# HZ 21

> star in the constellation Coma Berenices

**Wikidata**: [Q87042492](https://www.wikidata.org/wiki/Q87042492)  
**Source**: https://4ort.xyz/entity/q87042492


## References

1. SIMBAD
2. The Palomar-Green catalog of ultraviolet-excess stellar objects
3. Spectra, colors, luminosities and motions of the white dwarfs
4. Further degenerate stars
5. White dwarfs identified in LAMOST DR 2
6. Optical Multicolor Photometry of Spectrophotometric Standard Stars
7. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
8. DA white dwarfs in Sloan Digital Sky Survey Data Release 7 and a search for infrared excess emission
9. Gaia Data Release 2