# IK Hydrae

> RR Lyrae variable star in the constellation Hydra

**Wikidata**: [Q80738332](https://www.wikidata.org/wiki/Q80738332)  
**Source**: https://4ort.xyz/entity/ik-hydrae


## References

1. SIMBAD
2. Discoveries on southern objective-prism plates. II. New probable field horizontal-branch stars
3. Gaia Data Release 3
4. Mid-infrared period-luminosity relations of RR Lyrae stars derived from the AllWISE Data Release
5. Gaia Data Release 2
6. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
7. Gaia Early Data Release 3
8. On the Use of Field RR Lyrae as Galactic Probes. III. The α-element Abundances
9. On the Use of Field RR Lyrae as Galactic Probes. II. A New ΔS Calibration to Estimate Their Metallicity