Star in the constellation Eridanus
δ Eridani / Rana Location of δ Eridani (circled)
Observation dataEpoch J2000 Equinox J2000 Constellation Eridanus Right ascension 03h 43m 14.90054s [ 1] Declination −09° 45′ 48.2110″[ 1] Apparent magnitude (V)3.53[ 2] Characteristics Evolutionary stage Subgiant Spectral type K0 IV[ 3] U−Bcolor index +0.69[ 4] B−Vcolor index +0.92[ 4] Variable type none[ 2] Astrometry Radial velocity (Rv )± 0.09[ 5] km/s Proper motion (μ)RA: −93.634mas /yr [ 1] Dec.: +744.360mas /yr [ 1] Parallax (π)110.0254± 0.1944 mas [ 1] Distance 29.64 ± 0.05 ly pc ) Absolute magnitude (MV )3.77[ 6] Details[ 7] Mass ± 0.07[ 8] M ☉ Radius ± 0.01R ☉ Luminosity ± 0.09L ☉ Surface gravity (log g )± 0.1cgs Temperature ± 48K Metallicity ± 0.03dex Rotational velocity (v sin i )± 0.6[ 8] Age 6.194[ 9] Gyr Other designations Rana,δ Eri ,23 Eridani ,NSV 1246BD −10°728GJ 150HD 23249HIP 17378HR 1136SAO 130686LHS 1581[ 10] Database references SIMBAD data
Delta Eridani ,Latinized from δ Eridani, also namedRana , is the fifth-brighteststar in theconstellation ofEridanus .
The star is visible to the naked eye with anapparent magnitude of 3.54. It is relatively near to theSun , with a distance of about 29.6 light-years as determined fromparallax .[ 1] radial velocity of −6 km/s.[ 5]
Delta Eridani is sometimes called Rana:[ 11] Rana frog " inLatin , but derivation of this name is uncertain. The name was approved by theInternational Astronomical Union on 4 April 2022.[ 12]
InChinese ,天苑 Tiān Yuàn Celestial Meadows 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 andτ9 Eridani .[ 13] Chinese name for δ Eridani itself is天苑三 Tiān Yuàn sān the Third Star of Celestial Meadows .)[ 14]
Thestellar classification of this star is K0 IV,[ 3] subgiant star that has exhausted its corehydrogen . This has caused the star to expand and become cooler than a comparablemain sequence star. Stellar modelling indicates it is near the end of thesubgiant stage and about to transition into agiant . It is an estimated six billion years old[ 9] mass than the Sun .[ 8] size of the Sun and is radiating three times theSun's luminosity from itsphotosphere at aneffective temperature of 5,022 K.[ 7]
Delta Eridani was catalogued as a suspectedRS Canum Venaticorum variable in 1983,[ 15] [ 16] [ 17] interferometry did not detect the presence of a companion at the expected distance.[ 9] [ 18] chromospheric activity .[ 18] projected rotational velocity of under 1 km/s and the lack of radial velocity variation suggest that this star is being viewed from nearly pole-on.[ 9]
^a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023)."Gaia Data Release 3. Summary of the content and survey properties" .Astronomy and Astrophysics .674 : A1.arXiv :2208.00211 Bibcode :2023A&A...674A...1G .doi :10.1051/0004-6361/202243940 S2CID 244398875 . Gaia DR3 record for this source atVizieR .^a b "del Eri" .International Variable Star Index . Retrieved2025-02-24 .^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 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 . ^ 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 . ^a b Rains, Adam D.; et al. (April 2020)."Precision angular diameters for 16 southern stars with VLTI/PIONIER" .Monthly Notices of the Royal Astronomical Society .493 (2):2377– 2394.arXiv :2004.02343 Bibcode :2020MNRAS.493.2377R .doi :10.1093/mnras/staa282 ^a b c 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 d 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 . ^ "Del Eri" .SIMBAD Centre de données astronomiques de Strasbourg . Retrieved2021-01-11 .^ Bečvář, A. (1951).Atlas Coeli Skalnaté Pleso II - Katalog 1950.0 . Retrieved27 May 2019 .^ "Naming Stars" .^ (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 theWayback Machine , Hong Kong Space Museum. Accessed on line November 23, 2010.^ Kholopov, P. N.; Samus', N. N.; Kazarovets, E. V.; Kireeva, N. N. (1987). "The 68th Name-List of Variable Stars".Information Bulletin on Variable Stars .3058 : 1.Bibcode :1987IBVS.3058....1K . ^ 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 . ^ 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 . ^a b Laliotis, Katherine; Burt, Jennifer A.; Mamajek, Eric E.; Li, Zhexing; Perdelwitz, Volker; Zhao, Jinglin; Butler, R. Paul; Holden, Bradford; Rosenthal, Lee; Fulton, B. J.; Feng, Fabo; Kane, Stephen R.; Bailey, Jeremy; Carter, Brad; Crane, Jeffrey D.; Furlan, Elise; Gnilka, Crystal L.; Howell, Steve B.; Laughlin, Gregory; Shectman, Stephen A.; Teske, Johanna K.; Tinney, C. G.; Vogt, Steven S.; Wang, Sharon Xuesong; Wittenmyer, Robert A. (2023-04-01)."Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions*" .The Astronomical Journal .165 (4): 176.arXiv :2302.10310 Bibcode :2023AJ....165..176L .doi :10.3847/1538-3881/acc067 ISSN 0004-6256 .
