Delta Eridani

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Delta Eridani
Observation data
Epoch J2000      Equinox J2000
Constellation Eridanus
Right ascension 03h 43m 14.90s[1]
Declination –09° 45′ 48.2″[1]
Apparent magnitude (V) 3.54[2]
Characteristics
Spectral type K0 IV[3]
U−B color index +0.69[4]
B−V color index +0.92[4]
Variable type Suspected[citation needed]
Astrometry
Radial velocity (Rv) –6.28 ± 0.09[5] km/s
Proper motion (μ) RA: –93.16 ± 0.29[1] mas/yr
Dec.: +743.64 ± 0.22[1] mas/yr
Parallax (π) 110.61 ± 0.29[1] mas
Distance 29.49 ± 0.08 ly
(9.04 ± 0.02 pc)
Absolute magnitude (MV) 3.77[6]
Details
Mass 1.33 ± 0.07[7] M
Radius 2.327 ± 0.029[7] R
Luminosity 3.00 ± 0.12[7] L
Surface gravity (log g) 3.9[8] cgs
Temperature 5,055[9] K
Metallicity [Fe/H] 0.13[9] dex
Rotational velocity (v sin i) 1.0[6] km/s
Other designations
δ Eridani, 23 Eridani, HD 23249, HR 1136, BD−10° 728, GCTP 788, GJ 150, LHS 1581, HIP 17378.
Database references
SIMBAD data

Delta Eridani (δ Eri, δ Eridani) is a 3.54 magnitude star in the constellation of Eridanus. It is also called Rana. The name Rana means "the frog" in Latin. Rana was referenced as a guide star in "Sky Captain and the World of Tomorrow"[10]

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.[11] Consequently, δ Eridani itself is known as 天苑三 (Tiān Yuàn sān, English: the Third Star of Celestial Meadows.)[12]

Structure[edit]

This star is relatively near to the Sun, at a measured distance of about 29 light years. It is sometime listed as a RS Canum Venaticorum-type variable star, but this is likely to be an error. (It is currently a suspected variable.) Rana is a sub-giant star that is near the end of its hydrogen-burning cycle and is now consuming helium. This has caused the star to expand and become hotter than a comparable main sequence star. As a sub-giant star it is subject to pulsations in its atmosphere.

Radial velocity surveys of this star have thus far failed to discern any gas giants in orbit.

See also[edit]

References[edit]

  1. ^ a b c d e van Leeuwen, F. (2007). "HIP 17378". Hipparcos, the New Reduction. Retrieved 2009-12-11. 
  2. ^ 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. Bibcode:2002yCat.2237....0D. 
  3. ^ 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)". Bibcode:1986EgUBV........0M. 
  5. ^ Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; de la Villarmois, E. Artur; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574. arXiv:1410.6422Freely accessible. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. 
  6. ^ a b Pizzolato, N.; Maggio, A.; Sciortino, S. (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 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:1002.4268Freely accessible, Bibcode:2010MNRAS.405.1907B, doi:10.1111/j.1365-2966.2010.16575.x 
  8. ^ Morell, O.; Kallander, D.; Butcher, H. R (1999). "The age of the Galaxy from thorium in G dwarfs, a re-analysis". Astronomy and Astrophysics. 259 (2): 543–548. Bibcode:1992A&A...259..543M. 
  9. ^ a b Piau, L.; et al. (February 2011), "Surface convection and red-giant radius measurements", Astronomy and Astrophysics, 526: A100, arXiv:1010.3649Freely accessible, Bibcode:2011A&A...526A.100P, doi:10.1051/0004-6361/201014442 
  10. ^ Constellations of Words - Eridanus (Rana)
  11. ^ (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.
  12. ^ (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.

Sources[edit]

  • Fisher, G. F., Hall, D. S., Henry, G. W., Landis, H. J., Renner, T. R., and Shore, S. N., "Delta Eridani: A Very Bright New Variable Star,", Information Bulletin on Variable Stars, No. 2259, 1983.
  • Eaton, J. A.; Poe, C. H., "Limits on the Variability of epsilon Eridani and delta Eridani", Information Bulletin on Variable Stars, 2712, 1985.

External links[edit]