Astronomy: The Stars (Unit 1) Flashcards
1
Q
Constellation Definition
A
A group of stars forming a recognizable pattern
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
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
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
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
6
Q
What are the characteristics of a star?
A
Temperature, size, color, brightness, and composition
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
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
9
Q
How do we classify specific constellations?
A
Based on what they remind us of
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
11
Q
What does the Big Dipper look like?
A
A big spoon or ladle
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
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
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
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
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
17
Q
Plasma Definition
A
A state of matter in which electrons separate from atomic nuclei, but remain balanced in number
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)
19
Q
What do astronomers often compare stars to?
A
The sun; for example, the masses of other stars are given in solar masses
20
Q
What is the solar mass of Alpha Centauri?
A
1.08 solar masses
21
Q
What is the solar mass of Betelgeuse?
A
Betelgeuse, one of the brightest stars in the sky, is about 20 solar masses
22
Q
True or False: Energy and matter must be conserved inside stars
A
True
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)
24
Q
How many constellation are recognized by the International Astronomical Union (IAU)?
A
88
25
Why does the IAU define a constellation by its boundaries, not its shape or patterns?
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
26
How do astronomers indicate the location of newly discovered stars?
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
27
What is a variable star?
A star that fades and brightens instead of shinning constantly
28
Many of the constellations recognized by the IAU were named by who?
The Ancient Greeks, who learned about constellations from the ancient Babylonians, Assyrians, and Egyptians
29
True or False: All constellations we’re named in the past
False; some constellations were named and discovered in the modern era
30
What did the Greeks call constellations? What did it mean?
The Greeks called them “kataterismoi” meaning “placing of the gods”
31
What are the “old constellations”?
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”
32
What are the Big Dipper, the Plough (which is apart of Ursa Major), and the Summer Triangle recognized as by the IAU?
Asterisms; not constellations
33
When were the 40 “new constellations” identified and named?
15th — 17th centuries
34
What are “new constellations” sometimes called?
Modern constellations
35
What did Amergio Vespucci do?
He mapped the night sky, as well as the land and oceans, as he explored the Southern Hemisphere
36
What is Amergio Vespucci credited for?
He is credited with identifying stars and constellations during the late 1400s, including Alpha and Beta Centauri (stars) and the Southern Cross (constellation)
37
What inspired Vespucci to study stars?
The ones in the Southern Hemisphere were nothing like the ones in his home, Italy
38
How will Northern Hemisphere constellations and asterisms appear from the Southern Hemisphere?
Upside down; and vice versa
39
How often do star patterns that are visible all year round in the North Pole appear in the South Pole?
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
40
What did Nicolas-Louis de Lacaille do?
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
41
True or False: Lacaille’s constellations are difficult to see without a telescope
True
42
How did Nicolas-Louis de Lacaille identify constellations?
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.
43
Where did Lacaille’s inspiration for naming constellations come from?
It came from academic objects, such as a chemical furnace (Fornax Chemica), telescope (Telescopium), and microscope (microscopium)
44
How did Lacaille honor Cape Town and South Africa?
He named one of the constellations after Table Mountain (Mons Mensae), honoring Cape Town and South Africa, which he could see from his observatory
45
How are the IAU constellations given names?
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
46
What is sunlight sometimes called?
White light
47
What is the electromagnetic spectrum?
The range of all types of electromagnetic radiation, designated by wavelength
48
What is the range of wavelengths in visible light?
380 nm — 700 nm
49
How do the wavelengths of the colors that make up white light compare?
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
50
What are source of visible light?
The sun, the stars, and light bulbs, such as florescent and LED bulbs
51
Visible Light Definition
Electromagnetic radiation with wavelengths between 380 nm and 700 nm
52
How is the electromagnetic spectrum arranged?
By wavelength, frequency, and energy
53
What happens as wavelengths get smaller along the electromagnetic spectrum?
The frequency and energy get higher
54
What happens as visible light, or white light, travels through a prism? What happens when the color spectrum travels through a prism?
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
55
On the electromagnetic spectrum, which section has the lowest frequency?
Radio waves
56
What device captures radio waves?
A radio
57
What wavelengths do Night vision capture?
