Epsilon Leporis
| |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lepus |
| Right ascension | 05h 05m 27.66537s[1] |
| Declination | –22° 22′ 15.7239″[1] |
| Apparent magnitude (V) | +3.166[2] |
| Characteristics | |
| Spectral type | K4 III[3] |
| U−B color index | +1.783[2] |
| B−V color index | +1.478[2] |
| Astrometry | |
| Radial velocity (Rv) | +1.0[4] km/s |
| Proper motion (μ) | RA: +21.13[1] mas/yr Dec.: –73.11[1] mas/yr |
| Parallax (π) | 15.29 ± 0.19[1] mas |
| Distance | 213 ± 3 ly (65.4 ± 0.8 pc) |
| Absolute magnitude (MV) | –1.02 ± 0.10[5] |
| Details | |
| Mass | 1.70 ± 0.19[5] M☉ |
| Radius | 40.1 ± 3.2[5] R☉ |
| Luminosity | 372[6] L☉ |
| Surface gravity (log g) | 1.43 ± 0.09[5] cgs |
| Temperature | 4,131[5] K |
| Metallicity [Fe/H] | –0.02[5] dex |
| Age | 1.72 ± 0.47[5] Gyr |
| Other designations | |
Epsilon Leporis (ε Lep, ε Lep) is a third-magnitude star in the southern constellation Lepus. The apparent visual magnitude of +3.166[2] places it third in brightness among the stars in this constellation. Based upon parallax measurements, it is located at a distance of around 213 light-years (65 parsecs) from Earth.[1]
This is an evolved giant star with a stellar classification of K4 III[3] that has expanded to 40 times the Sun's radius. It is about 1.72 billion years old and has 1.70 times the mass of the Sun, with a luminosity 372[6] times as great. The outer atmosphere is cooler than the Sun's with an effective temperature of 4,131 K,[5] giving it the orange hue of a K-type star.[8] In terms of its composition, this star shows a similar abundance of elements other than hydrogen and helium to the Sun.[5]
The envelope of this star is undergoing oscillations that show up as changes in the star's radial velocity. Over long durations these follow a linear trend, in combination with shorter period oscillations occurring over a few days. These oscillations are unlikely to be the result of rotational module as that would imply a high rotation rate, which would display itself through strong X-ray emissions. Instead, they may be the result of solar-like and Mira-like oscillations.[9]
References
- 1 2 3 4 5 6 van Leeuwen, F. (November 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.
- 1 2 3 4 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.
- 1 2 Houk, Nancy; Smith-Moore, M. (1978), "Michigan catalogue of two-dimensional spectral types for the HD stars", Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4 (Ann Arbor: Dept. of Astronomy, University of Michigan) 4, Bibcode:1988MSS...C04....0H
- ↑ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb (Astronomisches Rechen-Institut Heidelberg) 35 (35): 1, Bibcode:1999VeARI..35....1W
- 1 2 3 4 5 6 7 8 9 da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105
- 1 2 di Mauro, M. P.; et al. (October 2006). "Asteroseismology of K giants". In Fletcher, Karen; Thompson, Michael. Proceedings of SOHO 18/GONG 2006/HELAS I, Beyond the spherical Sun (ESA SP-624). Proceedings of SOHO 18/GONG 2006/HELAS I 624 (Sheffield, UK). p. 118. Bibcode:2006ESASP.624E.118D.
- ↑ "HD 32887 -- Variable Star". SIMBAD Astronomical Object Database. Centre de Données astronomiques de Strasbourg. Retrieved 2006-10-29.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16
- ↑ Setiawan, J.; et al. (2006), "Multi-periodic oscillations of HD 32887 and HD 81797", Memorie della Società Astronomica Italiana 77: 510, arXiv:astro-ph/0505184, Bibcode:2006MmSAI..77..510S
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