BROWN DWARF

About

They are celestial objects in between the  size of a giant planet like Jupiter and a small star. 

Astronomers classify any object between 15 times the mass of Jupiter and 75 times the mass of Jupiter as a brown dwarf. 

They are dubbed as failed stars as in the given range of masses, the objects are not able to sustain the fusion of hydrogen like a regular star.

Most of the brown dwarfs discovered to date are parts of a binary system. 

In a binary system, two stars orbit around one another as in the case of the planets of our solar system that orbit our star, the Sun.

Naming of the object

They have been given the name not from the colour of light they emit but because their size falls between white dwarf stars and dark planets. 

Colour:

They appear in different colours depending on the  temperature in their body. 

The warmest ones are orange or red in colour, while cooler brown dwarfs appear magenta or black in colour.

Clouds: 

They also might have clouds made from precipitates in their atmospheres. 

Clouds on brown dwarfs are much hotter than earth and they are likely made up of hot silicate particles unlike the water particles which make up our clouds.

White dwarfs 

Red dwarfs

Brown dwarfs

White dwarfs are the end products of most stars.

Red dwarfs are normal low mass stars with hydrogen fusion capability.

They re objects that are too small to sustain hydrogen fusion in their cores and are often referred to as "failed stars"

They have a short lifespan which might go billions of years.

They have a long lifespan which goes trillions of years.

Their life span is indefinite.

PRACTICE QUESTION

Q.Consider the following statements about the “Brown dwarf” recently seen in the news: 

1. They are celestial objects in between the  size of a giant planet and a small star. 
2. They are not able to sustain the fusion of hydrogen like a regular star.
3. They appear in different colours depending on their size. 

How many of the above statements is/are correct?

A.Only one

B.Only two

C. All Three

D.None

Answer: B

Explanation:

Statement 1 is correct: 

They are celestial objects in between the  size of a giant planet like Jupiter and a small star. 

Astronomers classify any object between 15 times the mass of Jupiter and 75 times the mass of Jupiter as a brown dwarf. 

They have been given the name not from the colour of light they emit but because their size falls between white dwarf stars and dark planets.

Statement 2 is correct: 

They are dubbed as failed stars as in the given range of masses, the objects are not able to sustain the fusion of hydrogen like a regular star.

Most of the brown dwarfs discovered till date are parts of a binary system. 

In a binary system two stars orbit around one another  as in the case of the planets of our solar system that orbit our star, the Sun.

Statement 3 is incorrect: 

They appear in different colours depending on the  temperature in their body. 

The warmest ones are orange or red in colour, while cooler brown dwarfs appear magenta or black in colour.