What happens in the white dwarf of a star?

A white dwarf is what stars like the Sun become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, this type of star expels most of its outer material, creating a planetary nebula. Only the hot core of the star remains. That means a white dwarf is 200,000 times as dense.

Is a white dwarf star hot or cold?

A white dwarf is very hot when it forms, but because it has no source of energy, it will gradually cool as it radiates its energy away. This means that its radiation, which initially has a high color temperature, will lessen and redden with time.

What are the characteristics of a dwarf star?

dwarf star, any star of average or low luminosity, mass, and size. Important subclasses of dwarf stars are white dwarfs (see white dwarf star) and red dwarfs. Dwarf stars include so-called main-sequence stars, among which is the Sun.

Is a white dwarf a Sun like star?

A low or medium mass star (with mass less than about 8 times the mass of our Sun) will become a white dwarf. A typical white dwarf is about as massive as the Sun, yet only slightly bigger than the Earth.

Why white dwarf is white?

The white dot in the center of this nebula is a white dwarf; it’s lighting up the receding cloud of gas that once made up the star. They are the stellar cores left behind after a star has exhausted its fuel supply and blown its bulk of gas and dust into space.

What happens when white dwarfs collide?

Since a white dwarf consists of degenerate matter, there is no safe equilibrium between thermal pressure and the weight of overlying layers of the star. Because of this, runaway fusion reactions rapidly heat up the interior of the combined star and spread, causing a supernova explosion.

How hot is a red giant?

A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ( M ☉)) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around 5,000 K (4,700 °C; 8,500 °F) or lower.

Is a red giant hotter than the sun?

A red giant is not very hot at its surface, but its core may reach 1 billion degrees Celsius (that’s 100 times hotter than the sun) (Dickin, 2005). Some stars are much more massive than the sun. The stars which are several times bigger than our sun may turn into supernovae.

What are two characteristics of white dwarf star?

White dwarf stars, so called because of the white colour of the first few that were discovered, are characterized by a low luminosity, a mass on the order of that of the Sun, and a radius comparable to that of Earth.

What surrounds a white dwarf star?

The central region of a typical white dwarf star is composed of a mixture of carbon and oxygen. Surrounding this core is a thin envelope of helium and, in most cases, an even thinner layer of hydrogen. A very few white dwarf stars are surrounded by a thin carbon envelope.

Why do white dwarf stars shine?

The infant white dwarf is incredibly hot and bathes the surrounding space in a glow of ultraviolet light and X-rays. Some of this radiation is intercepted by the outflows of gas that have left the confines of the now dead star. The gas responds by fluorescing with a rainbow of colors called a planetary nebula.

What happens to the atmosphere of a white dwarf star?

The heavier atoms in its atmosphere sink, and the lighter ones remain at the surface. Some white dwarfs have almost pure hydrogen or helium atmospheres, the lightest of elements. Also, gravity pulls the atmosphere close around it in a very thin layer. If this occurred on Earth, the top of the atmosphere would be below the tops of skyscrapers.

What is the difference between a white dwarf and Black Dwarf?

A White Dwarf is the result of a death of a small star that wasn’t big enough to go supernova. There is not believed to be any Black Dwarf Stars due to the fact that the amount of time a White Dwarf needs to cool is longer than the age of the universe. The most common type of Dwarf Stars are red.

What is the difference between a yellow and brown dwarf star?

Our Star is classed as a Yellow Dwarf Star even though if you looked at it outside the atmosphere, it is actually white. It only appears yellow because of the atmosphere. Brown Dwarf Stars are stars without the necessary mass to start nuclear fusion and therefore the coolest stars in the universe. What is a Dwarf Star?

Why are there no black dwarf stars?

There is not believed to be any Black Dwarf Stars due to the fact that the amount of time a White Dwarf needs to cool is longer than the age of the universe. The most common type of Dwarf Stars are red. The smaller a star is, the more economic it is with its energy and the longer it will live for.