Epsilon2 Arae

For other star systems with this Bayer designation, see Epsilon Arae.
Epsilon2 Arae
The location of ε2 Arae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ara
Right ascension 17h 03m 08.754s[1]
Declination −53° 14′ 12.97″[1]
Apparent magnitude (V) 5.270[2] (5.44 + 8.65)[3]
Characteristics
Spectral type F5 V Fe+0.5[4] + DA3.2[5]
U−B color index +0.015[6]
B−V color index +0.498±0.005[2]
Astrometry
Radial velocity (Rv)+4.9[7] km/s
Proper motion (μ) RA: −22.409 mas/yr[1]
Dec.: −143.793 mas/yr[1]
Parallax (π)37.3696±0.1347 mas[1]
Distance87.3 ± 0.3 ly
(26.76 ± 0.10 pc)
Absolute magnitude (MV)3.27[8]
Orbit[9]
Primaryε2 Ara Aa
Companionε2 Ara Ab
Period (P)41.3 yr
Semi-major axis (a)0.589″
Eccentricity (e)0.622
Inclination (i)133.8°
Longitude of the node (Ω)73.6°
Details
ε2 Ara Aa
Mass1.40+0.01
−0.02[10] M☉
Radius1.8[2] R☉
Luminosity4.56[2] L☉
Surface gravity (log g)4.29[8] cgs
Temperature6,577[8] K
Metallicity [Fe/H]+0.02[8] dex
Rotational velocity (v sin i)45.4[11] km/s
Age1.77+0.29
−0.26[10] Gyr
ε2 Ara C
Mass0.65[5] M☉
Temperature15,570[5] K
Other designations
CPD−53°8316, GC 22956, GJ 3985, HD 153580, HIP 83431, HR 6314, SAO 244388, PPM 345633, WDS J17031-5314A[6]
Database references
SIMBADdata

Epsilon2 Arae is a double star in the southern constellation of Ara. Its name is a Bayer designation that is Latinized from ε2 Arae, and abbreviated Epsilon2 Ara or ε2 Ara. Based on parallax measurements, it is 89 light-years (27 parsecs) distant from Earth. With a combined apparent visual magnitude of 5.27,[2] this system is faintly visible to the naked eye as a point of light.

The brighter star is a magnitude 5.44 F-type main sequence star with a stellar classification of F5 V Fe+0.5.[4] The Fe+0.5 notation indicates that it has a somewhat higher than normal abundance of iron. It has an estimated age of 1.8[10] billion years and a relatively high rate of rotation with a projected rotational velocity of 45 km/s.[11] This star has 1.4[10] times the mass of the Sun and 1.8 times the Sun's radius.[2] It is radiating 4.56[2] times the luminosity of the Sun from its photosphere at an effective temperature of 6,577 K.[8] The metallicity of the star, a measure of the abundance of more massive elements, is similar to the Sun.[8] It is a candidate pulsating star.[12]

There is a magnitude 8.65 stellar companion, component Ab, at an angular separation of 0.590 arcseconds.[3] The pair have an estimated orbital period of 41.3 years.[9] A common proper motion white dwarf companion, WD 1659-53, lies at an angular separation of 113.76″. Designated component C, it is magnitude 13.47 with a classification of DA3.2.[13][5]

References

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  1. ^ a b c d 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.
  2. ^ a b c d e f g Schofield, Mathew; et al. (2019), "The Asteroseismic Target List for Solar-like Oscillators Observed in 2 minute Cadence with the Transiting Exoplanet Survey Satellite", The Astrophysical Journal Supplement Series, 241 (1): 12, arXiv:1901.10148, Bibcode:2019ApJS..241...12S, doi:10.3847/1538-4365/ab04f5.
  3. ^ a b 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, S2CID 14878976.
  4. ^ a b Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
  5. ^ a b c d Holberg, J. B.; et al. (November 2013), "Where are all the Sirius-like binary systems?", Monthly Notices of the Royal Astronomical Society, 435 (3): 2077–2091, arXiv:1307.8047, Bibcode:2013MNRAS.435.2077H, doi:10.1093/mnras/stt1433.
  6. ^ a b "* eps02 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-03-03.
  7. ^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics Supplement Series, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  8. ^ a b c d e f Balachandran, Suchitra (May 1, 1990), "Lithium depletion and rotation in main-sequence stars", Astrophysical Journal, Part 1, 354: 310–332, Bibcode:1990ApJ...354..310B, doi:10.1086/168691.
  9. ^ a b Tokovinin, Andrei (July 2017), "Orbit Alignment in Triple Stars", The Astrophysical Journal, 844 (2): 103, arXiv:1706.00748, Bibcode:2017ApJ...844..103T, doi:10.3847/1538-4357/aa7746, ISSN 0004-637X.
  10. ^ a b c d Aguilera-Gómez, Claudia; et al. (June 2018), "Lithium abundance patterns of late-F stars: an in-depth analysis of the lithium desert", Astronomy & Astrophysics, 614: A55, arXiv:1803.05922, Bibcode:2018A&A...614A..55A, doi:10.1051/0004-6361/201732209, eISSN 1432-0746, ISSN 0004-6361.
  11. ^ a b Schröder, C.; et al. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377.[permanent dead link]
  12. ^ Baade, D.; Kjeldsen, H. (July 1997), "A spectroscopic search for high azimuthal-order pulsation in broad-lined late F- and early G-stars.", Astronomy and Astrophysics, 323: 429–441, Bibcode:1997A&A...323..429B.
  13. ^ "GJ 2125 -- White Dwarf", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2010-07-28.
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