Upsilon Boötis

| b-v = +1.518 | u-b = +1.893 Upsilon Boötis is a single, orange-hued star in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from υ Boötis, and abbreviated Upsilon Boo or υ Boo. This is a fourth magnitude star that is visible to the naked eye. Based upon an annual parallax shift of as seen from the Earth, it is located about 243 ly distant. The star is moving closer to the Sun with a radial velocity of −6 km/s.

This is an evolved K-type giant star with a stellar classification of K5.5 III. Astroseismology was used to obtain a mass estimate of 1.11 times the mass of the Sun, while interferometric measurements give a size of about 38 times the Sun's radius. It is radiating about 332 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,920 K. The star is roughly 10 billion years old and is spinning with a projected rotational velocity of 5.1 km/s.

References

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| display-authors=1 | last1=Gutierrez-Moreno | first1=Adelina

| display-authors=1 | journal=The Astronomical Journal