The White Dwarfs

Description: Test your knowledge about the fascinating world of White Dwarfs, the dense remnants of stars that have exhausted their nuclear fuel.
Number of Questions: 15
Created by:
Tags: astrophysics stellar evolution white dwarfs
Attempted 0/15 Correct 0 Score 0

What is the primary mechanism responsible for the formation of White Dwarfs?

  1. Nuclear Fusion

  2. Gravitational Collapse

  3. Supernova Explosion

  4. Planetary Nebula Formation


Correct Option: B
Explanation:

White Dwarfs are formed when stars of low to intermediate mass exhaust their nuclear fuel and undergo gravitational collapse, leading to the expulsion of their outer layers.

What is the typical mass range of a White Dwarf?

  1. 0.1 - 1.4 Solar Masses

  2. 1.4 - 3 Solar Masses

  3. 3 - 8 Solar Masses

  4. 8 - 15 Solar Masses


Correct Option: A
Explanation:

White Dwarfs typically have masses ranging from 0.1 to 1.4 Solar Masses, which is the Chandrasekhar Limit, beyond which they undergo further collapse to form Neutron Stars or Black Holes.

What is the primary composition of White Dwarfs?

  1. Hydrogen and Helium

  2. Carbon and Oxygen

  3. Iron and Nickel

  4. Silicon and Magnesium


Correct Option: B
Explanation:

White Dwarfs primarily consist of Carbon and Oxygen, as they have exhausted their Hydrogen and Helium fuel through nuclear fusion processes.

What is the typical size of a White Dwarf?

  1. Similar to Earth

  2. Similar to Jupiter

  3. Similar to Sun

  4. Smaller than Earth


Correct Option: D
Explanation:

White Dwarfs are incredibly dense, with masses comparable to the Sun but compressed into a volume similar to Earth or even smaller.

What is the fate of a White Dwarf that exceeds the Chandrasekhar Limit?

  1. It undergoes a Supernova Explosion

  2. It collapses into a Neutron Star

  3. It becomes a Black Hole

  4. It remains stable and continues to cool


Correct Option: B
Explanation:

If a White Dwarf exceeds the Chandrasekhar Limit, it undergoes a sudden collapse, leading to the formation of a Neutron Star. This process is known as a Type Ia Supernova.

What is the primary energy source of a White Dwarf?

  1. Nuclear Fusion

  2. Gravitational Energy

  3. Thermal Radiation

  4. Magnetic Field Energy


Correct Option: C
Explanation:

White Dwarfs primarily emit energy through thermal radiation, as they have exhausted their nuclear fuel and rely on their residual heat to sustain their luminosity.

What is the typical surface temperature of a White Dwarf?

  1. Below 10,000 Kelvin

  2. 10,000 - 20,000 Kelvin

  3. 20,000 - 30,000 Kelvin

  4. Above 30,000 Kelvin


Correct Option: D
Explanation:

White Dwarfs have surface temperatures ranging from 30,000 Kelvin to over 100,000 Kelvin, making them extremely hot despite their small size.

What is the phenomenon observed when a White Dwarf accretes material from a companion star?

  1. Novae

  2. Supernovae

  3. Neutron Star Collisions

  4. Black Hole Formation


Correct Option: A
Explanation:

When a White Dwarf accretes material from a companion star, it can undergo a sudden outburst, known as a Nova. This occurs due to the release of energy as the accreted material undergoes nuclear fusion on the surface of the White Dwarf.

What is the term used to describe a binary system consisting of a White Dwarf and a Red Giant?

  1. Cataclysmic Variable

  2. Novae System

  3. Symbiotic Binary

  4. Contact Binary


Correct Option: A
Explanation:

A binary system consisting of a White Dwarf and a Red Giant is known as a Cataclysmic Variable. These systems are characterized by periodic outbursts due to the transfer of mass from the Red Giant to the White Dwarf.

What is the name of the first discovered White Dwarf?

  1. Sirius B

  2. Procyon B

  3. 40 Eridani B

  4. Groombridge 1830


Correct Option: A
Explanation:

The first discovered White Dwarf was Sirius B, the companion star to the brightest star in the night sky, Sirius. It was identified as a White Dwarf in 1862 by the American astronomer Alvan Graham Clark.

What is the term used to describe a White Dwarf that has a strong magnetic field?

  1. Magnetic White Dwarf

  2. Pulsar

  3. Black Hole

  4. Neutron Star


Correct Option: A
Explanation:

A White Dwarf with a strong magnetic field is known as a Magnetic White Dwarf. These objects exhibit unique characteristics, such as rapid rotation and the emission of high-energy radiation.

What is the process by which a White Dwarf gradually cools and fades over time?

  1. Nuclear Fusion

  2. Gravitational Collapse

  3. Thermal Radiation

  4. Black Hole Formation


Correct Option: C
Explanation:

White Dwarfs gradually cool and fade over time through the emission of thermal radiation. As they lose heat, their luminosity decreases, and they eventually become faint and difficult to detect.

What is the term used to describe a White Dwarf that is surrounded by a planetary nebula?

  1. Planetary Nebula White Dwarf

  2. Central Star

  3. Proto-Planetary Nebula

  4. Post-AGB Star


Correct Option: B
Explanation:

A White Dwarf that is surrounded by a planetary nebula is known as the Central Star. Planetary nebulae are formed when the outer layers of a star are expelled during its final stages of evolution, revealing the hot core, which is the White Dwarf.

What is the term used to describe a binary system consisting of two White Dwarfs?

  1. Double White Dwarf System

  2. Cataclysmic Variable

  3. Novae System

  4. Symbiotic Binary


Correct Option: A
Explanation:

A binary system consisting of two White Dwarfs is known as a Double White Dwarf System. These systems are important for studying the evolution of White Dwarfs and the potential for mergers and supernovae.

What is the name of the closest White Dwarf to Earth?

  1. Sirius B

  2. Procyon B

  3. 40 Eridani B

  4. Groombridge 1830


Correct Option: A
Explanation:

The closest White Dwarf to Earth is Sirius B, located approximately 8.6 light-years away. It is the companion star to Sirius, the brightest star in the night sky.

- Hide questions