Astrophysics (index)

Variable Star

(star that varies in magnitude)

A Variable Star is a star which becomes dimmer and brighter over time as seen from Earth. This can be due to changes in the star such as brightening or enlarging, or through a change in whatever the light must pass through to reach us.

Stars generally are at least slightly variable, such as the 0.1% variability of the Sun over its 11 year cycle.

A few of the types:

  • Cepheid Variables resonate between larger and smaller.
  • Protostars
  • Polar or AM Herculis Star - Binary Star with Accretion of mass from a Red Dwarf to a White Dwarf with a significant magnetic field.
  • Intermediate Polar or DM Herculis Star - similar to a polar if the magnetic field is weaker or the stars are further apart.
  • BY Draconis Variable (or BY Draconis Star) - apparently Star Spots produce their variability.
  • Flare Star - shows quick variations, e.g., in minutes - generally an M Dwarf (examples: Wolf 359 and Barnard's Star).

(star type,transient,variable)

Referenced by:
AD Leonis (AD Leo)
Algol (Beta Per)
Cataclysmic Variable Star (CV)
Dynamical Instability
Frank Ross's Catalog
Palomar Four-Filter Survey (PC)
Pre-Main-Sequence Star (PMS)
T Tauri
T-Tauri Star (TTS)