Astronomy:Iota Leonis

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Short description: Star in the constellation Leo
ι Leonis
Location of ι Leonis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Leo
Right ascension  11h 23m 55.45273s[1]
Declination +10° 31′ 46.2195″[1]
Apparent magnitude (V) 4.00[2]
Characteristics
Spectral type F4 IV[3] + F3 V + K4 V[4]
U−B color index +1.420[5]
B−V color index +0.456[5]
Variable type Suspected[6]
Astrometry
Radial velocity (Rv)−10.3[7] km/s
Proper motion (μ) RA: +141.45[1] mas/yr
Dec.: −79.14[1] mas/yr
Parallax (π)41.26 ± 1.16[1] mas
Distance79 ± 2 ly
(24.2 ± 0.7 pc)
Absolute magnitude (MV)+2.13[8]
Orbit[9]
Primaryι Leo A
Companionι Leo B
Period (P)189.561+0.631
−0.814 yr
Semi-major axis (a)1.926+0.01
−0.009″
Eccentricity (e)0.550±0.003
Inclination (i)127.249+0.287
−0.412°
Longitude of the node (Ω)56.178+0.434
−0.449°
Periastron epoch (T)1948.86+0.193
−0.278
Argument of periastron (ω)
(secondary)		145.345+0.561
−0.714°
Details
ι Leo A
Mass1.417+0.044
−0.081[9] M☉
Radius2.93±0.10[3] R☉
Luminosity11.5[3] L☉
Surface gravity (log g)3.98[10] cgs
Temperature6,739[10] K
Metallicity [Fe/H]0.06[10] dex
Rotational velocity (v sin i)16[3] km/s
Age1.7±0.2[3] Gyr
ι Leo B
Mass1.183+0.163
−0.157[9] M☉
Other designations
ι Leo, 78 Leo, BD+11°2348, GJ 426.1, HD 99028, HIP 55642, HR 4399, SAO 99587[2]
Database references
SIMBADA
B

Iota Leonis, Latinized from ι Leonis, is a quadruple star system[4] in the constellation Leo. The system is fairly close to the Sun, at only 79 light-years (24.2 parsecs) away, based on its parallax.[1] The system has a combined apparent magnitude of 4.00[2] making it faintly visible to the naked eye. It is moving closer to the Sun with a radial velocity of −10 km/s.[7]

The primary star, Iota Leonis A, has a spectral type of F3 IV,[3] matching that of an F-type subgiant star. The second component in the star system is designated Iota Leonis B. It orbits the primary every 190 years, and with its perihelion passage in 1948, the separation between the two is steadily growing.[9] The pair is also listed as a single-lined spectroscopic binary.[11] It is a F-type main-sequence star[4] with a mass 18.3% greater than that of the Sun.[9]

The outer companion is designated StKM 2-732[12] and is also called Iota Leonis C.[13] It has an angular separation from the inner pair by 331" along a position angle of 346°, and is itself a close binary. The combined spectrum is K6V.[4]

Name

In Chinese, 太微右垣 (Tài Wēi Yòu Yuán), meaning Right Wall of Supreme Palace Enclosure, refers to an asterism consisting of ι Leonis, β Virginis, σ Leonis, θ Leonis and δ Leonis.[14] Consequently, the Chinese name for ι Leonis itself is 太微右垣三 (Tài Wēi Zuǒ Yuán sān, English: the Third Star of Right Wall of Supreme Palace Enclosure),[15] representing 西次將 (Xīcìjiāng), meaning The Second Western General.[16] 西次將 (Xīcìjiāng), spelled Tsze Tseang by R.H. Allen, means "the Second General".[17]

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, Floor (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.  Note: see VizieR catalogue I/311.
  2. ↑ 2.0 2.1 2.2 "iot Leo -- Spectroscopic binary". SIMBAD. Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Leo. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Bi, S.-L.; Basu, Sarbani; Li, L.-H. (February 2008). "Seismological Analysis of the Stars γ Serpentis and ι Leonis: Stellar Parameters and Evolution". The Astrophysical Journal 673 (2): 1093–1105. doi:10.1086/521575. Bibcode: 2008ApJ...673.1093B. 
  4. ↑ 4.0 4.1 4.2 4.3 Tokovinin, Andrei (2018-03-01). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series 235 (1): 6. doi:10.3847/1538-4365/aaa1a5. ISSN 0067-0049. Bibcode: 2018ApJS..235....6T.  Iota Leonis' database entry at VizieR.
  5. ↑ 5.0 5.1 Rufener, F. (October 1976). "Second catalogue of stars measured in the Geneva Observatory photometric system". Astronomy & Astrophysics Supplement Series 26: 275–351. Bibcode: 1976A&AS...26..275R. 
  6. ↑ Kukarkin, B. V. (1981). "Nachrichtenblatt der Vereinigung der Sternfreunde e.V. (Catalogue of suspected variable stars)". Nachrichtenblatt der Vereinigung der Sternfreunde (Moscow, Academy of Sciences USSR Shternberg). Bibcode: 1981NVS...C......0K. 
  7. ↑ 7.0 7.1 Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Washington D.C.: Carnegie Institute. Bibcode: 1953GCRV..C......0W. 
  8. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 Anguita-Aguero, Jennifer; Mendez, Rene A.; Videla, Miguel; Costa, Edgardo; Vanzi, Leonardo; Castro-Morales, Nicolas; Caballero-Valdes, Camila (September 2023). "Mass Ratio of Single-line Spectroscopic Binaries with Visual Orbits Using Bayesian Inference and Suitable Priors" (in en). The Astronomical Journal 166 (4): 172. doi:10.3847/1538-3881/acf297. ISSN 1538-3881. Bibcode: 2023AJ....166..172A. 
  10. ↑ 10.0 10.1 10.2 Balachandran, Suchitra (May 1, 1990). "Lithium depletion and rotation in main-sequence stars". Astrophysical Journal, Part 1 354: 310–332. doi:10.1086/168691. Bibcode: 1990ApJ...354..310B. 
  11. ↑ Pourbaix, D. et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics 424 (2): 727–732. doi:10.1051/0004-6361:20041213. Bibcode: 2004A&A...424..727P. 
  12. ↑ "StKM 2-732". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=StKM+2-732. 
  13. ↑ Golovin, Alex; Reffert, Sabine; Just, Andreas; Jordan, Stefan; Vani, Akash; Jahreiß, Hartmut (November 2022). "The Fifth Catalogue of Nearby Stars (CNS5)". Astronomy & Astrophysics 670: A19. doi:10.1051/0004-6361/202244250. Bibcode: 2023A&A...670A..19G.  Catalogue can be accessed here.
  14. ↑ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  15. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
  16. ↑ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name , Hong Kong Space Museum. Accessed on line November 23, 2010.
  17. ↑ Richard Hinckley Allen (1963). "LacusCurtius • Allen's Star Names — Leo". Star Names. https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Leo*.html. 



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