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Lambda Aquarii

October 27, 2023

Lambda Aquarii, informally known as Hydor (/ˈhaɪdɔːr/),[11][12] is a variable star in the equatorial constellation of Aquarius. The name is Latinized from the Bayer designation λ Aquarii. The apparent visual magnitude of this star ranges from 3.57 down to 3.80,[3] which is bright enough to be visible with the naked eye. It lies just 0.39 degrees south of the ecliptic[13] and so is subject to lunar occultations.[14][15] The star is eclipsed by the sun from about 1-4 March;[16] thus the star can be viewed the whole night, crossing the sky, in early September, in the current epoch. Lambda Aquarii is located at a distance of approximately 310 light-years (95 pc) from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −10.5 km/s.[6]

Lambda Aquarii
Location of λ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
Right ascension 22h 52m 36.87723s[1]
Declination −07° 34′ 46.5830″[1]
Apparent magnitude (V) 3.722[2] (3.57 to 3.80)[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type M2.5 IIIa Fe–1[5]
U−B color index +1.721[2]
B−V color index +1.641[2]
Variable type Lb[3]
Astrometry
Radial velocity (Rv)−10.46±0.53[6] km/s
Proper motion (μ) RA: +11.806[1] mas/yr
Dec.: +34.967[1] mas/yr
Parallax (π)8.9360 ± 0.2356 mas[7]
Distance365 ± 10 ly
(112 ± 3 pc)
Absolute magnitude (MV)−1.5[8]
Details
Mass3.6[9] M☉
Radius44.10+21.14
−13.20[1] R☉
Luminosity698.5±41.5[1] L☉
Temperature3,835[9] K
Metallicity [Fe/H]−2.25[8] dex
Other designations
λ Aqr, 73 Aquarii, BD–08°968, FK5 864, HD 216386, HIP 112961, HR 8698, SAO 146362[10]
Database references
SIMBADdata
A visual band light curve for Lambda Aquarii, plotted from data published by Tabur et al. (2009).[17] The inset plot shows the same data folded with a period of 24.5 days, after a linear trend had been removed.

The stellar classification of Lambda Aquarii is M2.5 IIIa Fe–1,[5] indicating this is an aging red giant star with an underabundance of iron showing in its spectrum. This star is on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen.[4] With 3.6[9] times the mass of the Sun, it has expanded to 44[1] times the Sun's radius. It is classified as slow irregular variable and pulsation periods of 24.5, 32.0, and 49.5 days have been identified.[17] On average, it is radiating nearly 700[1] times the luminosity of the Sun from the photosphere at an effective temperature of 3,835 K.[9]

Naming edit

Hydor is from Greek Ὕδωρ "water", a name given by Proclus, according to Richard Hinckley Allen. Another Greek name for the star is Ekkhysis, from εκχυσις "outpouring".[12]

In Chinese, 壘壁陣 (Lěi Bì Zhèn), meaning Line of Ramparts, refers to an asterism consisting of λ Aquarii, κ Capricorni, ε Capricorni, γ Capricorni, δ Capricorni, ι Aquarii, σ Aquarii, φ Aquarii, 27 Piscium, 29 Piscium, 33 Piscium and 30 Piscium.[18] Consequently, λ Aquarii itself is 壘壁陣七 (Lěi Bì Zhèn qī, English: the Seventh Star of Line of Ramparts.)[19]