Infrared wave radiation
58
On the electromagnetic spectrum, what type of radiation as the highest frequency?
Gamma rays
59
What are the measures of frequency on the electromagnetic radiation spectrum from lowest to highest?
Radio wave, microwave, infrared radiation, visible light, ultraviolet radiation, x-rays, gamma rays
60
What is the range of wavelengths in ultraviolet light?
400 nm — 10nm
61
What is the natural source of ultraviolet light on Earth?
The sun
62
Non-visible light Definition
Electromagnetic radiation that cannot be seen by the unaided human eye
63
What is the range of wavelengths in radio waves?
1 mm — 100 km
64
What are radio waves used for?
To carry radio signals
65
What is the range of wavelengths in microwaves?
1mm — 100 m
66
How do microwaves warm up food?
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
67
What is the range of wavelengths in x-rays?
0.01 nm — 10 nm
68
True or False: x-rays can pass through objects
True
69
How does an x-ray help us see bones?
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
70
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?
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.
71
Wavelengths Definition
The distance from crest to crest of a wave pattern
72
What is spectroscopy?
The science of studying absorption and emission patterns, called spectra
73
How can spectra be represented?
As a visual line spectra, as a graph, and more
74
What does absorption spectra show?
Absorption spectra show a continuous spectrum with dark lines where wavelengths are absorbed by atoms
75
What medium of data is spectra information most useful in?
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
76
What can measuring a wavelength at its highest point help astronomers calculate?
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
77
What can certain peaks and dips in spectra indicate?
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
78
Since astronomers know where peaks and dips should appear on a spectra graph, what can they conclude when the lines shift?
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
79
What does the Big Bang theory describe?
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
80
True or False: Spectroscopic evidence led to the development of the Big Bang theory
True
81
Frequency Definition
The number of waves that pass a point in a set amount of time
82
Through spectral analysis, what is the most abundant element in the universe?
Hydrogen
83
What have we learned by observing light emitted by hot glowing hydrogen from distant galaxies?
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.
84
What makes images of galaxies, such as Andromeda, possible?
Hydrogen
85
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
True
86
True or False: How long ago the Big Bang occurred is based on the rate of expansion and the distances between galaxies
True
87
What determines a star’s color?
Surface temperature
88
Apparent Magnitude Definition
How bright a star appears from Earth
89
True or False: Apparent Magnitude is independent of the star’s distance or characteristics
True
90
To deal with the flaws of Apparent Magnitude, what did astronomers develop?
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
True or False: Absolute Magnitude expresses how bright the star actually is
True
92
Absolute Magnitude Definition
How bright a star appears at a set distance
93
What happens as the distance of light traveling from a star doubles?
The apparent brightness goes down by a factor of 4
94
Does all mater emit electromagnetic radiation?
Yes
95
Electromagnetic Radiation Definition
Waves of energy emitted by matter
96
What can scientists determine from analyzing the spectral signature, or energy emitted by a star?
Chemical composition and surface temperature
97
Spectroscopy Definition
Study of spectra produced by matter emitting radiation
98
Spectral Lines Definition
Pattern of dark lines and colors representing emitted energy
99
How do astronomers classify stars?
By their spectral class
100
What is the spectral class of a star dependent on?
Its color and temperature
101
What spectral class are the coolest stars in? What spectral class are the hottest stars in?
The coolest stars are red (Class M) and orange (Class K), while the hottest stars are blue (Class O and Class B)
102
What is each spectral class subdivided into?
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
How is the sun classified using spectral class?
The sun is a Class G yellow star, composed primarily of hydrogen and helium
104
What is the order of Spectral Class and Color from coolest to hottest?
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
Who created the Hertzsprung-Russell Diagram and how?
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
How is luminosity and temperature organized on the H-R Diagram?
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
What are the four main categories of stars?
Main sequence, Supergiants, Giants, and white dwarfs
108
What are Main Sequence stars?
Main sequence stars, such as our sun, are the most common. They are stable stars using hydrogen in fusion reactions to create energy
109
What are Supergiants?
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
What are Giants?
Giants are smaller than Supergiants but hotter, giving them only slightly less luminosity than supergiants
111
What are White Dwarfs?
