star

Table of Contents

Introduction & Top Questions
General considerations
- The Sun as a point of comparison
  - Variations in stellar size
  - Stellar activity and mass loss
- Distances to the stars
  - Determining stellar distances
  - Nearest stars
- Stellar positions
  - Basic measurements
  - Stellar motions
Light from the stars
- Stellar magnitudes
  - Measuring starlight intensity
  - Stellar colours
  - Magnitude systems
  - Bolometric magnitudes
- Stellar spectra
  - Line spectrum
  - Spectral analysis
  - Classification of spectral types
- Bulk stellar properties
  - Stellar temperatures
  - Stellar masses
    - Visual binaries
    - Spectroscopic binaries
    - Eclipsing binaries
    - Binaries and extrasolar planetary systems
    - Mass extremes
  - Stellar radii
  - Average stellar values
- Stellar statistics
  - Hertzsprung-Russell diagram
  - Estimates of stellar ages
  - Numbers of stars versus luminosity
  - Mass-luminosity correlations
- Variable stars
  - Classification
  - Pulsating stars
  - Explosive variables
  - Peculiar variables
Stellar structure
- Stellar atmospheres
- Stellar interiors
  - Distribution of matter
  - Source of stellar energy
Star formation and evolution
- Birth of stars and evolution to the main sequence
- Subsequent development on the main sequence
- Later stages of evolution
  - Evolution of low-mass stars
  - Origin of the chemical elements
  - Evolution of high-mass stars
- End states of stars
  - White dwarfs
  - Neutron stars
  - Black holes

References & Edit History Related Topics

Images & Videos

Open cluster NGC 290

imaging using ultraviolet light

Learn about the different types of stars categorized according to their mass and temperature - red dwarfs, red giants, supergiants, white, and brown dwarf stars

stellar distances

illustration depicting the light curve of Algol

extrasolar planet Kepler-16b

Fomalhaut and dust belt

brown dwarf 2MASSWJ 1207334−393254

Hertzprung-Russell diagram

Hertzsprung-Russell diagram

Small Magellanic Cloud

Cepheid variables

supernova 1987A

limb darkening in the Sun

stellar evolution

Orion Nebula (M42)

W5 Star Formation Region

evolution of a Sun-like star

black hole in M87

Photosphere of the Sun with limb darkening, image taken by the Solar and Heliospheric Observatory satellite, Oct. 29, 2003.

The star-formation history of the Milky Way Galaxy.

The habitable zones (green) for stars that are like the Sun (middle), hotter than the Sun (top), and cooler than the Sun (bottom). The red areas are those in which liquid surface water would be lost as a result of a runaway greenhouse effect, and the blue areas are those in which liquid surface water would be completely frozen.

Stellar parallax.

$Understand how diffraction of light affects stellar images$

Learn about Subrahmanyan Chandrasekhar's elucidation in understanding black holes

Know about the various methods used to discover numerous exoplanets

Know about the various historical supernovae - GRB 111209A, V838 Monocerotis, N 63A, and SN 1006

Explore exoplanets and the techniques used to detect them

Discover how the Gaia satellite helps map the stars in space

What are the three types of galaxies?

Discover why the sky is dark at night and why space appears dark

Listen to astrophysicist Neil deGrasse Tyson narrate a brief history of the formation of the universe, from the big bang to the present

View an animation to understand the difference between supernovae and neutron stars

The scale of the universe: Earth's solar system and beyond

For Students

Cepheid variables

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Written and fact-checked by The Information Architects of Encyclopaedia Britannica

Last Updated: Jun 27, 2025

News •

Astronomers Witness a Cosmic Horror: Roaming Black Hole Caught Devouring Star 600 Million Light-Years Away • June 26, 2025, 11:34 PM ET (SciTechDaily)

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Astronomers discover black hole ripping a star apart inside a galactic collision. 'It is a peculiar event' • May 31, 2025, 12:54 AM ET (Space)

Photos and Videos

Open cluster NGC 290

imaging using ultraviolet light

stellar distances

illustration depicting the light curve of Algol

extrasolar planet Kepler-16b

Fomalhaut and dust belt

brown dwarf 2MASSWJ 1207334−393254

Learn about the different types of stars categorized according to their mass and temperature - red dwarfs, red giants, supergiants, white, and brown dwarf stars

$Understand how diffraction of light affects stellar images$

Learn about Subrahmanyan Chandrasekhar's elucidation in understanding black holes

Know about the various methods used to discover numerous exoplanets

Know about the various historical supernovae - GRB 111209A, V838 Monocerotis, N 63A, and SN 1006

See All Videos and Images →

Topics

stellar diameter stellar density scintillation Vindemiatrix U Cephei main sequence star Celaeno high-velocity star Epsilon Eridani shell star chemical element subatomic particle atom galaxy solar system nebula cosmic microwave background small body planet X-ray source

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Key People

Frank Schlesinger

American astronomer

Herbert Hall Turner

British astronomer

Edward Emerson Barnard

American astronomer

Henry Draper

American astronomer

William Herschel

William Herschel

British-German astronomer

Tycho Brahe

Tycho Brahe

Danish astronomer

Hans Bethe.

Hans Bethe

American physicist

Lev Davidovich Landau

Lev Davidovich Landau

Russian physicist

Friedrich Wilhelm Bessel

Friedrich Wilhelm Bessel

German astronomer

Arthur Stanley Eddington.

Arthur Eddington

British scientist

Eudoxus of Cnidus

Greek mathematician and astronomer

Cecilia Payne-Gaposchkin

British-born American astronomer

Otto Struve

American astronomer

Chandrasekhar, Subrahmanyan

Subrahmanyan Chandrasekhar

American astronomer

Karl Schwarzschild

Karl Schwarzschild

German astronomer

Williamina Paton Stevens Fleming

American astronomer

Otto Heckmann at the European Southern Observatory's (ESO's) one-metre Schmidt telescope at La Silla, Chile, 1971.

Otto Heckmann

German astronomer

Hertzsprung, c. 1930

Ejnar Hertzsprung

Danish astronomer

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Pol Swings

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Jacobus Cornelius Kapteyn

Dutch astronomer

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View of the Andromeda Galaxy (Messier 31, M31).

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