To Get the Distance to a Cepheid Variable Star, Astronomers

question 15

Multiple Choice

To get the distance to a Cepheid variable star, astronomers must take several steps. Which of the following is NOT one of these steps?

• A) observe the star getting brighter and dimmer to establish that it varies
• B) measure the period of variations by timing when the star is brightest and dimmest
• C) estimate the apparent brightness of the star
• D) measure the star's Doppler shift from its spectrum
• E) apply the period-luminosity relationship

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Definitions:

Interspecific Competition

A form of competition between individuals of different species inhabiting the same ecological area.

Intraspecific Competition

Competition among members of the same species for resources such as food, space, and mates, which can influence population dynamics.

Unfavorable Environmental Factor

An external condition that negatively impacts the growth, reproduction, or survival of organisms, such as pollution or extreme temperature.

Competitive Exclusion

A principle that two species competing for the same resources cannot coexist at constant population values if other ecological factors remain constant.