Chamukuy — おうしの二重星

Chamukuy, Theta2 Tauri, is an A7 III giant star about 150 light-years away — the brightest member of the Hyades open cluster, the nearest prominent open cluster to the Sun. Chamukuy is a spectroscopic binary with a period of 140.7 days and an A7 V companion. The combined magnitude is 3.40. The star is about 2.6 solar masses and lies in the heart of the V-shaped Hyades asterism that forms the face of Taurus the Bull.

Chamukuy sits at the eye end of the Hyades "V," very near Aldebaran (a foreground star, not actually a Hyades member). In binoculars Chamukuy is unmistakably bright in a field of dozens of Hyades members. The Hyades is the easiest naked-eye open cluster in the entire sky — every star you can count in the V is a Hyades member, about 150 light-years distant and 625 million years old. Best observed November through March.

The name Chamukuy is from the Mayan language, meaning "small bird" — a reference to a celestial bird in Mayan astronomy. The IAU adopted the name in 2017 as part of an effort to recognize indigenous American star names.