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Delta Eridani

October 21, 2023

Delta Eridani, which is Latinized from δ Eridani, is a star in the equatorial constellation of Eridanus.

δ Eridani
Location of δ Eridani (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Eridanus
Right ascension 03h 43m 14.90088s[1]
Declination –09° 45′ 48.2084″[1]
Apparent magnitude (V) 3.51 - 3.56[2]
Characteristics
Evolutionary stage Subgiant
Spectral type K0 IV[3]
U−B color index +0.69[4]
B−V color index +0.92[4]
Variable type Suspected RS CVn[2]
Astrometry
Radial velocity (Rv)−6.28±0.09[5] km/s
Proper motion (μ) RA: −93.16[1] mas/yr
Dec.: +743.64[1] mas/yr
Parallax (π)110.61 ± 0.29 mas[1]
Distance29.49 ± 0.08 ly
(9.04 ± 0.02 pc)
Absolute magnitude (MV)3.77[6]
Details[7]
Mass1.33±0.07 M☉
Radius2.327±0.029 R☉
Luminosity3.00±0.12 L☉
Surface gravity (log g)3.77±0.08 cgs
Temperature4,986±57 K
Metallicity [Fe/H]+0.15±0.07 dex
Rotational velocity (v sin i)0.7±0.6 km/s
Age6.194[8] Gyr
Other designations
Rana, δ Eridani, 23 Eridani, del Eri, NSV 1246, BD−10°728, GJ 150, HD 23249, HIP 17378, HR 1136, SAO 130686, LHS 1581[9]
Database references
SIMBADdata

The star is visible to the naked eye and has been observed to vary slightly in brightness between magnitudes 3.51 and 3.56,[2] although subsequent observations did not bear this out.[10] It is relatively near to the Sun, with a distance of about 29.5 light years as determined from parallax.[1] The star is drifting closer with a radial velocity of −6 km/s.[5]

Delta Eridani is sometimes called Rana:[11] Rana means "the frog" in Latin, but derivation of this name is uncertain. The name was approved by the International Astronomic Union on 4 April 2022.[12]

Structure Edit

The stellar classification of this star is K0 IV,[3] matching a subgiant star that has exhausted its core hydrogen. This has caused the star to expand and become cooler than a comparable main sequence star. Stellar modelling indicates it is near the end of the subgiant stage and about to transition into a giant. It is an estimated six[8] billion years old with 33% more mass than the Sun. The star has 2.3 times the girth of the Sun and is radiating three times the Sun's luminosity from its photosphere at an effective temperature of 4,986 K.[7]

Delta Eridani is catalogued as a suspected RS Canum Venaticorum variable in 1983,[13] but the activity level for the star is so low that this is considered doubtful. This class of variables occurs in close binary systems. A low projected rotational velocity of under 1 km/s and the lack of radial velocity variation suggests that this putative variable is being viewed from nearly pole-on. However, an examination of the star using interferometry does not detect the presence of a companion at the expected distance.[8]

Chinese name Edit

In Chinese, 天苑 (Tiān Yuàn), meaning Celestial Meadows, refers to an asterism consisting of δ Eridani, γ Eridani, π Eridani, ε Eridani, ζ Eridani, η Eridani, π Ceti, τ1 Eridani, τ2 Eridani, τ3 Eridani, τ4 Eridani, τ5 Eridani, τ6 Eridani, τ7 Eridani, τ8 Eridani and τ9 Eridani.[14] Consequently, the Chinese name for δ Eridani itself is 天苑三 (Tiān Yuàn sān, English: the Third Star of Celestial Meadows.)[15]

