Question

Stars which appear single to the naked eye but are double when seen through a telescope are:
A. novas and supernovas
B. binaries
C. asteroids
D. quasars

Answer 1

-In order to this question, first we will mention the name of stars which appear single to the naked eye but are double when seen through a telescope and then we will clarify the reason. And we will discuss much more about those stars.

Complete answer:
Binaries are the stars which appear single to the naked eye but are double when seen through a telescope. They are single to naked eye because they are far from us. But, if we see with a telescope we can observe that there are two or double stars.

A binary star system (formerly known as double stars) is a system in which two gravitationally coupled stars circle around a common centre of mass, following Kepler's laws of motion. The brighter of the two stars is referred to as the primary star, while the other is referred to as a secondary star. In 1802 Sir William Herschel coined the term "binary."

They are categorised as broad pair or close pair based on orbital motion. A wide pair binary is formed when two stars orbit each other at a greater distance from each other. Both stars evolve independently in a broad pair, with relatively little influence from their respective companion. Close or contact pair binaries are defined as two stars orbiting each other so near that mass transfer owing to tidal forces is possible.

Mass transfer from primary to secondary or vice versa can occur in close or contact binaries.In rare cases, the parent star exerts a significant gravitational pull on the secondary star, pulling it completely onto it. Binary systems are also categorised based on their detecting methods. They are:
-Visual Binary System
-Astrometric Binary System
-Spectroscopic Binary System
-Eclipsing Binary System

Hence, the correct option is B.

Note: Binary star systems are essential in astrophysics because orbital calculations may directly calculate the masses of its component stars, allowing other stellar properties like radius and density to be indirectly inferred. This also yields an empirical mass-luminosity relationship (MLR), which can be used to estimate the masses of specific stars.