References edit

  1. ^ a b c d e f g h i Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c Gutierrez-Moreno, Adelina; et al. (1966). "A System of photometric standards". Publ. Dept. Astron. Univ. Chile. Publicaciones Universidad de Chile, Department de Astronomy. 1: 1–17. Bibcode:1966PDAUC...1....1G.
  3. ^ a b c Samus, N. N.; Kazarovets, E. V.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports (5.1 ed.). 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869. Retrieved 2019-11-23.
  4. ^ a b Lebzelter, T.; Hron, J. (January 2008). "BRITE stars on the AGB". Communications in Asteroseismology. 152: 178–181. Bibcode:2008CoAst.152..178L. doi:10.1553/cia152s178.
  5. ^ a b 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  6. ^ a b Famaey, B.; et al. (May 2009). "Spectroscopic binaries among Hipparcos M giants. I. Data, orbits, and intrinsic variations". Astronomy and Astrophysics. 498 (2): 627–640. arXiv:0901.0934. Bibcode:2009A&A...498..627F. doi:10.1051/0004-6361/200810698. S2CID 18739721.
  7. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  8. ^ a b Dupree, A. K.; Li, Timothy Q.; Smith, Graeme H. (October 2007). "Hubble Space Telescope Observations of Chromospheres in Metal-Deficient Field Giants". The Astronomical Journal. 134 (4): 1348–1359. arXiv:0709.1709. Bibcode:2007AJ....134.1348D. doi:10.1086/520925. S2CID 14481140.
  9. ^ a b c d Tsuji, Takashi (May 2007). Kupka, F.; Roxburgh, I.; Chan, K. (eds.). "Convection in Astrophysics, Proceedings of IAU Symposium #239 held 21-25 August, 2006 in Prague, Czech Republic". Proceedings of the International Astronomical Union. 2: 307–310. arXiv:astro-ph/0610180. Bibcode:2007IAUS..239..307T. doi:10.1017/S1743921307000622. S2CID 119362842. Isotopic abundances of Carbon and Oxygen in Oxygen-rich giant stars.
  10. ^ "* lam Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-01.
  11. ^ Kaler, James B. "Hydor". STARS. Retrieved 2017-08-17.
  12. ^ a b Allen, Richard Hinckey. "Star Names: Their Lore and Meaning". Retrieved 2017-08-17.
  13. ^ John Pratt's stars re-publication by Dr J.P. Pratt (Doctor of Astronomy, University of Arizona) of sidereal coordinate data. Note: possibly a non-book published source.
  14. ^ Schmidtke, P. C.; Africano, J. L. (January 2011). "KPNO Lunar Occultation Summary. III". The Astronomical Journal. 141 (1): 7. Bibcode:2011AJ....141...10S. doi:10.1088/0004-6256/141/1/10. S2CID 120313180. 10.
  15. ^ Nather, R. Edward; et al. (June 1970). "The Angular Diameter of Lambda Aquarii". Astrophysical Journal. 160: L181. Bibcode:1970ApJ...160L.181N. doi:10.1086/180555.
  16. ^ Ford, Dominic. "In-The-Sky.org Planetarium". Retrieved 2021-06-07.
  17. ^ a b Tabur, V.; et al. (December 2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–1961. arXiv:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. S2CID 15358380.
  18. ^ (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.
  19. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日

