Editing Epsilon Eridani (section)

=== Kinematics ===
Epsilon Eridani has a high [[proper motion]], moving −0.976&nbsp;arcseconds per year in [[right ascension]] (the celestial equivalent of longitude) and 0.018&nbsp;arcseconds per year in [[declination]] (celestial latitude), for a combined total of 0.962 arcseconds per year.<ref name=aaa474_2_653 />{{refn|1=The total proper motion μ can be computed from:
: μ<sup>2</sup> = (μ<sub>α</sub> cos δ)<sup>2</sup> + μ<sub>δ</sub><sup>2</sup>
where μ<sub>α</sub> is the proper motion in right ascension, μ<sub>δ</sub> is the proper motion in declination, and δ is the declination.<ref name="birney" /> This yields:
: μ<sup>2</sup> = (−975.17 · cos(−9.458°))<sup>2</sup> + 19.49<sup>2</sup> = 925658.1
or μ equals 962.11.|group="note"|name=total_pm}} The star has a radial velocity of {{convert|+15.5|km/s|mph|abbr=on}} (away from the Sun).<ref name=rgcrv66 /> The [[space velocity (astronomy)|space velocity]] components of Epsilon Eridani in the [[galactic coordinate system|galactic co-ordinate system]] are {{nowrap|(U, V, W)}} = {{nowrap|(−3, +7, −20) km/s}}, which means that it is travelling within the [[Milky Way]] at a mean [[galactocentric distance]] of 28.7&nbsp;kly (8.79&nbsp;kiloparsecs) from the core along an orbit that has an [[orbital eccentricity|eccentricity]] of 0.09.<ref name=ab6_2_308 /> The [[Stellar kinematics|position and velocity]] of Epsilon Eridani indicate that it may be a member of the [[Ursa Major Moving Group]], whose members share a common motion through space. This behaviour suggests that the moving group originated in an [[open cluster]] that has since diffused.<ref name=an325_1_3 /> The estimated age of this group is {{nowrap|500±100 million}} years,<ref name=apj125_4_1980 /> which lies within the range of the age estimates for Epsilon Eridani.

During the past million years, three stars are believed to have come within {{convert|7|ly|pc|abbr=on}} of Epsilon Eridani. The most recent and closest of these encounters was with [[Kapteyn's Star]], which approached to a distance of about {{convert|3|ly|pc|abbr=on}} roughly 12,500 years ago. Two more distant encounters were with [[Sirius]] and [[Ross 614]]. None of these encounters are thought to have been close enough to affect the circumstellar disk orbiting Epsilon Eridani.<ref name=asp2001_227 />

Epsilon Eridani made its closest approach to the Sun about 105,000&nbsp;years ago, when they were separated by {{convert|7|ly|pc|abbr=on}}.<ref name=aaa379 /> Based upon a simulation of close encounters with nearby stars, the binary star system [[Luyten 726-8]], which includes the [[variable star]] [[UV Ceti]], will encounter Epsilon Eridani in approximately 31,500 years at a minimum distance of about 0.9&nbsp;ly (0.29&nbsp;parsecs). They will be less than 1&nbsp;ly (0.3&nbsp;parsecs) apart for about 4,600 years. If Epsilon Eridani has an [[Oort cloud]], Luyten 726-8 could gravitationally [[Perturbation (astronomy)|perturb]] some of its [[Exocomet|comets]] with long [[orbital period]]s.<ref name=potemine10 />{{unreliable source?|date=September 2021}}