Unit 5 Flashcards
the sun makes up what percent of mass in the solar system
99.86
thermonuclear fusion
Arthur Eddington thought that temp at suns core was hot enough for 4 hydrogen atoms to make a helium atom
energy in thermonuclear fusion
some mass is lost and converted to energy
luminosity
suns total energy output 3.9*10^26 watts
hydrogen burning
hydrogen converted to helium
hydrostatic equilibrium
sun can support its own weight
thermal equilibrium
sun put out constant amount of energy
temperature
average motion of atoms or molecules
heat
energy that flows
conduction
heat transfer through touch
convection
flow, liquids and gases
radiation
heat transferred through space
Electromagnetic radiation
energy from sun to earth (no medium)
Einstein’s theory of special relativity implied which of the following?
Energy and matter are interchangeable.
magnitude scale
describes how bright an object appears
apparent magnitude
how bright the object appears to observer
absolute magnitude
measured by energy output of star
inverse square law
apparent brightness is inversely proportional to the square of distance between observer and source
Star A is a first magnitude star. Star B is a sixth magnitude star. Which star is brighter and by how much
Star A is 100 times brighter than star B.
Which of the following best describes the relationship between absolute magnitude?
Absolute magnitude is the apparent magnitude an object would have at a distance of ten parsecs.
How many magnitude 3 stars does it take to get as much light as one magnitude 2 star?
2.5
parallax
apparent shifting of position of an object because of a change in point of view
d=1/p distance equals one over parallax angle
1/5/8=8/5
In the parallax equation D = 1/p, which of the following units is used to measure the distance?
parsecs
If a star is 11/6 parsecs away, what is its parallax angle (in fraction notation) in arc seconds?
6/11
protoplanet hypothesis
solar system started as a nebula that condensed and formed the sun
nebula
cloud of dust and gas
accretion
accumulation of material using gravity
protostars
high mass: blue stars
low mass: yellow stars
dies
stars die when there is no more fuel to produce heat
low mass
star collapses and eventually becomes a brown dwarf
high mass
contracts and then a supernova creates an explosion, the central core stays and becomes a neutron star
pulsars
radio pulses from objects in universe
burster
matter collects on neutron star, then bursts
nova
visible flash from white dwarf binaries
The central core that remains after a supernova is known as which of the following?
A neutron star
spectrum
specific frequencies of electromagnetic radiation it gives off, gives a clue to the temp of the star
visible color
blue stars are hotter than red stars
spectral classification
O, B, A, F, G, K, M O is hot, ten subcategories 0-9, Sun is G2
Hertzprung-Russell diagrams
discovered relationship between spectral and absolute magnitude
red giants
appears red, cooler stars
supergiants
bigger than red giants and brighter
white dwarfs
hot, dim, and small
virgo
the virgin, y and then curves down, bright star spica
leo
the lion, shaped like a lion with neck coming out, bright star Regulus
Gemini
the twins, two stick figures holding hands, bright stars castor and pollux
cancer
the crab, upside down y, no bright star.
t/f Yellow stars, such as our sun, will one day explode in a supernova.
false
t/f Higher mass stars live longer on the main sequence than low mass stars.
false
Type A stars are hotter than type O stars. t/f
false
The corpse of a low mass star is probably
a white dwarf
t/f After the Sun leaves the main sequence, it will evolve into a red giant.
true
Which of the spectral types of stars spends the least amount of time on the main sequence?
B
The process of accumulating material as described in the protoplanet hypothesis is called
accretion
Three mechanisms of heat transfer are
convection, conduction, and radiation
Which of the following is the correct order for spectral types of stars?
OBAFGKM
What would you conclude if you looked through the eyepiece of a telescope and observed two stars within the field of view, one orange and one light blue?
the blue one is hotter
Star A is a first magnitude star. Star B is a sixth magnitude star. Which star is brighter and by how much?
Star A is 100 times brighter than star B.
t/f The Sun’s energy source is nuclear fusion.
true
A huge cloud of gas and dust is called a
nebula
How far away is a star whose parallax angle is 3/11 arc second?
11/3 parsecs
t/f
In order for the distance to an object to be measured using parallax, it must be viewed from two different locations.
true
How many magnitude 3 stars does it take to get as much light as one magnitude 2 star?
2.5
t/f A blue star on the main sequence will live a long time compared to our sun because it is so massive.
false
The total energy output of a star is called
luminosity
/f
A very large star will undergo several supernova explosions in its lifetime.
false
t/f A star’s absolute magnitude is dependent on its distance from the observer.
false
