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)
ABC Mass Center	0.0	...	...	...	...	...	...	...	...
40 Boötis A	28.7	206	0.55	84	>330,000	>110	...	...	...
Center of H.Z. A	1.07	1.07	0	?	...	...	...	...	...
BC Mass Center	19.8	206	0.55	84	...	...	...	...	...
40 Boötis B	~0.003	0.00073	0	?	~330,000	<110	...	...	...
40 Boötis C	~0.005	0.00073	0	?	<330,000	<110	...	...	...
Center of H.Z. BC	~0.7	~0.5	0	0	...	...	...	...	...

NOTE: This animation attempts to relate the orbits and possible habitable zones of Stars A, B, and C in the 40 Boötis AB system to their common center of mass. To enlarge the display, the orbits have been arbitrarily rotated by 45 degrees. Although the initial display shows the system's actual orbital tilt (at an inclination of 84°) 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. The masses assumed for the purposes of this animation are: 1.06 Solar for Star A; 0.98 Solar for Star B; and 0.55 Solar for Star C.

From the perspective of an observer on Earth, Star A and the BC tight binary pair exhibit a very elongated and narrow ellipse whose separation has varied from 4.7" in 1880 to less than 0.4" in 1969 (Kaj Aage Gunnar Strand, 1937; A. Gennaro, 1940; L. Bennendijk, 1955; Worley and Heintz, 1983; and Wulff Dieter Heintz, 1963 to 1997; among others). According to new measurements (Staffan Soderhjelm, 1999) found in the new Sixth Catalog of Visual Orbits of Binary Stars, Stars A and B are separated by an "average distance" of about 48.5 AUs (semi-major axis of 3.8" with a HIPPARCOS distance estimate of 41.6 ly), or more than the average of orbital distance of Pluto in the Solar System. They move in a highly elliptical orbit (e= 0.55) that takes about 206 years to complete. Their orbit is inclined about 84° from the perspective of an observer on Earth. These elements are similar to Heintz's 1997 elements of: P=220.0 years; a=3.70"; e= 0.451; and i=83.7 (Wulff Dieter Heintz, 1997).

44 Boötis classified as an eclipsing variable of W Ursae Majoris type (that also resembles U Pegasi) because Star B has a double-lined, spectroscopic companion that is close enough to be considered a (weak thermal) shallow contact binary (Hill et al, 1989, page 96; and Jan Schilt, 1926). Indeed, Stars B and C are separated by only some 0.008 AU, around three quarters of a million miles (more than one million km) or about three times the distance between the Earth and its Moon. They are revolving in a highly circular orbit (e~ 0) that takes only 6.427 hours to complete. Moreover, from the perspective of an observer on Earth, Stars B and C eclipse each other twice at every revolution (every three hours).