white dwarf

Thân thiện

A white dwarf glows faintly in the vast darkness of space.

Definition

Noun: 1. A faint star of enormous density: A white dwarf is the hot, dense, and small remnant core of a low- or medium-mass star that has exhausted its nuclear fuel. It is in the final stage of stellar evolution for such stars, glowing faintly from residual heat as it slowly cools over billions of years.

Usage Examples

• Noun:
  • Our Sun will eventually become a white dwarf.
  • Sirius B is a famous white dwarf, the companion to the bright star Sirius.
  • Astronomers study the composition of a white dwarf by analyzing its light.

Advanced Usage

• "White dwarf cooling curve": In astronomy, this refers to the relationship between a white dwarf's temperature and its age, used as a cosmic clock to estimate the age of stellar populations.
  • By studying the white dwarf cooling curve, scientists estimated the age of the ancient star cluster.
• "Carbon-oxygen white dwarf": This specifies the most common type of white dwarf, whose core is primarily composed of carbon and oxygen.
  • A typical carbon-oxygen white dwarf has a mass comparable to the Sun but a volume similar to Earth's.

Variants and Related Words

• White dwarf star: A full, alternative name.
• Degenerate matter: The state of matter under the extreme pressure inside a white dwarf, where electrons are packed together as densely as possible.
• Planetary nebula: The expanding shell of glowing gas that is often ejected by the star before the white dwarf remnant is revealed.

Synonyms

• Degenerate dwarf (technical synonym)
• Stellar remnant (broader category that includes white dwarfs, neutron stars, and black holes)

Related Concepts

• Chandrasekhar limit: The maximum mass (about 1.4 times the mass of the Sun) a white dwarf can have. A white dwarf exceeding this limit will collapse into a neutron star or black hole.
  • If a white dwarf accretes enough matter from a companion star to exceed the Chandrasekhar limit, it may explode as a Type Ia supernova.
• Black dwarf: A theoretical cold, dark stellar remnant that a white dwarf would become after radiating away all its heat over trillions of years. The universe is not old enough for any black dwarfs to exist yet.

Học thuật

Noun

1. a faint star of enormous density

Từ đồng nghĩa

• white dwarf star