Classificati
HR diagram Star clusters
on
Terms
Life cycle
Life Cycles 2
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Temperature
The star's color index is a
quick way of determining its
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Sun
The most famous G type star
is:
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A white dwarf
Which is hotter, a main
sequence star with an
ablsolute magnitude of M=8
or a white dwarf?
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It’s mass
What is the single most
important characteristic in
determining the course of a star's
evolution?
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Type G2 star, middle of HR diagram-average size
and luminosity, end of life will be white dwarf,
only known star to support a planet with life.
Why is our star (the sun) frequently referred to
as an “average” star? Compare the important
physical characteristics of the Sun with the most
common types of stars.
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About the middle of the main sequence
On the HR Diagram, the sun
lies where?
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At the top right of the diagram
Where on the H-R diagram,
are red giants like
Betelgeuse?
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In the lower left of the diagram
On the HR diagram, white
dwarfs are where?
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Luminosity and absolute
brightness
The HR diagram plots ____ and
________ against spectral type and
temperature
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Above and to the right of the main sequence.
On an H-R diagram where would a
protostar lie in comparison to the main
sequence?
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The stars are in old age (Red Giants) and
there are hundreds of thousands to millions
of stars in a cluster.
Describe globular star
clusters
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Massive blue main sequence stars
The brightest stars of a young
open cluster will be
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Red Giants
In globular clusters the
brightest stars will be
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Stars that are in clusters are of similar age,
(also composition and distance) from Earth.
Why are star clusters a great
way for us to study star
evolution?
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Collisions and physical interactions that can
include mergers of object.
What can occur in star
clusters because of the
number of stars that are close
together.
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Brown Dwarfs
A cloud fragment too small to form a star
is called a
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Hydrogen
(molecular)
The most common molecule in
a molecular cloud is
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Gravitation
What is the force that keeps a
main sequence star from
blowing apart?
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O type
What spectral type of star is
most recently formed if it is
still around today
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The more massive the faster it uses up its
fuel and the shorter its lifetime
What is the relationship
between star mass and how
long it lives?
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The igniting of nuclear fuel at 10 millionK
What process marks the birth
of a new star (protostar to an
actual star) ?
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Stars live too long to be observed from birth
to death
Why is it hard to study the
life cycle of one star?
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It fragments into smaller clouds that form
into many stars
How does an interstellar gas
cloud first begin to form
hundreds of stars
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Luminosity decrease and temperature
increases
What happens to luminosity and
temperature as an object plotted on the HR
diagram moves through stages 4-7
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An interstellar cloud is disturbed and begins to
gravitationally collapse, fragments,It heats up and
spins faster. When the core temperature reaches 100
mill K, nuclear fusion begins (H into He). When
outward pressure equals inward pressure the star
enters the main sequence.
Outline the process of star
formation from interstellar
cloud to main sequence
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Starlight scattered by
dust particles
A reflection nebula is cause by
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T Tauri
Strong winds develop
during which phase of
a protostar?
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When a protostar in about
to become a main
sequence star
When does the T Tauri
star occur?
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They are young enough to not have most
of their hydrogen not fused into helium.
They do not evolve off until helium is
built up. Most of stars life time is spent
as a main sequence star.
Why is the largest group of stars the
main sequence stars?
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Molecular clouds are cool interstellar clouds(which are bigger
than our solar system)they are important because a shock wave
can force them to start forming stars.
What do we mean by molecular
clouds, why are they important
and how do they lead to star
formation?