The celestial coordinates of the star ζ Leonis are right ascension 10^h 16^m, declination +24°; the coordinates of the star λ Ursae Majoris are right ascension 10^h 16^m, declination +43°. Measured along the shortest angle in the sky between the two stars, ζ Leonis is:

Question

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To compare the positions of two celestial objects on the sky, we need to look at their declinations and right ascensions. The declination of ζ Leonis is smaller than the declination of λ Ursae Majoris (+24° vs. +43°), which means that ζ Leonis is located south of λ Ursae Majoris. Both stars have the same right ascension (10h 16m), which means they share the same meridian circle. However, ζ Leonis has a smaller declination, which means it is closer to the celestial equator (the imaginary circle on the sky perpendicular to the meridian), while λ Ursae Majoris is closer to the North Celestial Pole. Therefore, the shortest angle between the two stars will be measured along a great circle passing through the celestial equator and the two stars. This circle will cross the meridian between the two stars at an angle that is closer to the horizon for ζ Leonis (because it's closer to the celestial equator), which means ζ Leonis will be located south of λ Ursae Majoris. Therefore, the correct answer is D, south of λ Ursae Majoris.

The Celestial Coordinates of the Star ζ Leonis Are Right