Epsilon Leporis

Epsilon Leporis, Latinized from ε Leporis, 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]

ε Leporis

Location of ε Leporis (circled)
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)	15.5999 ± 0.1074 mas[5]
Distance	209 ± 1 ly (64.1 ± 0.4 pc)
Absolute magnitude (MV)	–1.02 ± 0.10[6]
Details[6]
Mass	1.70±0.19 M☉
Radius	40.1±3.2 R☉
Luminosity	372[7] L☉
Surface gravity (log g)	1.43±0.09 cgs
Temperature	4,131 K
Metallicity [Fe/H]	–0.02 dex
Age	1.72±0.47 Gyr
Other designations
ε Lep, 2 Leporis, NSV 1826, BD−22° 1000, FK5 186, HD 32887, HIP 23685, HR 1654, SAO 170051[8]
Database references
SIMBAD	data

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^[7] times as great. The outer atmosphere is cooler than the Sun's with an effective temperature of 4,131 K,^[6] giving it the orange hue of a K-type star.^[9] In terms of its composition, this star shows a similar abundance of elements other than hydrogen and helium to the Sun.^[6]

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.^[10]

References

1. 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. S2CID 18759600.
2. Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G
3. 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, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
4. Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W
5. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
6. 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, S2CID 9341088.
7. di Mauro, M. P.; Cardini, D. (October 2006), "Asteroseismology of K giants", in Fletcher, Karen; Thompson, Michael (eds.), Proceedings of SOHO 18/GONG 2006/HELAS I, Beyond the spherical Sun (ESA SP-624), vol. 624, Sheffield, UK, p. 118, Bibcode:2006ESASP.624E.118D{{citation}}: CS1 maint: location missing publisher (link)
8. "eps Lep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-10-29.
9. "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
10. 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