21121+4543
- Unique Name: 21121+4543ES 9005BD
- RA: 21 12 09.28
- Dec: +45 41 21.1
- Discoverer: ES
- Discoverer Number: 9005
- Components: BD
- First year: 1913
- Last year: 2011
- Observations: 7
- First position angle: 85
- Last position angle: 84
- First separation: 23.2
- Last separation: 22.4
- Mag first component: 11.4
- Mag second component: 13.9
- Spectral type:
- Primary proper motion RA: -1
- Primary proper motion DEC: -3
- Secondary proper motion RA: 0
- Secondary proper motion DEC: 13
- Durchmusterung:
- Notes: N
