Chapter 15 Flashcards
What is the gas and dust that fill the space between the stars within a galaxy?
Interstellar medium
The evolution of a star depends on what?
Mass
What are small particles or grains of matter distributed throughout interstellar space?
Interstellar dust
What is the dimming of visible and ultraviolet light by interstellar dust?
Interstellar extinction
What is the effect by which stars and other objects, when viewed through interstellar dust, appear redder than they actually are?
Interstellar reddening
What is a discrete, high-density region of the interstellar medium made up mostly of atomic or molecular hydrogen and dust?
Interstellar cloud
What is a low-density region of the interstellar medium that fills the space between interstellar clouds?
Intercloud gas
What are the four components of the interstellar medium?
- Hot intercloud gas
- Warm intercloud gas
- Cold intercloud gas
- Interstellar gas
What is a nebula?
It is any interstellar cloud of gas & dust
Do long wavelengths or short wavelengths penetrate interstellar dust?
Long wavelengths
What is an interstellar cloud composed primarily of molecular hydrogen?
Molecular cloud
What is a very young object that is still contracting before becoming a true star?
Protostar
What is a reflection nebula?
Its the scattered light that shows a blue color around bright stars
What is an emission nebula?
Its a cloud of interstellar gas and dust that emits lights in different colors
What is a cold dark nebula?
Its a nebula that it blocks visible light that is emitted from stars behind it
What are planetary nebula?
They are the ejected envelopes from dying stars
What is meant by the term - ZAMS?
Zero-Age Main Sequence
What is the Zero-Age Main Sequence?
It is where stars start hydrogen fusion
What is a star cluster?
It’s a group of stars that all formed at the same time and in the same general location
Why is understanding the interstellar medium important?
It helps us to understand the creation of the universe
What is a proto-planetary disk?
It’s a rotating ring-shaped disk of dense gas and dust that surrounds a newly formed star
(It look like Target’s logo)
What does the H-R diagram for a young star cluster look like?
A lot of the stars are still forming, so only a few are on the main sequence while the rest are below it
(Look at Chapter 15 slide 58 for visual)
What does the H-R diagram for a middle-aged star cluster look like?
All the low mass stars have become main sequence stars, so the majority of them are on the main sequence while a few are above it
(Look at Chapter 15 slide 59 for visual)
What does the H-R diagram for an old star cluster look like?
A lot of the stars have stopped producing hydrogen in their core, so the majority of them have become red giants/supergiants and are above the main sequence. Only a few remain on the main sequence
(Look at Chapter 15 slide 60 for visual)
