Question

Suppose you live at latitude 40°N. Which of the following describes the conditions that make a star

circumpolar?
a. Stars are circumpolar if they have declination > +40°.
b. No stars are circumpolar at this latitude
c. Stars are circumpolar if they have right ascension > 6 hr.
d. Stars are circumpolar if they have right ascension < 6 hr.
e. Stars are circumpolar if they have declination > +50°.

Answer 1

At 40°N latitude, stars with declination greater than +50° are circumpolar, meaning the correct answer is 'e. Stars are circumpolar if they have declination > +50°'.

Step-by-step explanation:

For an observer living at latitude 40°N, a star is considered circumpolar if it never sets below the horizon, remaining visible all night, every night, throughout the year. This condition occurs when a star's declination is within a certain range of the observer's latitude. Specifically, a star is circumpolar if its declination is greater than the observer's latitude subtracted from 90°. Therefore, for a latitude of 40°N, a star would need to have a declination greater than 50° (+90° - 40° = +50°). Hence, the correct answer to which of the following describes the conditions that make a star circumpolar is e. Stars are circumpolar if they have declination > +50°.