Instability strip

For the S Doradus Instability Strip, see Luminous blue variable.

The unqualified term instability strip usually refers to a region of the Hertzsprung–Russell diagram largely occupied by several related classes of pulsating variable stars:[1] Delta Scuti variables, SX Phoenicis variables, and rapidly oscillating Ap stars (roAps) near the main sequence; RR Lyrae variables where it intersects the horizontal branch; and the Cepheid variables where it crosses the supergiants.

RV Tauri variables are also often considered to lie on the instability strip, occupying the area to the right of the brighter Cepheids (at lower temperatures), since their stellar pulsations are attributed to the same mechanism.

  1. ^ Gautschy, A.; Saio, H. (1996). "Stellar Pulsations Across the HR Diagram: Part 2". Annual Review of Astronomy and Astrophysics. 34: 551–606. Bibcode:1996ARA&A..34..551G. doi:10.1146/annurev.astro.34.1.551.