21390+5729
- Unique Name: 21390+5729MIU 2Aa,Ab
- RA: 21 38 57.61
- Dec: +57 29 20.5
- Discoverer: MIU
- Discoverer Number: 2
- Components: Aa,Ab
- First year: 1992
- Last year: 2005
- Observations: 11
- First position angle: 68
- Last position angle: 248
- First separation: 0.1
- Last separation: 0.1
- Mag first component: 5.73
- Mag second component: 0.0
- Spectral type: O6f
- Primary proper motion RA: -3
- Primary proper motion DEC: -2
- Secondary proper motion RA:
- Secondary proper motion DEC:
- Durchmusterung: +56 2617
- Notes: N
