21189+3909
- Unique Name: 21189+3909AG 270
- RA: 21 18 57.53
- Dec: +39 09 46.4
- Discoverer: AG
- Discoverer Number: 270
- Components:
- First year: 1895
- Last year: 2007
- Observations: 21
- First position angle: 122
- Last position angle: 112
- First separation: 4.8
- Last separation: 5.9
- Mag first component: 9.21
- Mag second component: 10.28
- Spectral type: F0
- Primary proper motion RA: 15
- Primary proper motion DEC: -3
- Secondary proper motion RA: 17
- Secondary proper motion DEC: -7
- Durchmusterung: +38 4442
- Notes: D
