Lambda Hydrae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
λ Hydrae
Hydra constellation map.svg
Red circle.svg

Location of λ Hydrae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Hydra
Right ascension 10h 10m 35.27667s[1]
Declination −12° 21′ 14.6938″[1]
Apparent magnitude (V) 3.61[2]
Spectral type K0III[2]
U−B color index 0.92[3]
B−V color index 1.00[3]
Radial velocity (Rv) 19.4[2] km/s
Proper motion (μ) RA: -201.27[1] mas/yr
Dec.: -99.63[1] mas/yr
Parallax (π) 28.98 ± 0.83[1] mas
Distance 113 ± 3 ly
(34.5 ± 1.0 pc)
Absolute magnitude (MV) 0.88
Primary Lambda Hydrae A
Companion Lambda Hydrae B
Period (P) 1585.8 days
Semi-major axis (a) 16.79 mas
Eccentricity (e) 0.138
Inclination (i) 79.49°
Longitude of the node (Ω) 249.62°
Periastron epoch (T) 2448664.3906
Argument of periastron (ω)
Other designations
λ Hya, 41 Hya, BDD-11° 2820, HD 88284, HIP 49841, SAO 155785, HR 3994, GC 13982, TYC 5485-1310-1
Database references

λ Hydrae, Latinised as Lambda Hydrae, is a spectroscopic binary[5] star in the constellation Hydra. Its apparent magnitude is 3.61.[6] Located around 34.51 parsecs (112.6 ly) distant,[1] the primary is an orange giant of spectral type K0IIICN+1,[7] a star that has used up its core hydrogen, has expanded, and has an excess of carbon and nitrogen.


  1. ^ a b c d e f van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c "lam Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 December 2016. 
  3. ^ a b Jennens, P. A. (1975). "A new photometric metal abundance and luminosity calibration for field G and K giants". Monthly Notices of the Royal Astronomical Society. 172: 667–679. Bibcode:1975MNRAS.172..667J. doi:10.1093/mnras/172.3.667. 
  4. ^ ESA (1997). "The Hipparcos and Tycho Catalogues". VizieR On-line Data Catalog. Bibcode:1997yCat.1239....0E. 
  5. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. Bibcode:2008MNRAS.389..869E. arXiv:0806.2878Freely accessible. doi:10.1111/j.1365-2966.2008.13596.x. 
  6. ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D. 
  7. ^ Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. Bibcode:2006AJ....132..161G. arXiv:astro-ph/0603770Freely accessible. doi:10.1086/504637.