21390+5729
- Unique Name: 21390+5729STF2816AD
- RA: 21 38 57.61
- Dec: +57 29 20.5
- Discoverer: STF
- Discoverer Number: 2816
- Components: AD
- First year: 1783
- Last year: 2012
- Observations: 101
- First position angle: 344
- Last position angle: 338
- First separation: 18.6
- Last separation: 19.8
- Mag first component: 5.73
- Mag second component: 7.53
- Spectral type: O6f
- Primary proper motion RA: -2
- Primary proper motion DEC: -5
- Secondary proper motion RA: -2
- Secondary proper motion DEC: -4
- Durchmusterung:
- Notes: N D
