Қазан шоқжұлдызындағы көпжұлдыз жүйесі 16 Cygni

Multiple star in the constellation Cygnus

Starbox observe 2s
| epoch = J2000.0
| constell = Cygnus
| component1 = 16 Cygni A
| ra1 =
| metal fe = 0.101 ± 0.008
| age gyr = 7.07 The orbital elements of the A–C binary are currently unknown. At a distance of 860 AU from A is a third component designated 16 Cygni B. The orbit of B relative to the A–C pair was determined in 1999 and not updated since (as of June 2007): plausible orbits range in period from 18,200 to 1.3 million years, with a semimajor axis ranging from 877 to 15,180 AU. In addition B orbits between 100 and 160 degrees inclination, that is against the A–C pole such that 90 degrees would be ecliptical. Both 16 Cygni A and 16 Cygni B are yellow dwarf stars similar to the Sun. Their spectral types have been given as G1.5V and G3V, with A being a little hotter than the Sun, and B somewhat cooler. The system was within the field of view of the original mission of the Kepler spacecraft, which collected extremely precise photometric data of the stars. From these measurements, asteroseismology models have calculated precise masses of 1.08 and 1.04 times the solar mass for 16 Cygni A and 16 Cygni B respectively, and independent ages of around 7 billion years for each star. The angular diameters together with the asteroseismology models were used to calculate radii of 1.229 and 1.116 times the solar radius for components A and B respectively. Another chemical peculiarity between the stars is in their lithium abundance. Measurements of the lithium abundance in the system show a 4 times higher abundance in component A than in 16 Cygni B. Compared to the Sun, 16 Cygni A has 1.66 as much lithium, while 16 Cygni B has only 0.35. It has been hypothesized that the accretion of about 1 Earth mass of metals by 16 Cygni B soon after the system's formation may have destroyed the lithium in the star's atmosphere.

In 1996 an extrasolar planet in an eccentric orbit was announced around the star 16 Cygni B. The discovery by the radial velocity method was made from independent observations from the McDonald Observatory and Lick Observatory. Like the majority of extrasolar planets detectable from Earth, 16 Cygni Bb was deduced from the radial velocity of its parent star. At the time that only gave a lower limit on the mass: in this case, about 1.68 times that of Jupiter. In 2012, two astronomers, E. Plavalova and N. A. Solovaya, showed that the stable orbit would demand about 2.38 Jupiter masses, such that its orbit was inclined at either 45° or 135°.