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
How is the size is a star described?
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
True or False: Size + surface temperature = luminosity
True
114
How is the mass of a star described?
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
On what scale is a star’s surface temperature measured on?
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
What color are average temperature stars?
White or yellow
117
True or False: stars can be a blend of colors
True
118
What is a star’s brightness described by?
It is described by its luminosity and magnitude
119
What is Luminosity?
The actual amount of light a star radiates
120
What are the properties of stars?
Size, mass, temperature, color, brightness
121
True or False: All objects in the universe emit, absorb, and reflect electromagnetic radiation in different ways
True
122
What do astronomers use a spectrograph for?
To break up the electromagnetic radiation into component colors
123
True or False: Stars have light spectra
True
124
Spectrograph Definition
A tool that astronomers can use to see the light spectrum of a star
125
Light Spectrum Definition
The colors of light that are coming from a star
126
What does the light spectrum enable astronomers to do?
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
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
True
128
Where is absolute magnitude located on the H-R Diagram?
On the right vertical axis
129
True or False: Astronomers study bot absolute and apparent magnitudes
True
130
Where is the luminosity scale dimmest and highest on the H-R Diagram?
It is dimmest at the bottom and brighter at the top. The lower you go on the scale the dimmer the star
131
What does each dot on the H-R diagram represent?
Each dot on the H-R diagram represents a star whose absolute magnitude and spectral class is known
132
What is the luminosity of the sun as labeled on the H-R diagram?
1
133
The warmth and light are two types of energy released by the sun during what?
Nuclear fusion reactions
134
What happens in nuclear fusion reactions?
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
Nuclear Fusion Definition
A reaction that makes a new atom from other atoms
136
How many neutrons, protons, and electrons does Hydrogen have?
Hydrogen, as the smallest and simplest atom on the periodic table, has one proton, sometimes a neutron, and one electron
137
How many neutrons, electrons, and protons does Helium have?
Helium contains two protons, two neutrons, and two electrons
138
What happens as you move through the periodic table?
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
What do scientists call the first three elements on the periodic table?
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
Light Element Definition
An atom with one, two, or three protons in its nucleus
141
When do scientists believe the light elements were formed?
They believe the light elements formed in about the first 3 minutes after the Big Bang
142
What happened in the earliest stages of the Big Bang?
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
What is matter in the form of protons and neutrons held together in the nucleus by?
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
What happened as the early universe expanded after the Big Bang?
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
What are the Heavy Elements?
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
Heavy Element Definition
An atom with four or more protons, up to the number of atoms in iron
147
What is the range of Heavy Elements?
Beryllium (Be) — Iron (Fe)
148
What do all stars continue doing throughout most of their lifecycle?
All stars, including those that produce heavy elements, continue to produce helium atoms from hydrogen atoms during most of their lifecycle
149
What is the process to produce helium from hydrogen used by larger stars — stars about the same size of the sun or larger — called?
The CNO cycle
150
What does the CNO cycle stand for?
The CNO Cycle stands for carbon, nitrogen, and oxygen atoms that are involved in the series of nuclear reactions
151
How does the CNO cycle progress?
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
What do nuclear fusion reactions needed to make elements heavier than iron require?
They require more energy to start that stars have
153
Where are elements heavier than iron made?
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
What happens near the end of a large stars lifecycle, that has to do with elements?
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
What is the range of the heavier elements?
The heavier elements span from cobalt (27) to uranium (92)
156
After the heavier elements, where are the rest of the elements made.
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
What is the lifecycle of a star like from a nebula to a main sequence star?
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
Protostar Definition
A structure that forms as hydrogen in a nebula spins faster and the temperature increases
159
What determines how a star’s lifecycle will end?
The mass of a protostar
160
What is the lifecycle of an average-sized star after the main sequence?
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
Red Giant Definition
Structure that forms when stars run out of hydrogen and their outer layers expand and cool
162
Planetary Nebula Definition
Structure that forms when the carbon core of an average size star collapses, expelling the outer layers
163
White Dwarf Definition
Structure that forms as the remaining core of a red giant
164
How does a star’s mass correlate with its lifespan?