See also Edit

References Edit

  1. ^ a b c d e f van Leeuwen, F. (2007). "HIP 17378". Hipparcos, the New Reduction. Retrieved 2009-12-11.
  2. ^ a b c Samus', N. N; et al. (2017). "General catalogue of variable stars". Astronomy Reports. GCVS 5.1. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  3. ^ a b Spinrad, Hyron; Taylor, Benjamin J. (1969). "Scanner Abundance Studies. I. an Investigation of Supermetallicity in Late-Type Evolved Stars". Astrophysical Journal. 157: 1279. Bibcode:1969ApJ...157.1279S. doi:10.1086/150154.
  4. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  5. ^ a b Jofré, E.; et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931.
  6. ^ Pizzolato, N.; et al. (September 2000). "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases". Astronomy and Astrophysics. 361: 614–628. Bibcode:2000A&A...361..614P.
  7. ^ a b Bruntt, H.; et al. (July 2010). "Accurate fundamental parameters for 23 bright solar-type stars". Monthly Notices of the Royal Astronomical Society. 405 (3): 1907–1923. arXiv:1002.4268. Bibcode:2010MNRAS.405.1907B. doi:10.1111/j.1365-2966.2010.16575.x. S2CID 118495267.
  8. ^ a b c Thévenin, F.; et al. (June 2005). "VLTI/VINCI diameter constraints on the evolutionary status of δ Eri, ξ Hya, η Boo". Astronomy and Astrophysics. 436 (1): 253–262. arXiv:astro-ph/0501420. Bibcode:2005A&A...436..253T. doi:10.1051/0004-6361:20042075. S2CID 118169489.
  9. ^ "Del Eri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-11.
  10. ^ Eaton, J. A.; Poe, C. H. (April 1985). "Limits on the Variability of epsilon Eridani and delta Eridani". Information Bulletin on Variable Stars. 2712: 1. Bibcode:1985IBVS.2712....1E.
  11. ^ Bečvář, A. (1951). Atlas Coeli Skalnaté Pleso II - Katalog 1950.0. Přírodovědecké Vydavatelstrí. p. 277. Retrieved 27 May 2019.
  12. ^ "Naming Stars".
  13. ^ Fisher, G. F.; et al. (January 1983). "Delta Eridani: a Very Bright New Variable Star". Information Bulletin on Variable Stars. 2259: 1. Bibcode:1983IBVS.2259....1F.
  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 January 30, 2011, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.

External links Edit

  • Kaler, James B. "RANA (Delta Eridani)". STARS. Retrieved 2021-01-11.
  • "Rana". SolStation Company. Retrieved 2021-01-11.

