Life Of Stars

Question 1

Life of stars (6)

Answer 1

Dark cloud, prestellar core, protostar, tauri star, pre-main sequence star, main sequence star

Question 2

What are nebulae

Answer 2

Uneven mass distribution cloud together

Question 3

Three types of nebulae, the colour, how they emit light, and one example

Answer 3

1. Emissive nebulae, red, hydrogen, hot, M42 Orion Nebula
2. Reflective nebulae, blue, reflect light, Witch Head nebula
3. Dark nebula, dark, block light, Horsehead nebula

Question 4

What force causes collapsing during the formation of nebulae

Answer 4

Gravitational force

Question 5

What forces resists collapse during the formation of nebulae

Answer 5

Thermal motion, turbulence, rotational motion (most cannot collapse on its own)

Question 6

Shockwave

Answer 6

From supernovae, galaxy collisions, radiation from young stars-radius decreases-gravitational force increases-unstable-denser parts of the nebula collapses-fragmentation

Question 7

Protostars

Answer 7

Hot enough to emit infrared radiation, but not nuclear reaction
Will become a main sequence star when it gets hot enough (accord google
Protoplanetary disk

Question 8

Main sequence stars

Answer 8

Nuclear fusion (a type of nucleosynthesis)
thermal pressure stops the story from further collapsing
Generate energy by fusing hydrogen into helium and a small mass (4 protons => 1 helium + 2 positrons + 2 neutrinos + energy)

Question 9

How heat is transferred to outer layers of main sequence star

Answer 9

Small: convection
Sun size: radiation then convection
Large: convection then radiation

Question 10

Hot to cold Morgan Keenan system

Answer 10

O B A F G K M

Question 11

Brown dwarf

Answer 11

Failed stars
original mass not large enough to conduct nuclear fusion in a stable state

Question 12

Red giant

Answer 12

Thermal pressure decreases (hydrogen used up)
Core contracts
Heats up layer outside core
Hydrogen shell triggers nuclear fusion
Outer shell expands
Used up helium
Nucleosynthesis of carbon then oxygen
Not hot enough to carry out further nuclearsynthesis
low gravity at surface
outer layers planetary nebula
core white dwarf (high temp low luminosity)

Question 13

White dwarf

Answer 13

Slowly, emit energy away, turns into a black dwarf Chandrasekhar limit (1.4 solar masses beyond will collapse even further)

Question 14

Massive stars, supergiants

Answer 14

Nuclepsynthesis until iron
no more nuclear fusion at core- gravitational force overpowers
everything collapses towards core very quickly
supernova (further nucleosynthesis from the superlarge compressive force) supernova remnant
Core becomes a neutron star or a black hole