Pi2 Cygni
Pi2 Cygni, Latinized from π2 Cygni, is a possible triple star system in the northern constellation of Cygnus. It is visible to the naked eye about 2.5° east-northeast of the open cluster M39, having an apparent visual magnitude of 4.24. Based upon an annual parallax shift of 2.95 mas, it is located at a distance of roughly 1,100 light years from the Sun.
Pi2 Cygni has been described as a single-lined spectroscopic binary with an orbital period of 72.0162 days and an eccentricity of 0.34. However, a 2020 paper found no radial velocity variations on the timescale of the published orbit. The primary, component A, is a B-type giant star with a stellar classification of B2.5 III. It is a Beta Cephei variable with an estimated 8.4 times the mass of the Sun and around 7.1 times the Sun's radius. The star is roughly 33 million years old and is spinning with a projected rotational velocity of 50 km/s. It is radiating 8,442 times the solar luminosity from its outer atmosphere at an effective temperature of around 20,815 K.
The third member of this system is a magnitude 5.98 star at an angular separation of 0.10 arc seconds along a position angle of 129°, as of 1996.