October 21, 2023
delta, eridani, which, latinized, from, eridani, star, equatorial, constellation, eridanus, eridanilocation, eridani, circled, observation, dataepoch, j2000, equinox, j2000constellation, eridanusright, ascension, 90088s, declination, 2084, apparent, magnitude,. Delta Eridani which is Latinized from d Eridani is a star in the equatorial constellation of Eridanus d EridaniLocation of d Eridani circled Observation dataEpoch J2000 Equinox J2000Constellation EridanusRight ascension 03h 43m 14 90088s 1 Declination 09 45 48 2084 1 Apparent magnitude V 3 51 3 56 2 CharacteristicsEvolutionary stage SubgiantSpectral type K0 IV 3 U B color index 0 69 4 B V color index 0 92 4 Variable type Suspected RS CVn 2 AstrometryRadial velocity Rv 6 28 0 09 5 km sProper motion m RA 93 16 1 mas yr Dec 743 64 1 mas yrParallax p 110 61 0 29 mas 1 Distance29 49 0 08 ly 9 04 0 02 pc Absolute magnitude MV 3 77 6 Details 7 Mass1 33 0 07 M Radius2 327 0 029 R Luminosity3 00 0 12 L Surface gravity log g 3 77 0 08 cgsTemperature4 986 57 KMetallicity Fe H 0 15 0 07 dexRotational velocity v sin i 0 7 0 6 km sAge6 194 8 GyrOther designationsRana d Eridani 23 Eridani del Eri NSV 1246 BD 10 728 GJ 150 HD 23249 HIP 17378 HR 1136 SAO 130686 LHS 1581 9 Database referencesSIMBADdataThe star is visible to the naked eye and has been observed to vary slightly in brightness between magnitudes 3 51 and 3 56 2 although subsequent observations did not bear this out 10 It is relatively near to the Sun with a distance of about 29 5 light years as determined from parallax 1 The star is drifting closer with a radial velocity of 6 km s 5 Delta Eridani is sometimes called Rana 11 Rana means the frog in Latin but derivation of this name is uncertain The name was approved by the International Astronomic Union on 4 April 2022 12 Contents 1 Structure 2 Chinese name 3 See also 4 References 5 External linksStructure EditThe stellar classification of this star is K0 IV 3 matching a subgiant star that has exhausted its core hydrogen This has caused the star to expand and become cooler than a comparable main sequence star Stellar modelling indicates it is near the end of the subgiant stage and about to transition into a giant It is an estimated six 8 billion years old with 33 more mass than the Sun The star has 2 3 times the girth of the Sun and is radiating three times the Sun s luminosity from its photosphere at an effective temperature of 4 986 K 7 Delta Eridani is catalogued as a suspected RS Canum Venaticorum variable in 1983 13 but the activity level for the star is so low that this is considered doubtful This class of variables occurs in close binary systems A low projected rotational velocity of under 1 km s and the lack of radial velocity variation suggests that this putative variable is being viewed from nearly pole on However an examination of the star using interferometry does not detect the presence of a companion at the expected distance 8 Chinese name EditIn Chinese 天苑 Tian Yuan meaning Celestial Meadows refers to an asterism consisting of d Eridani g Eridani p Eridani e Eridani z Eridani h Eridani p Ceti t1 Eridani t2 Eridani t3 Eridani t4 Eridani t5 Eridani t6 Eridani t7 Eridani t8 Eridani and t9 Eridani 14 Consequently the Chinese name for d Eridani itself is 天苑三 Tian Yuan san English the Third Star of Celestial Meadows 15 See also EditList of star systems within 25 30 light yearsReferences Edit a b c d e f van Leeuwen F 2007 HIP 17378 Hipparcos the New Reduction Retrieved 2009 12 11 a b c Samus N N et al 2017 General catalogue of variable stars Astronomy Reports GCVS 5 1 61 1 80 Bibcode 2017ARep 61 80S doi 10 1134 S1063772917010085 S2CID 125853869 a b Spinrad Hyron Taylor Benjamin J 1969 Scanner Abundance Studies I an Investigation of Supermetallicity in Late Type Evolved Stars Astrophysical Journal 157 1279 Bibcode 1969ApJ 157 1279S doi 10 1086 150154 a b Mermilliod J C 1986 Compilation of Eggen s UBV data transformed to UBV unpublished Catalogue of Eggen s UBV Data Bibcode 1986EgUBV 0M a b Jofre E et al 2015 Stellar parameters and chemical abundances of 223 evolved stars with and without planets Astronomy amp Astrophysics 574 A50 arXiv 1410 6422 Bibcode 2015A amp A 574A 50J doi 10 1051 0004 6361 201424474 S2CID 53666931 Pizzolato N et al September 2000 Evolution of X ray activity of 1 3 Msun late type stars in early post main sequence phases Astronomy and Astrophysics 361 614 628 Bibcode 2000A amp A 361 614P a b Bruntt H et al July 2010 Accurate fundamental parameters for 23 bright solar type stars Monthly Notices of the Royal Astronomical Society 405 3 1907 1923 arXiv 1002 4268 Bibcode 2010MNRAS 405 1907B doi 10 1111 j 1365 2966 2010 16575 x S2CID 118495267 a b c Thevenin F et al June 2005 VLTI VINCI diameter constraints on the evolutionary status of d Eri 3 Hya h Boo Astronomy and Astrophysics 436 1 253 262 arXiv astro ph 0501420 Bibcode 2005A amp A 436 253T doi 10 1051 0004 6361 20042075 S2CID 118169489 Del Eri SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 2021 01 11 Eaton J A Poe C H April 1985 Limits on the Variability of epsilon Eridani and delta Eridani Information Bulletin on Variable Stars 2712 1 Bibcode 1985IBVS 2712 1E Becvar A 1951 Atlas Coeli Skalnate Pleso II Katalog 1950 0 Prirodovedecke Vydavatelstri p 277 Retrieved 27 May 2019 Naming Stars Fisher G F et al January 1983 Delta Eridani a Very Bright New Variable Star Information Bulletin on Variable Stars 2259 1 Bibcode 1983IBVS 2259 1F 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 香港太空館 研究資源 亮星中英對照表 Archived January 30 2011 at the Wayback Machine Hong Kong Space Museum Accessed on line November 23 2010 External links EditKaler James B RANA Delta Eridani STARS Retrieved 2021 01 11 Rana SolStation Company Retrieved 2021 01 11 nStars entry Retrieved from https en wikipedia org w index php title Delta Eridani amp oldid 1170209323, wikipedia, wiki, book, books, library,

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