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Astronomy Year / Week 09 / Tuesday
2/6
Week 09 · Star Colors and Brightness

Tuesday

Real star colors
// Hot stars, cool stars, near and far
⏱ about 15 min

Tuesday: Real star colors

Nova projects three famous stars.

"Betelgeuse, Rigel and Antares!" Rocket reads.

Raven squints at them. "What do you notice? Which ones look red?"

Nova hums. "Hint: use what you learned about heat."

Three famous stars

StarStar groupColor
BetelgeuseOrionred
RigelOrionblue
AntaresScorpiusreddish orange
Star colorTrue or false?
Rigel is a blue star.?
Betelgeuse is a blue star.?
Antares looks reddish orange.?
Rigel is hotter than Betelgeuse.?
WHY THIS EXERCISEA star's color is a clue to how hot it is.
COLOR CLUES
  • Read the question.
  • Tap your answer.
Which star is hotter, Rigel or Betelgeuse?
Antares looks reddish orange. Is it a hot blue star?
Look closely
Star colors are soft and hard to see.
Bright stars show their color best.

Colors are soft

Star colors are not bright like paint.

They are soft hints of color.

Look at a bright star for a slow count of ten.

Then ask: does it look a little red, or a little blue?

STAR DETECTIVE
  • Read the question.
  • Tap your answer.
Which star group has red Betelgeuse?
Which star group has Antares?
Which stars show their color best?
Which is cooler, Antares or Rigel?
LOOK FOR A STAR COLOR
  • Tap a card.
  • Then tap its spot.
1First
2Next
3Then
4Last
Try it
Look at a red crayon and a blue crayon in dim light.
Can you still tell the colors apart?
Star colors are soft, like colors in dim light.
Draw red Betelgeuse and blue Rigel side by side.

You read star colors! Tomorrow we test brightness with flashlights.

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