Visual binary

Definition

A visual binary is a binary star system where the two stars can be individually resolved through a telescope. This allows astronomers to observe their orbital motion directly over time.

5 Must Know Facts For Your Next Test

1. Visual binaries are important for determining stellar masses by applying Kepler's laws of planetary motion.
2. The separation between the stars in a visual binary can be measured in arcseconds.
3. Many visual binaries have long orbital periods, sometimes taking decades or even centuries to complete one orbit.
4. The first visual binary, Mizar, was discovered in 1650 by Giovanni Battista Riccioli.
5. Observing a visual binary requires precise and sustained measurements due to the slow movement of the stars relative to each other.

Review Questions

• How do astronomers determine stellar masses using visual binaries?
• What is the significance of measuring the separation between stars in a visual binary?
• Why might it take decades to observe one complete orbit in some visual binaries?

Related terms

Spectroscopic Binary: A binary star system where the stars are too close to be resolved individually but can be detected through Doppler shifts in their spectral lines.

Eclipsing Binary: A binary star system where the orbital plane is aligned with our line of sight, causing periodic dimming as one star passes in front of the other.

Kepler's Laws: Three fundamental principles that describe planetary motion, which are also applied to understanding the orbits within binary star systems.