The Distance Latter Flashcards
What is Parallax?
The observed displacement of an object caused by the change of the observer’s point of view.
Why is Parallax used in Astronomy?
To compute the distances of nearby stars.
(How nearby objects appear to move against the background of more distant objects)
What do Astronomers use to measure distances of celestial objects?
Standard Candles
Standard Candles
Anything celestial object with predictable luminosity.
Examples of Standard Candles
Main Sequence Stars, Variable Stars; Cepheids
Relationship Between Luminosity and Distance
High Luminosity = Closer
Low Luminosity = Farther Away
Variable Stars
Stars that change in brightness
Cepheids
Type of Variable Stars with regular luminosity changes. (and pulsate)
What type of stars are Cepheids?
Red Giants (that pulsate)
What is the Leavitt Law?
States that the period-luminosity relationship is linear between pulsating Red Giants.
Predicts luminosity with period.
How do Cepheids relate to the Distance Ladder?
One step of the Distance Ladder.
Distance Ladder
Sequence of methods astronomers use to measure relative distances in the Universe.
Relationship between Cepheid and Parallax
Cepheid distances depend on parallax.
What are Light Curves used for?
Show the brightness of a celestial object over a period of time. (Novae, Supernovae, and Variable Stars)
Why are Cepheids used in Astronomy?
Extremely bright stars that can be seen far away to predict distances of nearby galaxies.
