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Phi2 Hydrae

Phi<sup>2</sup> Hydrae, Latinized from φ<sup>2</sup> Hydrae, is a star in the constellation Hydra. It originally received the Flamsteed designation of 1 Crateris before being placed in the Hydra constellation. Based upon an annual parallax shift of as seen from Earth, it is located roughly 1,110&nbsp;light years from the Sun. The star is faintly visible to the naked eye with an apparent visual magnitude of about 6.1. It forms a triangle with the fainter φ<sup>1</sup> Hydrae and the brighter φ<sup>3</sup> Hydrae, between μ Hydrae and ν Hydrae.

This is an evolved red giant star with a stellar classification of M1&nbsp;III. It is currently on the asymptotic giant branch, and is a semiregular variable that undergoes changes in luminosity according to three pulsation periods, although it is formally still only a suspected variable. The star is radiating an estimated 1,470 times the Sun's luminosity from its photosphere at an effective temperature of .

Phi<sup>2</sup> Hydrae has a faint visual companion: a magnitude 12.20 star at an angular separation of 3.50&nbsp;arc seconds along a position angle of 280°, as of 1959. The companion has a similar Gaia Data Release 3 parallax to Phi<sup>2</sup> Hydrae and is at a distance of .

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