# TW Herculis

> RR Lyrae variable star in the constellation Hercules

**Wikidata**: [Q76892247](https://www.wikidata.org/wiki/Q76892247)  
**Source**: https://4ort.xyz/entity/tw-herculis


## References

1. SIMBAD
2. Summary of delta-S metallicity measurements for bright RR Lyrae variables observed at Lick Observatory and KPNO between 1972 and 1987
3. General Catalogue of Variable Stars, 3rd ed.
4. Mid-infrared period-luminosity relations of RR Lyrae stars derived from the AllWISE Data Release
5. Gaia Data Release 2
6. Automated variable star classification using the Northern Sky Variability Survey
7. Characteristics of bright AB-type RR Lyrae stars from the ASAS and WASP surveys
8. The Tycho-2 catalogue of the 2.5 million brightest stars
9. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
10. Gaia Early Data Release 3
11. On the Use of Field RR Lyrae as Galactic Probes. III. The α-element Abundances