21256+2957
- Unique Name: 21256+2957J 3139
- RA: 21 25 31.35
- Dec: +29 58 57.9
- Discoverer: J
- Discoverer Number: 3139
- Components:
- First year: 1944
- Last year: 2004
- Observations: 4
- First position angle: 335
- Last position angle: 332
- First separation: 6.0
- Last separation: 6.7
- Mag first component: 10.8
- Mag second component: 10.9
- Spectral type:
- Primary proper motion RA: 8
- Primary proper motion DEC: -15
- Secondary proper motion RA: -6
- Secondary proper motion DEC: -2
- Durchmusterung:
- Notes: