ZTF J1901+1458 (formally ZTF J190132.9+145808.7) is a white dwarf, about 135 light years (41.3 parsecs) away roughly in the direction of Epsilon Aquilae, discovered by the Zwicky Transient Facility circa 2021. It has around 1.3 times the mass of the Sun, nearly the largest expected mass for white dwarfs, which is defined by the Chandrasekhar limit. Its radius is about , roughly the same as Ganymede, and it rotates once every 6.9373843 minutes. Its effective temperature is about .

The object's extreme rate of spin is hard to explain without supposing ZTF J1901+1458 to be the result of a white dwarf merger, near the upper mass limit of a stable end product. Larger white dwarf mergers could be another mechanism of supernova production, which is not necessarily taken into account in how astronomers have traditionally inferred dark energy from supernova observations.

See also List of white dwarfs

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