Question

Which of the following are properties of the pole star?
(THIS QUESTION HAS MULTIPLE CORRECT OPTIONS)
(A) It lies far from the axis of rotation of Earth
(B) It does not appear to move
(C) It appears to be overhead when seen from either North or South Pole
(D) It can be located with the help of Ursa Major.

Answer 1

Hint: We know that Earth's pole stars are Polaris (Alpha Ursae Minoris), a magnitude-2 star aligned approximately with its northern axis, and a pre-eminent star in celestial navigation, and Polaris Australis (Sigma Octantis), a much dimmer star. Polaris is around 50 times bigger than our sun. It has an estimated diameter of around 44 million miles / 70 million kilometres, and a radius of about 22 million miles / 35 million kilometres. Its mass is estimated to be around 5.4 times that of our sun.

Complete step by step answer
It can be said that the pole star lies close to the axis of rotation of the Earth hence it appears to be fixed in one place. On viewing from either North or South pole it appears to be directly overhead. On extending an imaginary line towards the north from the two stars at the end of the Ursa Major constellation we can locate the Pole star.
Polestar, also spelled pole star, also called (Northern Hemisphere) North Star, the brightest star that appears nearest to either celestial pole at any particular time. Owing to the precession of the equinoxes, the position of each pole describes a small circle in the sky over a period of 25,772 years. It tops almost any list of the most famous stars and constellations in our sky, but the Pole Star is not one of the brightest, like Sirius or Arcturus. Although not notable for its brightness, the Pole Star (aka Polaris or the North Star or the Polar Star) is the brightest star in the constellation of Ursa Minor.

So, the correct answers are option B, option C and option D.

Note: It can be said that there is no bright star near the south celestial pole; the present southern polestar, Polaris Australis (also called Octantis), is only of the 5th magnitude and is thus barely visible to the naked eye. In fact, most of the stars are shining with a steady light. The movement of air (sometimes called turbulence) in the atmosphere of Earth causes the starlight to get slightly bent as it travels from the distant star through the atmosphere down to us on the ground. To our eyes, this makes the star seem to twinkle.