Physics

Luminosity

Total energy emitted by star

Apparent magnitue

How bright a star appears from Earth

Inverse square law

apparent magnitude changes with distance

First line of Proton-Proton chain

hydrogen and hydrogen combine resulting in deuterium (proton and neutron), + positron and neutrino

2nd line of proton proton chain

Deuterium collides with another hydrogen making helium 3 and releasing a gamma ray

3rd line proton proton chain

helium 3 collide with another helium 3 resulting in helium 4 and 2 split off protons

Nuclear fusion purpose

releases energy inside a star

Gravity

pulls star inward, tries to collapse it

outward pressure

Gas from nuclear fusion pushing outward

When gravity and outward pressure are balanced

Hydrostatic equilibrium - keeps a main sequence star in balance for long time

To calculate distance between galaxies

Astronomers measure how long cepheid variable stars take to brighten and dim

Cepheid 2.

They use this period to determine intrinsic brightness

cepheid 3.

They compare actual brightness with apparent magnitude, then calculate distance

how is redshift established

As universe expands, light is stretched to longer wavelengths which is a redshift

to calculate distance between galaxies

astronomers measure redshift. They use Hubble’s law to estimate distance

Classes of stars

Oh Boy A Failing Grade Kills Me

Big Bang theory

The universe began 17.8 billion years ago in a hot dense state and has been expanding ever since

Why does Big Bang Disprove steady state

Cosmic micro background radiation was discovered which could only occur from a hot dense start

Cepheid variable stars

Supernova 1a

how does a red giant form oxygen and carbon and eventually iron

A red giant forms oxygen and carbon through the process of helium fusion, after exhausting its hydrogen supply in the core. Eventually, it can produce iron during further fusion processes as it undergoes advanced stages of stellar evolution.

Trig parallax

Trig parallax is the method of measuring the distance to nearby stars by observing their apparent shift against more distant background stars as Earth orbits the Sun. This shift, known as parallax, is measured in arcseconds and used to calculate stellar distances.

Stages of a star life cycle

Nebula, Protostar- main sequence, red giant

Nebula

Hydrogen gas

Protostar

Gravity compressed nuclear fusion begins

Main sequence

Hydrostatic equilibrium, energy supplied through nuclear fusion

Red giant

when hydrogen starts to run out so helium fusion begins,

Red Supergiant

When the star gets so big after helium fusion, gravity turns into heat, making the core so hot oxygen and carbon slam into each other, crating layers of eleme