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Today in History: IAU names Pluto's new moons Kerberos and Styx

7/2/2026

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Summary

Story summary

The International Astronomical Union, the global body governing astronomical nomenclature, announced on 2 July that Pluto’s fourth and fifth moons will be called Kerberos and Styx. Kerberos, a ~19 km satellite discovered in 2011, and Styx, the system’s smallest moon discovered in 2012, complete Pluto’s known moon family.

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Story summary

The International Astronomical Union, the global body governing astronomical nomenclature, announced on 2 July that Pluto’s fourth and fifth moons will be called Kerberos and Styx. Kerberos, a ~19 km satellite discovered in 2011, and Styx, the system’s smallest moon discovered in 2012, complete Pluto’s known moon family.