SIMBAD references

Assuming that binaries are formed in three-body interactions in clusters, we wonder whether the process continues after the stars reach the main sequence. We considered the 233 binaries with known orbital elements that are main-sequence members in 69 open clusters, and looked for changes (presumably decreases) in separations or periods and eccentricities. We found none that are statistically significant, indicating that most binaries are fully formed by the time that their primaries reach the main sequence.