21023+3931
- Unique Name: 21023+3931SMY 6AD
- RA: 21 02 20.96
- Dec: +39 30 32.5
- Discoverer: SMY
- Discoverer Number: 6
- Components: AD
- First year: 1862
- Last year: 2012
- Observations: 7
- First position angle: 139
- Last position angle: 141
- First separation: 54.8
- Last separation: 57.1
- Mag first component: 6.62
- Mag second component: 12.61
- Spectral type: K3II-III
- Primary proper motion RA: 2
- Primary proper motion DEC: 1
- Secondary proper motion RA: -8
- Secondary proper motion DEC: -10
- Durchmusterung:
- Notes: N
