Question

Proxima Centauri and Bernard’s star are very cool, faint and small stars, approximately 1/10th the mass and diameter of the sun. They burn slowly and have an estimated lifetime of 100 billion years categorised as:
Red dwarf
White dwarf
Red giants
Brown dwarf

Answer 1

Red dwarfs are the smallest and coolest kind of star and small in size. White dwarf stars are heavy, they don't possess faintness. The red giant stars are very bright stars and heavy. A brown dwarf also has a mass which is comparable to the mass of Jupiter.

Complete step by step answer: Proxima Centauries are small, low mass, cool and faint stars which are situated 4.244 light years away from the sun in the southern constellation of Centaurs. In Latin, it means the nearest star of Centaurs. Bernard’s stars are about six light years away from the earth which is a part of the constellation of Ophiuchus. It has a very low mass, about one tenth mass of sun. The lifespan of Bernard’s star is between 7 billion to 12 billion years old.
Red dwarfs are the smallest and coolest kind of stars. Red dwarfs cover three-quarters of the stars in the Milky Way. The lifespan of a red dwarf exceeds 10 billion years.
A white dwarf is also known as degenerate dwarf which is mostly composed of electron degenerate matter. A white dwarf is very dense and its mass is comparable to the mass of the sun. The life span is nearly 10 or even 100 billion years.
Red giants stars are luminous giant stars of nearly low mass in a late phase of stellar evolution. They have a lifespan of a few thousand to one billion years.
Brown dwarfs are the stars that have a mass between the most massive gas giant planets and the least massive stars which are approximately 13 to 80 times the mass of Jupiter. They are barely known as stars as they live only for about 10 million years.
Hence, they are known as red dwarfs.
Therefore, option A is correct.

Note: Both Proxima Centauri and Bernard’s star are known as red dwarf stars because of its characteristics similar to red dwarf stars as both are faint in colour, cool, small in size and of very low mass.