# G 21-15

> star

**Wikidata**: [Q5396188](https://www.wikidata.org/wiki/Q5396188)  
**Source**: https://4ort.xyz/entity/g-21-15


## References

1. SIMBAD
2. Constraints on the initial-final mass relation from wide double white dwarfs
3. Washington Double Star Catalog
4. UBVRI photometric standard stars around the celestial equator: updates and additions
5. Gaia Data Release 2
6. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
7. The Einstein redshift in white dwarfs