Long period variable

A long period variable (LPV) is a type of variable star in which variations in brightness occur over long timescales of months or years. Long period variables are giant stars and brighter, from spectral class F and redwards, but most are red giants and AGB giants, meaning spectral class M, S or C. They are usually deep orange or red.

The following well defined variable star classes use to be counted into the LPV category:

• Mira variables, long rather regular pulsation periods in the range between 80 to 1000 days and grand light variations, from 2.5 magnitudes up to 11,
• semiregular variables, the periods in the same range as Miras, but lower amplitude and often irregularities that makes the period determination hard,
• slow irregular variables, stars similar to the semiregulars, but whose period cannot be determined, because of the irregularity of the light change.

References

• GCVS: vartype.txt