Star diameter

Definition

Star diameter is the measurement of a star's size from one edge of its surface to the opposite edge, passing through its center. It provides critical information for understanding a star's luminosity, temperature, and overall structure.

5 Must Know Facts For Your Next Test

1. The Sun's diameter is approximately 1.39 million kilometers.
2. Star diameters can range from about 10 kilometers for neutron stars to over 1,000 times that of the Sun for supergiants.
3. The diameter of a star affects its luminosity and surface temperature.
4. Direct measurement of star diameters is challenging and often relies on techniques like interferometry.
5. Knowing the diameter helps in determining other stellar properties such as mass and density.

Review Questions

• What is the approximate diameter of the Sun?
• How does the diameter of a neutron star compare to that of a supergiant?
• Why is it difficult to directly measure the diameters of most stars?

Related terms

Luminosity:

The total amount of energy emitted by a star per unit time.

Interferometry:

A technique used in astronomy to measure small angles and improve resolution by combining signals from multiple telescopes.

Neutron Star:

A type of stellar remnant composed almost entirely of neutrons, typically having a very small diameter (about 10 km) but extremely high density.