Astronomy:Lambda Hydrae
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Short description: Star in the constellation Hydra
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 10h 10m 35.27667s[1] |
| Declination | −12° 21′ 14.6938″[1] |
| Apparent magnitude (V) | 3.61[2] |
| Characteristics | |
| Spectral type | K0IIIbCN0.5[3] |
| U−B color index | 0.92[4] |
| B−V color index | 1.00[4] |
| Astrometry | |
| Radial velocity (Rv) | 19.4[5] km/s |
| Proper motion (μ) | RA: -201.27[1] mas/yr Dec.: -99.63[1] mas/yr |
| Parallax (π) | 30.0232 ± 0.6973[6] mas |
| Distance | 109 ± 3 ly (33.3 ± 0.8 pc) |
| Absolute magnitude (MV) | +0.92[7] |
| Orbit[8] | |
| 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) (secondary) | 238.9° |
| Details | |
| λ Hya A | |
| Mass | 1-2[9] M☉ |
| Radius | 9.7[9] R☉ |
| Luminosity | 39.8[9] L☉ |
| Surface gravity (log g) | 2.64[9] cgs |
| Temperature | 4,656[9] K |
| Metallicity [Fe/H] | +0.25[10] dex |
| Rotational velocity (v sin i) | 1.9[11] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
λ Hydrae, Latinised as Lambda Hydrae, is a spectroscopic binary[12] star in the constellation Hydra. Its apparent magnitude is 3.61 Located around 33.3 parsecs (109 ly) distant. The spiral galaxy NGC 3145 is only 7.8′ away to the southwest.
The primary is an orange giant of spectral type K0IIICN+1,[13] a star that has used up its core hydrogen, left the main sequence, and expanded into a giant. It is considered to be a red clump giant, a cool horizontal branch star that is burning helium in its core.[14]
λ Hydrae has two visual companions, components B and C, 11th and 13th magnitude stars respectively 71″ and 111″ away.[15]
References
- ↑ 1.0 1.1 1.2 1.3 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 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.
- ↑ Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series 71: 245. doi:10.1086/191373. Bibcode: 1989ApJS...71..245K.
- ↑ 4.0 4.1 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 (3): 667–679. doi:10.1093/mnras/172.3.667. Bibcode: 1975MNRAS.172..667J.
- ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode: 1953GCRV..C......0W.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ ESA (1997). "The Hipparcos and Tycho Catalogues". VizieR On-line Data Catalog. Bibcode: 1997yCat.1239....0E.
- ↑ 9.0 9.1 9.2 9.3 9.4 Cruzalèbes, P.; Rabbia, Y.; Jorissen, A.; Spang, A.; Sacuto, S.; Pasquato, E.; Chiavassa, A.; Chesneau, O. et al. (2013). "SPIDAST: A new modular software to process spectrointerferometric measurements". Monthly Notices of the Royal Astronomical Society 432 (2): 1658. doi:10.1093/mnras/stt593. Bibcode: 2013MNRAS.432.1658C.
- ↑ Hinkel, Natalie R.; Timmes, F. X.; Young, Patrick A.; Pagano, Michael D.; Turnbull, Margaret C. (2014). "Stellar Abundances in the Solar Neighborhood: The Hypatia Catalog". The Astronomical Journal 148 (3): 54. doi:10.1088/0004-6256/148/3/54. Bibcode: 2014AJ....148...54H.
- ↑ De Medeiros, J. R.; Da Silva, J. R. P.; Maia, M. R. G. (2002). "The Rotation of Binary Systems with Evolved Components". The Astrophysical Journal 578 (2): 943–950. doi:10.1086/342613. Bibcode: 2002ApJ...578..943D.
- ↑ 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E.
- ↑ 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. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ Alves, David R. (2000). "K-Band Calibration of the Red Clump Luminosity". The Astrophysical Journal 539 (2): 732–741. doi:10.1086/309278. Bibcode: 2000ApJ...539..732A.
- ↑ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.
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