Orbital Distance (a=AUs)	Orbital Period (P=years)	Orbital Eccentricity (e)	Orbital Inclination (i=degrees)	Mass (Solar)	Diameter (Solar)	Density (Earths)	Surface Gravity (Earths)	Metallicity (Solar)
AB Mass Center	0.0	...	...	...	...	...	...	...	...
61 Cygni A	39.6	722	0.40	51.85	0.70	0.48-1.05	...	...	0.79
Inner H.Z. Edge A?	0.385	0.286	0	51.85	...	...	...	...	...
Outer H.Z. Edge A?	0.755	0.784	0	51.85	...	...	...	...	...
61 Cygni B	46.8	722	0.40	51.85	0.63	0.43-0.80	...	...	0.79
Inner H.Z. Edge B?	0.315	0.223	0	51.85	...	...	...	...	...
Outer H.Z. Edge B?	0.617	0.611	0	51.85	...	...	...	...	...

NOTE: This animation attempts to relate the orbits (and possible habitable zones) of Stars A and B in the 61 Cygni AB system to their common center of mass. To enlarge the display, the orbits have been arbitrarily rotated by 135 degrees. Although the initial display shows the system's estimated orbital tilt (at an inclination of 51.85° - F.J. Josties) from the visual perspective of an observer on Earth, the orbital inclination of any planet that may be discovered someday around either star would likely be different from those of the habitable zone orbits depicted here.

In 1830, Friedrich Georg Wilhelm Struve (1793-1864) made the first measurements of the star as a binary system. It is now known that 61 Cygni A and B orbit each other at an "average" distance (semi-major axis) of 86.4 times the Earth-Sun distance, or about 86 astronomical units (AUs) -- which is more than twice Pluto's orbital distance in the Solar System. The star and its stellar companion B have a highly elliptical orbit (e= 0.40) that swings them between 51.7 and 121.0 AUs apart in an orbit that lasts about 722 years, at an inclination of 51.85° (Frederick Jerrold or "Jerry" Josties, 1980; in the Fourth Catalog of Orbits of Visual Binaries, Worley and Heintz, 1983 -- see Alcyone Software's web page on 61 Cygni). While the new Sixth Catalog of Orbits of Visual Binaries seems to have an error in its citation, the older Fifth Catalog provided orbital elements of: a=24.4", 85.2 AUs at 11.4 ly distance; P=659 years; e=0.48; and i=126° (Kisselev et al, 1997).