Epsilon2 Arae

Epsilon² Arae
	The location of ε2 Arae (circled)
Observation data; Epoch J2000 Equinox J2000
Constellation	Ara
Right ascension	17h 03m 08.754s
Declination	−53° 14′ 12.97″
Apparent magnitude (V)	5.270 (5.44 + 8.65)
Characteristics
Spectral type	F5 V Fe+0.5 + DA3.2
U−B color index	+0.015
B−V color index	+0.498±0.005
Astrometry
Radial velocity (Rv)	+4.9 km/s
Proper motion (μ)	RA: −22.409 mas/yr ; Dec.: −143.793 mas/yr
Parallax (π)	37.3696±0.1347 mas
Distance	87.3 ± 0.3 ly ; (26.76 ± 0.10 pc)
Absolute magnitude (MV)	3.27
Orbit
Primary	ε2 Ara Aa
Companion	ε2 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
Mass	1.40+0.01; −0.02 M☉
Radius	1.8 R☉
Luminosity	4.56 L☉
Surface gravity (log g)	4.29 cgs
Temperature	6,577 K
Metallicity [Fe/H]	+0.02 dex
Rotational velocity (v sin i)	45.4 km/s
Age	1.77+0.29; −0.26 Gyr
ε2 Ara C
Mass	0.66±0.07 M☉
Radius	0.0124±0.0003 R☉
Surface gravity (log g)	8.07±0.04 cgs
Temperature	15,507±230 K
Other designations
	CPD−53°8316, GC 22956, GJ 3985, HD 153580, HIP 83431, HR 6314, SAO 244388, PPM 345633, WDS J17031-5314A
Database references
SIMBAD	data

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.^[13]

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.^[14]^[5]

References

^ ^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.
^ ^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.
^ ^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.
^ ^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.
^ ^a ^b 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.
^ ^a ^b "* eps02 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-03-03.
^ 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.
^ ^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.
^ ^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.
^ ^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.
^ ^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]}
^ ^a ^b ^c ^d Bédard, A.; et al. (2017), "Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius Relation", The Astrophysical Journal, 848 (1): 11, arXiv:1709.02324, Bibcode:2017ApJ...848...11B, doi:10.3847/1538-4357/aa8bb6, S2CID 119359723.
^ 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.
^ "GJ 2125 -- White Dwarf", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2010-07-28.

External links

[Gaia_DR3-1] 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.

[Schofield_et_al_2019-2] ^ ^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.

[mnras389_2_869-3] 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.

[aj132_1_161-4] 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.

[Holberg_et_al_2013-5] 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.

[SIMBAD-6] "* eps02 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-03-03.

[aaass501_3_941-7] 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.

[apj354-8] ^ ^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.

[Tokovinin2017-9] 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.

[Aguilera-Gómez_et_al_2018-10] 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.

[aaa493_3_1099-11] 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]}

[Bédard_et_al_2017-12] Bédard, A.; et al. (2017), "Measurements of Physical Parameters of White Dwarfs: A Test of the Mass-Radius Relation", The Astrophysical Journal, 848 (1): 11, arXiv:1709.02324, Bibcode:2017ApJ...848...11B, doi:10.3847/1538-4357/aa8bb6, S2CID 119359723.

[Baade_Kjeldsen_1997-13] 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.

[SIMBAD2-14] "GJ 2125 -- White Dwarf", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2010-07-28.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

Epsilon2 Arae

References

External links

Portal di Ensiklopedia Dunia