Upsilon Aquarii

Upsilon Aquarii, Latinized from υ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye as a faint star with an apparent visual magnitude of 5.21. Parallax measurements give a distance estimate of 74.8 ly from Earth. This is a high proper-motion star that is drifting closer to the Sun with a radial velocity of –2.3 km/s. It is part of the Hercules-Lyra association.

The primary component is an F-type main sequence star with a stellar classification of F7 V. It is less than a billion years old and is spinning with a projected rotational velocity of 35 km/s. The star has 1.4 times the mass of the Sun and 1.5 times the Sun's radius. It is radiating 3.6 times the Sun's luminosity from its photosphere at an effective temperature of 6,597 K, giving it the yellow-white hue of an F-type star.

The star displays an excess of near infrared radiation, suggesting it has a circumstellar disk of dusty debris. This disk has a mean temperature of $−2.28$ and is orbiting at an estimated radius of $1.49$. A faint stellar companion was detected in 2007 at the Gemini Observatory, with a separation of $3.581$ from the primary. This is equivalent to a physical projected separation of $6,514$, which yields an estimated orbital period of ~486000 days. The debris disk is orbiting close to the dynamically unstable region of this system.