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Author Question: What distance method did Edwin Hubble use to determine the distance to local galaxies? a. Hubble ... (Read 72 times)

melly21297

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on: Jul 27, 2018
What distance method did Edwin Hubble use to determine the distance to local galaxies?
 
  a. Hubble law
  b. supernova observations
  c. period-luminosity relationship of variable stars
  d. parallax

Question 2

Why is there a lower end to the main sequence?
 
  What will be an ideal response?


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Brenm

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Reply #1 on: Jul 27, 2018
Answer to Question 1

c

Answer to Question 2

The mass-luminosity relation tells you why the main sequence must have a lower end. Low-mass objects have lower pressures and temperatures in their cores, and those with less than about 0.08 solar mass are too cool to allow hydrogen fusion.


melly21297

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Reply 2 on: Jul 27, 2018
Excellent

kswal303

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Reply 3 on: Yesterday
Thanks for the timely response, appreciate it

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