The larger a star’s mass, the shorter it’s life cycle. The matter in its nebula determines its mass
165
What are nebulas that create stars called?
Not all nebula produce stars. The ones that do are called stellar nebula
166
True or False: Gravity “smashes” hydrogen atoms into helium atoms
True
167
What happens as hydrogen in stars begin to run out?
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
What happens in the core of a red giant?
Helium fuses into carbon
169
What happens after the red giant stage in high mass stars?
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
How big are massive stars compared to the sun?
Massive stars are 10 times or more the size of the sun
171
What happens when a massive star runs out of hydrogen fuel?
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
Supernova Definition
Explosion in which a super red giant expels heavy elements into space
173
What is the size of neutron stars? How dense can they be?
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
Neutron Star Definition
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
Black Hole Definition
Object that forms with a gravity so strong that not even light can escape
176
What explains why stars shine so brightly?
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
What happens during a supernova?
In a supernova, a star’s core shrinks and reaches temperatures of 100 billion degrees, triggering the explosion just in a few seconds
178
What is the life cycle of an average star?
Nebula, protostar, main sequence star, red giant, planetary nebula, white dwarf, black dwarf
179
What is the largest explosion in space?
Supernovas
180
True or False: What scientists understand about supernovas and stellar evolution is a mixture of what they have observed and theories they have developed
True
181
What are binary star systems?
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
How are astronomers able to determine the mass of stars in binary systems?
By studying their orbits
183
What do Stellar Diagrams provide?
Stellar Diagrams give information about the stellar evolution of average stars and massive stars
184
Why is stellar evolution inevitable?
Because stars burn, and to burn, they need fuel
185
How long did the sun spend in the protostar phase?
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
How long has the sun been in its mature, main sequence phase?
The sun is about 4.5 billion years into its mature phase, and it has another 5.5 billion years to go
187
What will happen as the sun moves out of the main sequence?
Eventually, the sun will be 3x larger that it is now, which would make Earth 100 Kelvin hotter
188
How many Earths could fit inside the sun?
1.3 million
189
What is the diameter of the sun?
864,000 miles (or 109 Earths)
190
What is the surface temperature of the sun? What is the temperature of its core?
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
What is Betelgeuse?
A red supergiant near the end of it life cycle. It is one of the largest known stars
192
How does Betelgeuse’s diameter compare to the sun’s?Its brightness
Betelgeuse has a diameter 500 times the size of the sun’s, and is one of the brightest stars in the Orion constellation
193
What is the surface temperature of Betelgeuse?
Betelgeuse has a low surface temperature of about 6,000 degrees Fahrenheit
194
How does the amount of energy Betelgeuse emits compare to the sun’s?
Betelgeuse emits about 7,500 times as much energy as the sun
195
How does Rigel compare to the sun?
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
How does Aldebaran compare to the sun?
Aldebaran is an orange red giant about 44x the size of the sun and 150x brighter
197
How does Sirius A compare to the sun?
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
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What is the brightest star in the Milky Way?
The Pistol Star, which is 2 million times brighter than the sun and 100 time larger
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What enables the sun to generate massive amounts of energy?
Its composition
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What is luminosity measured in?
Luminosity is the amount of energy generated by a star, as measured in watts per second
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True or False: the bigger the star, the more nuclei are available to fuse, and the more energy is produced
True
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What percentage of stars are in the main sequence?
90%
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Only for what type of star is there a relationship between surface temperature and luminosity?
Main sequence stars
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Red Supergiant Definition
A massive star appearing yellow or red and in th process of dying
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How does a white dwarf compare to the sun?
A typical white dwarf may be only 1/2 as large as the sun, but it reaches temperatures 10 times higher
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How does the luminosity of white dwarfs compare to that of the sun’s?
The luminosity of white dwarfs is 10 to 100 times lower than the sun’s
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True or False: Metrics are ways of measuring natural phenomena
True
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True or False: magnetic field strength is a characteristic of stars
True
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What is emission spectrum?
The spectrum of frequencies of electromagnetic radiation emitted by an element during its transition from a high energy state to a low energy state
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What causes different patterns of spectral lines to appear in different elements?
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
