The Instability strip is a nearly vertical region in the Hertzsprung–Russell diagram which is occupied by pulsating variable stars (including RR Lyrae variable, Cepheid variable, W Virginis variable, ZZ Ceti variable, RV Tauri variable, Delta Scuti variable, SX Phoenicis variable and rapidly oscillating Ap stars).
The instability strip intersects the main sequence in the region of A and F stars (1–2 solar mass) and extends upwards almost vertically (slightly inclined to the right) to the highest luminosities. The lower part of instability strip appears as the Hertzsprung gap on the Hertzsprung–Russell diagram.
Read more about Instability Strip: Pulsations
Famous quotes containing the words instability and/or strip:
“With one more talent one frequently stands with greater instability than with one less, as a table stands better on three legs than on four.”
—Friedrich Nietzsche (1844–1900)
“Perfect present has no existence in our consciousness. As I said years ago in Erewhon, it lives but upon the sufferance of past and future. We are like men standing on a narrow footbridge over a railway. We can watch the future hurrying like an express train towards us, and then hurrying into the past, but in the narrow strip of present we cannot see it. Strange that that which is the most essential to our consciousness should be exactly that of which we are least definitely conscious.”
—Samuel Butler (1835–1902)