Delta Leporis

Delta Leporis (δ Leporis) is a solitary,[11] orange-hued star in the southern constellation of Lepus. It is visible to the naked eye with an apparent visual magnitude of 3.85.[2] Based upon an annual parallax shift of 28.68 mas,[1] it is 114 light years distant from Earth.

Delta Leporis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lepus
Right ascension  05h 51m 19.29613s[1]
Declination −20° 52′ 44.7232″[1]
Apparent magnitude (V) 3.85[2]
Characteristics
Spectral type K1 IV Fe−0.5[3] or K0 IIIb Fe−1.5 CH0.5[4]
U−B color index +0.71[2]
B−V color index +0.98[2]
Astrometry
Radial velocity (Rv)+100.20[5] km/s
Proper motion (μ) RA: +229.49[1] mas/yr
Dec.: −648.41[1] mas/yr
Parallax (π)28.68 ± 0.17[1] mas
Distance113.7 ± 0.7 ly
(34.9 ± 0.2 pc)
Absolute magnitude (MV)+1.04[6]
Details
Mass0.94[6] M☉
Radius10[7] R☉
Luminosity45.7[6] L☉
Surface gravity (log g)2.46±0.23[8] cgs
Temperature4,660±84[8] K
Metallicity [Fe/H]−0.74±0.09[8] dex
Rotational velocity (v sin i)0[9] km/s
Age10.7[6] Gyr
Other designations
 Lep, 15 Lep, BD−20° 1211, FK5 222, GC 7362, HD 39364, HIP 27654, HR 2035, SAO 170926, LHS 1792[10]
Database references
SIMBADdata

This is an old, evolved K-type star with an age of about 10.7 billion years.[6] Keenan and McNeil (1989) classified it as K0 IIIb Fe−1.5 CH0.5,[4] indicating it is a giant star showing a deficiency of iron and an excess of cyanogen in its atmosphere. However, Gray et al. (2006) listed it as K1 IV Fe−0.5,[3] which would suggest a less evolved subgiant star. It may be a red clump star, which indicates it is generating energy through helium fusion at its core.[12]

The measured angular diameter of this star, after correction for limb darkening, is 2.63±0.04 mas.[13] At the estimated distance of this star, this yields a physical size of about 10 times the radius of the Sun.[7] It has only 94%[6] of the Sun's mass and is radiating 46[6] times the Sun's luminosity from its photosphere at an effective temperature of 4,660 K.[8]

References
  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  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. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  4. Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  5. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
  6. Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781.
  7. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  8. Sharma, Kaushal; et al. (2016), "New atmospheric parameters and spectral interpolator for the MILES cool stars", Astronomy & Astrophysics, 585: 27, arXiv:1512.04882, Bibcode:2016A&A...585A..64S, doi:10.1051/0004-6361/201526111, A64.
  9. Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory, University of Kyoto, Bibcode:1970crvs.book.....U.
  10. "del Lep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-18.
  11. 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.
  12. Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278.
  13. Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
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