G117-B15A[7] is a small, well-observed variable white dwarf star of the DAV, or ZZ Ceti, type in the constellation of Leo Minor.

G117-B15A was found to be variable in 1974 by Richer and Ulrych,[8] and this was confirmed in 1976 by McGraw and Robinson.

[9] In 1984 it was demonstrated that the star's variability is due to nonradial gravity wave pulsations.

As a consequence, its timescale for period change is directly proportional to its cooling timescale, allowing its cooling rate to be measured using astroseismological techniques.

[7] An X-ray source in the constellation Leo Minor is the white dwarf G117-B15A.