Stars and Sun Life Cycle

Low-mass star life cycle stages

Nebula, Main Sequence, Red Giant, Planetary Nebula, White Dwarf.

High-mass star life cycle stages

Nebula, Main Sequence, Super Giant, Supernova, Neutron Star or Black Hole.

Solar Core function

Site of nuclear fusion converting hydrogen into helium and energy.

Radiative Zone

Dense layer where energy moves outward as bouncing light photons.

Convective Zone

Layer where energy moves via convection currents (hot gases rise, cool sink).

Photosphere

The Sun's visible surface with a temperature of about 5,500 °C.

Chromosphere

Thin reddish layer visible during solar eclipses, site of flares.

Corona

The Sun's hot outer atmosphere that is the source of solar wind.

Sun composition

Approximately 75 percent hydrogen and 25 percent helium.

Nuclear fusion equation in the sun

4 H -> He + energy

Spectral classes order from hottest to coolest

O, B, A, F, G, K, M.

Stellar classification of the Sun

G-type star.

What do dark absorption lines in a spectrum indicate?

Specific elements present in the gas absorbing starlight.

Heavy element fusion limit

Fusion releases energy only up to iron.

Supernova

Massive explosion of a dying star creating elements heavier than iron.

What are sunspots?

Cooler, darker regions on the photosphere caused by strong magnetic fields.

Sunspot cycle length

Approximately 11 years.

Effects of solar flares and CMEs on Earth

Auroras, disrupted satellites, and power grid issues.