Download The Dramatic Lives of Stars

The Dramatic Lives of
Stars
with images from
"The Universe at your Fingertips 2.0"
Astronomical Society of the Pacific
Death
Adulthood
Old age
Childhood
Death leads to raw materials for new stars
Main sequence
Birth of stars
Death of stars
Main sequence
Birth of stars
Death of stars
Main sequence
Carina Nebula
Orion Nebula
Pleiades
Young stars are called “Pre-main sequence” stars. They sit to
the upper right of the main sequence in an HR diagram.
Given the position of young stars in the HR diagram, which of
the following is true? A 0.5 solar mass star mostly:
A.  Grows as it ages
B.  Shrinks as it ages
C. Heats up as it ages
D. Cools as it ages
Given the position of young stars in the HR diagram, which of
the following is true? A 9 solar mass star mostly:
A.  Grows as it ages
B.  Shrinks as it ages
C. Heats up as it ages
D. Cools as it ages
Given the position of young stars in the HR diagram, which of
the following is true? A star like the sun both:
A.  Grows and heats up as it
ages
B.  Grows and cools as it ages
C. Shrinks and heats up as it
ages
D. Shrinks and cools as it
ages
The Main sequence
Main Sequence Star: Sun
Main Sequence Stars come in a range of masses, sizes and temperatures:
The (northern hemisphere) winter night sky
Credit & Copyright:
Jimmy Westlake (Colorado Mountain College)
Some of the brightest main sequence stars in the winter night sky
Castor
Procyon
Sirius
Credit & Copyright:
Jimmy Westlake (Colorado Mountain College)
Have a look at this artist’s depiction of the sizes and
colors of main sequence stars.
Do you notice a relationship between color and size?
How would you plot these stars on an HR diagram?
Where does a star’s energy come
from on the main sequence?
Nuclear fusion fuels stars
Aldebaran: A red giant
Which star is Aldebaran? Any guesses?
Aldebaran: A red giant
Aldebaran
Betelgeuse: A red supergiant
Which star is Betelgeuse? Any guesses?
Betelgeuse: A red supergiant
Which star is Betelgeuse? Any guesses?
Betelgeuse
Betelgeuse: A red supergiant
Only the second image EVER taken of the surface of a star
Where is Aldebaran? Where is Betelgeuse?
Red supergiants
Red giants
Why do giant and supergiant stars
become large and red?
NOT to scale. Red giant stars are MUCH larger
Red giant Aldebaran and the sun to scale
Why do giant and supergiant stars
become large and red?
NOT to scale. Red supergiant stars are MUCH larger
Betelgeuse and sun to scale
What happens when stars are no
longer able to fuse atoms
together?
Ring Nebula
Ring Nebula
White dwarf
How would you describe the color and size of white dwarfs?
Supernova 1987A
Where do you think an exploding supernova would be on
an HR diagram?
Where do you think an exploding supernova would be on
an HR diagram?
Crab Nebula: A supernova remnant
Supernova 1987A
The remnant of SN 1987A
http://spiff.rit.edu/classes/phys230/lectures/star_age/evol_hr.swf