Spectroscopic binary

Definition

A spectroscopic binary is a binary star system in which the stars are too close together to be resolved individually through a telescope. Instead, their presence is inferred by observing Doppler shifts in their spectral lines as they move around their common center of mass.

5 Must Know Facts For Your Next Test

1. Spectroscopic binaries are detected using the Doppler effect, which causes periodic shifts in the wavelengths of their spectral lines.
2. The orbital period and velocities of the stars in a spectroscopic binary can help determine their masses.
3. Spectroscopic binaries often appear as single points of light because the stars are not spatially resolvable.
4. These systems can have either single-lined or double-lined spectra, depending on whether one or both stars' spectra can be observed.
5. Studying spectroscopic binaries is crucial for understanding stellar masses and testing theories of stellar evolution.

Review Questions

• What method is used to detect spectroscopic binaries?
• How does observing a spectroscopic binary help astronomers determine stellar masses?
• What distinguishes a single-lined spectroscopic binary from a double-lined one?

Related terms

Doppler Effect:

The change in frequency or wavelength of a wave in relation to an observer moving relative to the source of the wave.

Binary Star System: A system of two stars orbiting around their common center of mass.

Stellar Spectroscopy:

The study of the spectrum of starlight to determine various properties such as composition, temperature, density, mass, distance, luminosity, and relative motion.