Intrinsic in⋅trin⋅sic    /ɪnˈtrɪnsɪk, -zɪk/ Show Spelled Pronunciation [in-trin-sik, -zik] Show IPA –adjective 1. belonging to a thing by its very nature: the intrinsic value of a gold ring. 2. Anatomy. (of certain muscles, nerves, etc.) belonging to or lying within a given part.

THE LIFE OF A STAR

NEBULA

Nebula cloud of gas and dust Birthplace for new stars and solar systems Gravity contracts to become……

EAGLE NEBULA

PROTOSTAR Nebula core collapses and heats up, nuclear fusion is about to begin

Main Sequence Star Nuclear fusion has begun! H+ H  He + energy Fusion creates HEAT, LIGHT, RADIATION Life in Main Sequence depends on MASS OF STAR Massive = short life in MS Less massive = long life in MS 90% of star’s life is in Main Sequence

MAIN SEQUENCE

Red Giant All Hydrogen in core has fused Helium + helium carbon Star “puffs out” and cools off (produces RED COLOR) Very Bright Cool Temperature

RED GIANT

Planetary Nebula/White Dwarf Core shrinks to its most compact state (white dwarf) HOT! dim Outer layers ejected and form a cool gas/dust shell Planetary nebula

PLANETARY NEBULA WHITE DWARF

WHITE DWARF

Black dwarf No more fusion Hard to detect May take a trillion years- do they exist?

Normal life cycle Birth (nebula) Main sequence (last 10 billion years) H running out Red Giant He running out White dwarf Dies Black dwarf (cold dark mass) fusion

3X MORE MASSIVE THAN THE SUN SUPERSTARS! 3X MORE MASSIVE THAN THE SUN

Start the same way BUT SHORTER LIFE-SPAN Nebula Protostar Main sequence RED SUPERGIANT (larger than red giant)

RED SUPERGIANT

Supernova Outer layers first contract, then explode outward.

SUPERNOVA before/after 1987

SUPER NOVA

Supernova Remnants: Cas A Optical X-ray Cas A is 300 years old. The remnant is about 10 light-years in diameter, and 10,000 light-years away. X-ray: outer shock wave is from the initial supernova explosion ripping through the interstellar medium at 10 million miles per hour. Temperatures may reach 50 million degrees. The inner shock is the ejecta from the SN heating up the circumstellar shell, heating it to 10 million degrees The optical image of Cas A shows matter with a temperature of about ten thousand degrees. Some of these wisps contain high concentrations of heavy elements and are thought to be dense clumps of ejected stellar material. Cas A x-ray and optical images from http://chandra.harvard.edu/photo/0237/

Neutron Star Supernova core contracts to ~ 10-30 km Densest object known! Rapid rotation of star releases repeating bursts of radio signals (PULSARS)

OR….. Black Hole MOST MASSIVE OF ALL STARS become this Gravity causes severe core contraction NOTHING can escape a black hole!

ACCRETION DISK BLACK HOLE

Material pulled from another companion star

MASSIVE STARS (3X SUN) SUPERSTARS!! Nebula Main sequence (last millions of years) Red supergiant Super Nova (1 billion degrees) Neutron star (core, pulsars) Black hole

Size comparison

The End of the Line for Massive Stars Massive stars burn a succession of elements. Iron cannot be fused further. Instead of releasing energy, it uses energy. Fusion stops at Iron, and star collapses under its own weight. The star contains products of the fusion processes.