# Q77971980

> RR Lyrae variable star in the constellation Hydra

**Wikidata**: [Q77971980](https://www.wikidata.org/wiki/Q77971980)  
**Source**: https://4ort.xyz/entity/q77971980


## References

1. SIMBAD
2. Machine-learned Identification of RR Lyrae Stars from Sparse, Multi-band Data: The PS1 Sample
3. The Catalina surveys periodic variable star catalog
4. Exploring the variable sky with LINEAR. II. Halo structure and substructure traced by RR Lyrae stars to 30 kpc
5. The SDSS Photometric Catalog, Release 7
6. Gaia Data Release 2
7. The Milky Way's circular velocity curve to 60 kpc and an estimate of the dark matter halo mass from the kinematics of ~2400 SDSS blue horizontal-branch stars