

A

True

167
Q

What happens as hydrogen in stars begin to run out?

A

When hydrogen begins to run out, the star starts losing the ability to produce heat. The core then becomes unstable and contracts (shrinks) and the outer shell expands. The star then cools and grows red, into a red giant (larger than main sequence star)

168
Q

What happens in the core of a red giant?

A

Helium fuses into carbon

169
Q

What happens after the red giant stage in high mass stars?

A

In high mass stars, the red giant turns into a red supergiant. Then they collapse, undergoing a supernova explosion. This is like a shockwave, blowing the outer layers of the stars, and scattering stellar material. If the core is about 1.4 to 3 times as massive as our sun, it condenses, forming a tiny, dense neutron star. If the core is more than 3 times the mass of the sun, it collapses on its self, forming a black hole.

170
Q

How big are massive stars compared to the sun?

A

Massive stars are 10 times or more the size of the sun

171
Q

What happens when a massive star runs out of hydrogen fuel?

A

It’s outer shell expands into an enormous auger red giant. Nuclear fusion in the core continues until it eventually creates an iron core. At this point, all fusion stops. The core rapidly contracts and then a massive explosion called a supernova occurs. The resulting shockwave sends a cloud of heavy elements hurtling into space. The remaining core of the exploded star continues to collapse

172
Q

Supernova Definition

A

Explosion in which a super red giant expels heavy elements into space

173
Q

What is the size of neutron stars? How dense can they be?

A

A neutron star can be only a few km across, but it’s matter is so dense that a teaspoon can weigh a billion tons

174
Q

Neutron Star Definition

A

Structure that forms when the mass of the remaining core after a supernova is between 1.4 and 3.0 times the mass of the sun

175
Q

Black Hole Definition

A

Object that forms with a gravity so strong that not even light can escape

176
Q

What explains why stars shine so brightly?

A

The nuclear reactions that occur in the cores of stars provide enough energy for stars to shine brightly for millions or billions of years

177
Q

What happens during a supernova?

A

In a supernova, a star’s core shrinks and reaches temperatures of 100 billion degrees, triggering the explosion just in a few seconds

178
Q

What is the life cycle of an average star?

A

Nebula, protostar, main sequence star, red giant, planetary nebula, white dwarf, black dwarf

179
Q

What is the largest explosion in space?

A

Supernovas

180
Q

True or False: What scientists understand about supernovas and stellar evolution is a mixture of what they have observed and theories they have developed

A

True

181
Q

What are binary star systems?

A

85% of the stars in the Milky Way are part of multiple star systems . Systems with 2 stars revolving around each other are called binary star systems

182
Q

How are astronomers able to determine the mass of stars in binary systems?

A

By studying their orbits

183
Q

What do Stellar Diagrams provide?

A

Stellar Diagrams give information about the stellar evolution of average stars and massive stars

184
Q

Why is stellar evolution inevitable?

A

Because stars burn, and to burn, they need fuel

185
Q

How long did the sun spend in the protostar phase?

A

The sun spent 10,000,000 years in its protostar phase before nuclear reactions in its core signaled the sun’s birth as an averaged-sized star

186
Q

How long has the sun been in its mature, main sequence phase?

A

The sun is about 4.5 billion years into its mature phase, and it has another 5.5 billion years to go

187
Q

What will happen as the sun moves out of the main sequence?

A

Eventually, the sun will be 3x larger that it is now, which would make Earth 100 Kelvin hotter

188
Q

How many Earths could fit inside the sun?

A

1.3 million

189
Q

What is the diameter of the sun?

A

864,000 miles (or 109 Earths)

190
Q

What is the surface temperature of the sun? What is the temperature of its core?

A

The sun has a surface temperature of 10,000 degrees Fahrenheit and its core is 27 million degrees Fahrenheit (ST of 9,932 degrees Fahrenheit to be specific)

191
Q

What is Betelgeuse?

A

A red supergiant near the end of it life cycle. It is one of the largest known stars

192
Q

How does Betelgeuse’s diameter compare to the sun’s?Its brightness

A

Betelgeuse has a diameter 500 times the size of the sun’s, and is one of the brightest stars in the Orion constellation

193
Q

What is the surface temperature of Betelgeuse?

A

Betelgeuse has a low surface temperature of about 6,000 degrees Fahrenheit

194
Q

How does the amount of energy Betelgeuse emits compare to the sun’s?

A

Betelgeuse emits about 7,500 times as much energy as the sun

195
Q

How does Rigel compare to the sun?

A

Rigel is also in the Orion constellation, and is 47,000 times brighter than the sun and 70 times larger. Rigel has a luminosity of 100,000 times that of the sun, and emits radiation 66,000 times more powerful than the sun’s

196
Q

How does Aldebaran compare to the sun?

A

Aldebaran is an orange red giant about 44x the size of the sun and 150x brighter

197
Q

How does Sirius A compare to the sun?

A

Sirius A is about two times the size of the sun, and is the brightest star in the sky. It is a main sequence star, like our sun, but hotter. It is 300 million out of 1 billion years of its main sequence life cycle and the sun is 4 billion out of 14 billion

198
Q

What is the brightest star in the Milky Way?

A

The Pistol Star, which is 2 million times brighter than the sun and 100 time larger

199
Q

What enables the sun to generate massive amounts of energy?

A

Its composition

200
Q

What is luminosity measured in?

A

Luminosity is the amount of energy generated by a star, as measured in watts per second

201
Q

True or False: the bigger the star, the more nuclei are available to fuse, and the more energy is produced

A

True

202
Q

What percentage of stars are in the main sequence?

A

90%

203
Q

Only for what type of star is there a relationship between surface temperature and luminosity?

A

Main sequence stars

204
Q

Red Supergiant Definition

A

A massive star appearing yellow or red and in th process of dying

205
Q

How does a white dwarf compare to the sun?

A

A typical white dwarf may be only 1/2 as large as the sun, but it reaches temperatures 10 times higher

206
Q

How does the luminosity of white dwarfs compare to that of the sun’s?

A

The luminosity of white dwarfs is 10 to 100 times lower than the sun’s

207
Q

True or False: Metrics are ways of measuring natural phenomena

A

True

208
Q

True or False: magnetic field strength is a characteristic of stars

A

True

209
Q

What is emission spectrum?

A

The spectrum of frequencies of electromagnetic radiation emitted by an element during its transition from a high energy state to a low energy state

210
Q

What causes different patterns of spectral lines to appear in different elements?

A

The atoms of each element have a unique number of electrons within the surrounding energy levels. This means that each atom type will produce a unique pattern of colored lines in spectra generated by spectroscopy

Connexus 8: Science (8 decks)

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