LQ Hydrae
 A visual band light curve for LQ Hydrae. The main plot (adapted from Berdyugina et al.[1]) shows the long-term variation, and the inset plot (adapted from Kiraga[2]) shows the periodic variation. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 32m 25.568s[3] |
| Declination | −11° 11′ 04.69″[3] |
| Apparent magnitude (V) | 7.82[4] (7.79 to 7.86)[5] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | K1Vp[6] |
| B−V color index | 0.933±0.021[4] |
| Variable type | BY Dra[5] |
| Absolute magnitude (MV) | 6.47[6] |
| Details | |
Myr | |
LTT 3510[12] | |
| Database references | |
| SIMBAD | data |
LQ Hydrae is a single
During a 1981 survey of southern stars,
star spots on the surface showed significant evolution over time scales of a few months. Variations in rotational modulation of surface activity suggested the star is undergoing differential rotation.[10]
The high
pre-main sequence star.[14] A strong flare event was observed on December 22, 1993, with an estimated energy release of ~5.7×1033 erg.[11] Additional flares were detected thereafter, with ROSAT X-ray data from 1992 showing a strong flare during that time period.[14] Observations from December 2000 and 2001 showed that the magnetic field of the star is dramatically changing its topology on a time frame of a year or less.[16]
The stellar classification of LQ Hya is K1Vp,[6] indicating it is a K-type main-sequence star with some peculiar features in the spectrum. In some respects it is considered an analog of a young Sun around the age of 60 million years.[1] It shows strong emission of ultraviolet and has been detected in the X-ray band, showing an X-ray emission of 8.8×1029 erg/s and indicating high chromospheric activity levels.[14] The star shows dual magnetic activity cycles with period of 6.8 and 11.4 years,[14] which are somewhat comparable to the solar cycle in the Sun.
References
- ^ .
- Bibcode:2012AcA....62...67K. Retrieved 23 June 2022.
- ^ .
- ^ S2CID 119257644.
- ^ S2CID 125853869.
- ^ Bibcode:1999MSS...C05....0H.
- ^ S2CID 119437322.
- ^ S2CID 125765376, 111.
- ^ .
- ^ Bibcode:1993A&A...276..345J.
- ^ S2CID 10033733.
- ^ "LQ Hya", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-23.
- ^ doi:10.1086/114246.
- ^ S2CID 119518367.
- doi:10.1086/191097.
- S2CID 120518212.
Further reading
- Cole-Kodikara, Elizabeth M.; et al. (September 2019), "Spot evolution on LQ Hya from 2006-2017: temperature maps based on SOFIN and FIES data", Astronomy & Astrophysics, 629: 9, S2CID 121348666, A120.
- Cole, E. M.; et al. (September 2015), "Doppler imaging of LQ Hydrae for 1998-2002", Astronomy & Astrophysics, 581: 9, S2CID 118155166, A69.
- Zhang, Liyun; et al. (October 2014), "Chromospheric activity on late-type star LQ Hya", New Astronomy, 32: 1–5, .
- Cao, Dong-tao; et al. (February 2014), "Chromospheric Activity and Rotational Modulation on the Young, Single K2 Dwarf LQ Hya", The Astronomical Journal, 147 (2): 10, S2CID 120310890, 38.
- Kõvári, Zs.; Weber, M. (June 2004), Forgács-Dajka, E.; Petrovay, K.; Erdélyi, R. (eds.), "Differential rotation of LQ Hya and IL Hya from Doppler imaging", Proceedings of the British-Hungarian N+N Workshop for Young Researchers On Computer processing and use of satellite data in astronomy and astrophysics and 3rd Workshop of Young Researchers in Astronomy & Astrophysics; Hungary, 3-7 February 2004, vol. 14, Publications of the Astronomy Department of the Eötvös University (PADEU), pp. 221–232, Bibcode:2004PADEU..14..221K.
- Livshits, M. A.; Alekseev, I. Yu.; Katsova, M. M. (July 2003), "Butterfly Diagram for Starspots on LQ Hya", Astronomy Reports, 47 (7): 562–572, S2CID 122361382.
- Alekseev, I. Yu.; Kozlova, O. V. (January 2003), "Spots and Active Regions on Emission Stars. III. LQ Hya", Astrophysics (English Translation of Astrofizika), 46 (1): 28–45, S2CID 116908588.
- Donati, J. -F. (January 1999), "Magnetic cycles of HR 1099 and LQ Hydrae", Monthly Notices of the Royal Astronomical Society, 302 (3): 457–481, .
- Saar, S. H.; et al. (1994), Caillault, J.-P. (ed.), "Multiple Epoch Magnetic Surface Images of LQ Hya", The Eighth Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Astronomical Society of the Pacific Conference Series, vol. 64, pp. 661–663, Bibcode:1994ASPC...64..661S.
- Strassmeier, K. G.; et al. (February 1993), "Surface features of the lower atmosphere of HD 82558 (=LQ Hydrae)", Astronomy and Astrophysics, 268: 671–684, Bibcode:1993A&A...268..671S.
- Saar, S. H.; et al. (1992), Giampapa, M. S.; Bookbinder, J. A. (eds.), "Magnetic Surface Images of the BY DRA Star HD 82558", The Seventh Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Astronomical Society of the Pacific Conference Series, vol. 26, pp. 255–258, Bibcode:1992ASPC...26..255S.