This document discusses how stars are classified based on their color, size, chemical composition, brightness, and location in the Hertzsprung-Russell diagram. It also describes the life cycles of stars from their birth as nebulae or protostars through their main sequence lifetimes fueled by nuclear fusion, to their deaths as red giants, planetary nebulae, white dwarfs, neutron stars, pulsars, or black holes depending on their original size.

1. Stars 6th Grade Science

2. Classifying Stars Color Red Star = 3,200 °C Yellow Star = 5,800 °C Blue Star = 20,000 °C Size Tiny = Neutron Star (Size of city) Small = Dwarf Star (Size of Earth) Medium = Size of our sun (100 Earths) Large = Giant Star (100 times bigger than our sun) Massive = Supergiants Star (400 times a giant star)

3. Classifying Stars Chemicals Amounts ¾ Hydrogen ¼ Helium Small amounts of other gases (Each star has different amounts of these) Spectrograph Spread out light to see all of colors Chemicals absorb some light (appear black bands)

5. Classifying Stars Brightness Apparent Brightness How bright is the star in our sky at night Absolute Brightness How bright would it be if placed next to our sun

6. Measuring Distances Light Year Distance light can travel in one year 300,000 Km/Sec 9,500,000,000,000 km

7. Measuring Distances Parallax Apparent change in position when you look at from different places

8. Hertzsprung-Russell Diagram (H-R) Measures color and absolute brightness Main Sequence (90% of all stars)

9. Hertzsprung-Russell Diagram (H-R)

10. Hertzsprung-Russell Diagram (H-R) Betelgeuse = Red Supergiant Rigel = Blue Supergiant

11. Lives of Stars Not really ALIVE – just used as an analogy Birth Nebula (Large cloud of gas) Protostar (large collection of gas) Fusion Powered Hydrogen smashed to Helium

12. Lives of Stars Length of lifetime. Small Stars burn slowly 200 billion years (200,000,000,000) Medium Stars burn medium (like our sun) 10 billion years (10,000,000,000) Large Stars burn fast 10 million years (10,000,000)

13. Lives of Stars Death Low and Medium size stars RED GIANT (Huge star) as fuel runs out PLANETARY NEBULA - Throws away out layers WHITE DWARF - Remaining hot glowing center BLACK DWARF – Glow is gone

14. Lives of Stars Death Large size stars (twice size of sun) SUPERGIANT (Enormous star) as fuel runs out SUPERNOVA- Explosive release of out layers NEUTRON STAR- Remaining hot glowing center PULSAR – Spinning in space (100 times per second

15. Lives of Stars Death Massive size stars (40 times bigger than sun) SUPERGIANT (Enormous star) as fuel runs out SUPERNOVA- Explosive release of out layers BLACK HOLE – Star is gone leaving only gravity behind