External links edit

  • Image Lambda Aquarii

October 27, 2023
lambda, aquarii, informally, known, hydor, ɔːr, variable, star, equatorial, constellation, aquarius, name, latinized, from, bayer, designation, aquarii, apparent, visual, magnitude, this, star, ranges, from, down, which, bright, enough, visible, with, naked, l. Lambda Aquarii informally known as Hydor ˈ h aɪ d ɔːr 11 12 is a variable star in the equatorial constellation of Aquarius The name is Latinized from the Bayer designation l Aquarii The apparent visual magnitude of this star ranges from 3 57 down to 3 80 3 which is bright enough to be visible with the naked eye It lies just 0 39 degrees south of the ecliptic 13 and so is subject to lunar occultations 14 15 The star is eclipsed by the sun from about 1 4 March 16 thus the star can be viewed the whole night crossing the sky in early September in the current epoch Lambda Aquarii is located at a distance of approximately 310 light years 95 pc from the Sun based on parallax 1 but is drifting closer with a radial velocity of 10 5 km s 6 Lambda AquariiLocation of l Aquarii circled Observation dataEpoch J2000 Equinox J2000Constellation AquariusRight ascension 22h 52m 36 87723s 1 Declination 07 34 46 5830 1 Apparent magnitude V 3 722 2 3 57 to 3 80 3 CharacteristicsEvolutionary stage AGB 4 Spectral type M2 5 IIIa Fe 1 5 U B color index 1 721 2 B V color index 1 641 2 Variable type Lb 3 AstrometryRadial velocity Rv 10 46 0 53 6 km sProper motion m RA 11 806 1 mas yr Dec 34 967 1 mas yrParallax p 8 9360 0 2356 mas 7 Distance365 10 ly 112 3 pc Absolute magnitude MV 1 5 8 DetailsMass3 6 9 M Radius44 10 21 14 13 20 1 R Luminosity698 5 41 5 1 L Temperature3 835 9 KMetallicity Fe H 2 25 8 dexOther designationsl Aqr 73 Aquarii BD 08 968 FK5 864 HD 216386 HIP 112961 HR 8698 SAO 146362 10 Database referencesSIMBADdata A visual band light curve for Lambda Aquarii plotted from data published by Tabur et al 2009 17 The inset plot shows the same data folded with a period of 24 5 days after a linear trend had been removed The stellar classification of Lambda Aquarii is M2 5 IIIa Fe 1 5 indicating this is an aging red giant star with an underabundance of iron showing in its spectrum This star is on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen 4 With 3 6 9 times the mass of the Sun it has expanded to 44 1 times the Sun s radius It is classified as slow irregular variable and pulsation periods of 24 5 32 0 and 49 5 days have been identified 17 On average it is radiating nearly 700 1 times the luminosity of the Sun from the photosphere at an effective temperature of 3 835 K 9 Naming editHydor is from Greek Ὕdwr water a name given by Proclus according to Richard Hinckley Allen Another Greek name for the star is Ekkhysis from ekxysis outpouring 12 In Chinese 壘壁陣 Lei Bi Zhen meaning Line of Ramparts refers to an asterism consisting of l Aquarii k Capricorni e Capricorni g Capricorni d Capricorni i Aquarii s Aquarii f Aquarii 27 Piscium 29 Piscium 33 Piscium and 30 Piscium 18 Consequently l Aquarii itself is 壘壁陣七 Lei Bi Zhen qi English the Seventh Star of Line of Ramparts 19 References edit a b c d e f g h i Brown A G A et al Gaia collaboration August 2018 Gaia Data Release 2 Summary of the contents and survey properties Astronomy amp Astrophysics 616 A1 arXiv 1804 09365 Bibcode 2018A amp A 616A 1G doi 10 1051 0004 6361 201833051 Gaia DR2 record for this source at VizieR a b c Gutierrez Moreno Adelina et al 1966 A System of photometric standards Publ Dept Astron Univ Chile Publicaciones Universidad de Chile Department de Astronomy 1 1 17 Bibcode 1966PDAUC 1 1G a b c Samus N N Kazarovets E V et al 2017 General Catalogue of Variable Stars Astronomy Reports 5 1 ed 61 1 80 88 Bibcode 2017ARep 61 80S doi 10 1134 S1063772917010085 S2CID 125853869 Retrieved 2019 11 23 a b Lebzelter T Hron J January 2008 BRITE stars on the AGB Communications in Asteroseismology 152 178 181 Bibcode 2008CoAst 152 178L doi 10 1553 cia152s178 a b 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 arXiv 0806 2878 Bibcode 2008MNRAS 389 869E doi 10 1111 j 1365 2966 2008 13596 x S2CID 14878976 a b Famaey B et al May 2009 Spectroscopic binaries among Hipparcos M giants I Data orbits and intrinsic variations Astronomy and Astrophysics 498 2 627 640 arXiv 0901 0934 Bibcode 2009A amp A 498 627F doi 10 1051 0004 6361 200810698 S2CID 18739721 Brown A G A et al Gaia collaboration 2021 Gaia Early Data Release 3 Summary of the contents and survey properties Astronomy amp Astrophysics 649 A1 arXiv 2012 01533 Bibcode 2021A amp A 649A 1G doi 10 1051 0004 6361 202039657 S2CID 227254300 Erratum doi 10 1051 0004 6361 202039657e Gaia EDR3 record for this source at VizieR a b Dupree A K Li Timothy Q Smith Graeme H October 2007 Hubble Space Telescope Observations of Chromospheres in Metal Deficient Field Giants The Astronomical Journal 134 4 1348 1359 arXiv 0709 1709 Bibcode 2007AJ 134 1348D doi 10 1086 520925 S2CID 14481140 a b c d Tsuji Takashi May 2007 Kupka F Roxburgh I Chan K eds Convection in Astrophysics Proceedings of IAU Symposium 239 held 21 25 August 2006 in Prague Czech Republic Proceedings of the International Astronomical Union 2 307 310 arXiv astro ph 0610180 Bibcode 2007IAUS 239 307T doi 10 1017 S1743921307000622 S2CID 119362842 Isotopic abundances of Carbon and Oxygen in Oxygen rich giant stars lam Aqr SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2012 07 01 Kaler James B Hydor STARS Retrieved 2017 08 17 a b Allen Richard Hinckey Star Names Their Lore and Meaning Retrieved 2017 08 17 John Pratt s stars re publication by Dr J P Pratt Doctor of Astronomy University of Arizona of sidereal coordinate data Note possibly a non book published source Schmidtke P C Africano J L January 2011 KPNO Lunar Occultation Summary III The Astronomical Journal 141 1 7 Bibcode 2011AJ 141 10S doi 10 1088 0004 6256 141 1 10 S2CID 120313180 10 Nather R Edward et al June 1970 The Angular Diameter of Lambda Aquarii Astrophysical Journal 160 L181 Bibcode 1970ApJ 160L 181N doi 10 1086 180555 Ford Dominic In The Sky org Planetarium Retrieved 2021 06 07 a b Tabur V et al December 2009 Long term photometry and periods for 261 nearby pulsating M giants Monthly Notices of the Royal Astronomical Society 400 4 1945 1961 arXiv 0908 3228 Bibcode 2009MNRAS 400 1945T doi 10 1111 j 1365 2966 2009 15588 x S2CID 15358380 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 in Chinese AEEA Activities of Exhibition and Education in Astronomy 天文教育資訊網 2006 年 7 月 7 日External links editImage Lambda Aquarii Named Stars Retrieved from https en wikipedia org w index php title Lambda Aquarii amp oldid 1175038326, wikipedia, wiki, book, books, library,

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