S Ursae Minoris (S UMi) is a long period variable

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Ursa Minor, ranging from magnitude 7.5 to fainter than 13.2 over a period of 331 days.

References

Ursa Minor M-type giants Mira variables Ursae Minoris, S Emission-line stars 075847 139492 {{var-star-stub