H-R Diagram (Oh yeah, you’re gonna see it again!)
Interstellar cloud of gas and dust – Birthplaces of stars!
Star Birth (Indie-RockSTARS like our Sun) Protostar – Stage 1. Gas and dust collapses on itself by gravity, balanced by outward gas pressure. Inward gas pressure trying to escape, causing internal temp. & press. to riseInward gas pressure trying to escape, causing internal temp. & press. to rise This causes nuclear fusion to begin!
Main Sequence Fully developed star (like our sun) -most of stars lifetime spent in this stage
Senior Citizen Stars Later in life, stars become Red Giants Star has converted all Hydrogen into Helium. Where is it on H-R diagram?Star has converted all Hydrogen into Helium. Where is it on H-R diagram? Temp. drops, size increases
Senior Citizen Stars Variable Stars – expand and contract, grow bright and fade. Over a period of 1 – 70 daysOver a period of 1 – 70 days Quick for a star that lasts ~10 billion years!
Outer Shell Ejection Later in life, a star will eject the outer shell of Hydrogen, leaving the Helium behind in the core. This fast traveling Hydrogen gas is called a Planetary nebula
Hi-ho, Hi-ho, It’s off to work…. After it’s shell is gone, all that is left is a layer of Helium, and a core of denser Carbon. Gravity pulls star inwardsGravity pulls star inwards Results in very small, very dense dying star, a White Dwarf Low luminosity, low temp.Low luminosity, low temp.
Crab Nebula First noted by Chinese Astronomers in 1054 A supernova remnant!A supernova remnant!
We are all stardust….man.. Supernova ejection cloud travels away quickly, and the intense heat, pressure, electrons, etc. cause all the heavier elements to form in the universe. So, really, we’re all formed from the remains of stars! My head hurts now….My head hurts now….
Pulsars (Neutron Stars) After a star explodes, sometimes only neutrons are left (Guess where the name “Neutron Stars” came from?) Also called Pulsars because they emit radio waves with incredible regularity. Appear to be rapidly rotating neutron star
Pulsar The crab pulsarA slower pulsar Yup, same one they saw in 1054!
Black Holes Some REALLY big stars can continue to collapse after the pulsar stage to become super dense areas of space known as black holes Simply a point in space where gravity concentrates a large mass into a very, very small area
Black Holes Surface of black holes, the point at which no light can escape, is called the Event Horizon Spot in the center, in theory, is called the Singularity
Black Holes Schwarzschild Radius is the theoretical radius at which a spherical body becomes a black hole. R = 2GM/c^2 G=gravitation constant M=mass c=speed of lightG=gravitation constant M=mass c=speed of light Sun = 2 miles Earth = 1 cm (.4 inch)
Supernova recap Supernova recap via Lite-Brite via Lite-Britevia Lite-Brite