Star

Life

Cycles

I. Dark Nebulas: Cold Clouds of gas and dust located in arms of galaxies.

a. Gravity pulls gas and dust together to form protostar (no fusion).

Young Protostars in Dark Nebula

II. MAIN SEQUENCE STARS: Stars that are in the first part of their life cycle, fusing hydrogen to helium.

a. Star size is indirectly proportional to life span.b. Star size affects temperature and color

Size Color SurfaceTemperature

Life Span (yrs)

Small Red 3,000 K Trillions

Average (sun)

Yellow 10,000 K Billions

Massive Blue 40,000 K Millions

Sulaphat and its two companion stars (oval shape), 600 light years away!

MASSIVE BLUE GIANT STARS in constellation

LYRA

III. RED GIANTS: When a main sequence star uses up all of its hydrogen fuel and starts expanding under helium - carbon fusion or other advanced stages of fusion.

Red Giants in old star cluster M80orbiting MilkyWayRED GIANTS

IV.Star Death – when fusion stops at the core and gravity collapses the star.

M.Sequene Star Type

Giant Giant Phase Fusion

Event End

Red Dwarf Red Giant He - C Outer layersexpand out

White Dwarf

Yellow Red Giant He - C Outer layersexpand out

White Dwarf

Blue Super Giants

Heavier elements

Super Nova Neutron starBlack hole

V. WHITE DWARFS - When a red giant runs out of helium to carbon fusion, the outer layers expand and leave a white hot core.

Death of a low to

medium mass star.

This is not a

supernova event.

Zoom Views of M4

White Dwarfs

VI. SUPERNOVA – Explosion of a large super giant by caused by gravity’s crushing force.

VII. Compact Cores – gravity begins to change and destroy matter.

VIII. Evidence for Black Holes• Super fast orbiting stars & gas• Radiation from poles of quasars• Mathematics of Enormous Mass = Gravity

Chandra X-RaySuper fast orbiting stars at the center of our galaxy orbiting something invisible.

Galaxy M83, BLACK HOLE AT CENTER

http://chandra.harvard.edu/photo/chronological.html

http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/22/