Astrophysics (index)about

variable star

(star that varies in magnitude)

A variable star (or just a variable) 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. Examples: Achernar, AD Leonis, Algol, DQ Tau, GG Tau, HL Tau, Lalande 21185, Rigel, Ross 154, Ross 248, T Tauri, Vega.

Stars generally are at least slightly variable, such as the 0.1% variability of the Sun over the solar cycle. The term microvariable indicates a star showing very slight variability, e.g., small enough that multiple observations must be made to preclude instrument variability and random errors. The term rotational modulation indicates the repeating pattern of variability that is a signature of starspots.

A few of the types:

The details of the observed variation offer clues to the sources of variation, often revealing or confirming models of stellar structure for the given star, for its particular variable-star type, and for stars in general. In this sense, variable stars are analogous to binary stars, which also serve as windows into stellar detail.

(star type,transient type,variable)

Referenced by:
AD Leonis (AD Leo)
asymptotic giant branch (AGB)
Algol (Beta Per)
AU Microscopii (AU Mic)
Bibliographic Catalog of Variable Stars (BCVS)
Cepheid variable (CEP)
contact binary
cataclysmic variable star (CV)
eclipsing binary (E)
Frank Ross's Catalog (Ross)
FU Orionis star (FUor)
General Catalogue of Variable Stars (GCVS)
instability strip
kappa mechanism (κ-mechanism)
KIC 8462852
Lalande 21185
luminous blue variable (LBV)
Messier 15 (M15)
MACHO Project
main sequence star (V)
New Catalogue of Suspected Variable Stars (NSV)
partial ionization zone
pulsating star
Ross 154
Ross 248
RR Lyrae variable (RRL)
stellar designation
T Tauri
T-Tauri star (TTS)
variable star designation