2 Cygni
{{short description|Star in the constellation Cygnus}}
{{Starbox begin
| name = 2 Cygni
}}
{{Starbox observe
| epoch = J2000
| constell = Cygnus
| dec = {{DEC|+29|37|16.7934}}
}}
{{Starbox character
| type =
| u-b =
| variable =
}}
{{Starbox astrometry
| radial_v = {{Val|−23.60|2.0}}
| parallax = 3.5657
| p_error = 0.1692
}}
{{Starbox detail
| source =
| luminosity_bolometric = 3,354
| temperature = {{Val|16479|219|fmt=commas}}
| gravity = {{Val|3.653|0.035}}
| metal_fe = {{Val|+0.03|0.05}}
| rotational_velocity = {{Val|137|8}}
}}
{{Starbox catalog
| names = {{odlist | BD=+29°3584 | FK5=3550 | GC=26785 | HD=182568 | HIP=95372 | HR=7372 | SAO=87159 }}
}}
{{Starbox reference
| Simbad=2+Cyg
}}
{{Starbox end}}
2 Cygni is a blue-white hued star in the northern constellation of Cygnus, located a few degrees from Albireo. It is a probable astrometric binary; the visible component can be viewed with the naked eye, having an apparent visual magnitude of 4.976. Based upon an annual parallax shift of {{Val|3.6|ul=mas}}, it is located roughly 910 light years from Earth. It has a peculiar velocity of {{Val|23|u=km/s}} and may be a runaway star system.
The stellar classification of the primary is B3 IV, matching a B-type subgiant star. It has seven times the mass of the Sun and about 5.6 times the Sun's radius. The star is 37 million years old with a high rate of spin; it has a projected rotational velocity of 137 km/s. It is radiating 3,354 times the Sun's luminosity from its photosphere at an effective temperature of 16,479 K.
In 2024, imaging detected a candidate companion star at an angular separation of {{val|70|ul=mas}}. It appears to be a main sequence star with an estimated mass of {{val|5.90|0.18|u=Solar mass}}.
References
{{reflist|refs=
{{cite simbad | title=2 Cyg | access-date=2019-01-07 }}
{{Cite Gaia DR2|2038567370506134528 }}
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}}
{{Stars of Cygnus}}
Category:Cygnus (constellation)