Question

Which variable stars have pulsation periods between 1.5 hours and 1.2 days?

A. Cepheid variables
B. Protostars
C. RR Lyrae variables
D. Nebulas

Answer 1

D. Nebulas is a cloud of dust,
B. Protostars & A. Cepheid variables have longer pulsation periods.
Whereas, C. RR Lyrae variables have pulsation periods between 1.5 hours and 1.2 days. So the answer is C.

Answer 2

Correct answer choice is :

C) RR Lyrae variables

Step-by-step explanation:

RR Lyrae variables are periodical unsteady stars, usually discovered in globular groups. They are accepted as regular lights to measure galactic distances, as a part of the infinite distance ladder. This class of unsteady star is identified after the prototype and glorious example, RR Lyrae. R Lyraes are vibrating parallel section aging stars of phantom class A or F, with a mass of around half the Sun's.