# Upsilon2 Centauri

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Binary star system in the constellation Centaurus

For other stars with this Bayer designation, see [υ Centauri](/source/Upsilon_Centauri).

Upsilon2 Centauri Location of υ2 Centauri (circled in red) Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) Constellation Centaurus Right ascension 14h 01m 43.49909 s[1] Declination −45° 36′ 12.2767″[1] Apparent magnitude (V) +4.33[2] Characteristics Spectral type F7 II/III[3] U−B color index +0.26[2] B−V color index +0.61[2] Variable type None[4] Astrometry Radial velocity (Rv) −7.8±7.4[5] km/s Proper motion (μ) RA: +8.64±1.09 mas/yr[1] Dec.: −16.25±0.88 mas/yr[1] Parallax (π) 2.57±1.05 mas[1] Distance approx. 1,300 ly (approx. 400 pc) Absolute magnitude (MV) −3.51[4] Orbit[6] Period (P) 207.357 d Eccentricity (e) 0.55 Periastron epoch (T) 2423880.5 JD Argument of periastron (ω) (secondary) 88° Semi-amplitude (K1) (primary) 12.7 km/s Details Mass 6.86±0.39[7] M☉ Luminosity (bolometric) 3,919[7] L☉ Surface gravity (log g) 2.00[8] cgs Temperature 6,495[7] K Rotational velocity (v sin i) 0.0[8] km/s Age 45.9±4.0[9] Myr Other designations υ2 Cen, CD−44°9040, GC 18939, HD 122223, HIP 68523, HR 5260, SAO 224621[10] Database references SIMBAD data

**Upsilon2 Centauri** is a [binary star](/source/Binary_star)[6] system in the southern [constellation](/source/Constellation) [Centaurus](/source/Centaurus). Its name is a [Bayer designation](/source/Bayer_designation) that is [Latinized](/source/Romanization_of_Greek) from υ2 Centauri, and abbreviated Upsilon2 Cen or υ2 Cen. This system is visible to the [naked eye](/source/Naked_eye) as a point of light with a combined [apparent visual magnitude](/source/Apparent_visual_magnitude) of +4.33.[2] Based upon an annual [parallax shift](/source/Stellar_parallax) of 2.57 [mas](/source/Milliarcsecond) as seen from Earth,[1] this star is located roughly 1,300 [light years](/source/Light_year) from the [Sun](/source/Sun). Relative to its neighbors, the system has a [peculiar velocity](/source/Peculiar_velocity) of 39.2+8.8 −15.2 km/s and it may form a [runaway star](/source/Runaway_star) system.[9]

This is a single-lined [spectroscopic binary](/source/Spectroscopic_binary) star system with an [orbital period](/source/Orbital_period) of 207.357 days and an [eccentricity](/source/Orbital_eccentricity) of 0.55.[6] The primary component has the [spectrum](/source/Stellar_spectrum) of an [evolved](/source/Stellar_evolution) [F-type](/source/F-type_star) [giant](/source/Giant_star)/[bright giant](/source/Bright_giant) hybrid with a [stellar classification](/source/Stellar_classification) of F7 II/III.[3] It is around 46[9] million years old with 6.9 times the [mass of the Sun](/source/Mass_of_the_Sun). The star is radiating 3,919 times the [Sun's luminosity](/source/Sun's_luminosity) from its [photosphere](/source/Photosphere) at an [effective temperature](/source/Effective_temperature) of 6,495 K.[7]

## References

1. ^ [***a***](#cite_ref-vanLeeuwen2007_1-0) [***b***](#cite_ref-vanLeeuwen2007_1-1) [***c***](#cite_ref-vanLeeuwen2007_1-2) [***d***](#cite_ref-vanLeeuwen2007_1-3) [***e***](#cite_ref-vanLeeuwen2007_1-4) van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", *Astronomy and Astrophysics*, **474** (2): 653–664, [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752), [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357), [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600).

1. ^ [***a***](#cite_ref-fernie1983_2-0) [***b***](#cite_ref-fernie1983_2-1) [***c***](#cite_ref-fernie1983_2-2) [***d***](#cite_ref-fernie1983_2-3) Fernie, J. D. (1983), "New UBVRI photometry for 900 supergiants", *Astrophysical Journal Supplement Series*, **52**: 7, [Bibcode](/source/Bibcode_(identifier)):[1983ApJS...52....7F](https://ui.adsabs.harvard.edu/abs/1983ApJS...52....7F), [doi](/source/Doi_(identifier)):[10.1086/190856](https://doi.org/10.1086%2F190856).

1. ^ [***a***](#cite_ref-Houk1978_3-0) [***b***](#cite_ref-Houk1978_3-1) Houk, N. (1987), "Michigan Catalogue of two dimensional spectral types for the HD stars", *Michigan Spectral Survey*, **2**, [Bibcode](/source/Bibcode_(identifier)):[1978mcts.book.....H](https://ui.adsabs.harvard.edu/abs/1978mcts.book.....H).

1. ^ [***a***](#cite_ref-Eggen1985_4-0) [***b***](#cite_ref-Eggen1985_4-1) Eggen, O. J. (July 1985), "Cepheids and nonvariable supergiants", *Astronomical Journal*, **90**: 1260–1277, [Bibcode](/source/Bibcode_(identifier)):[1985AJ.....90.1260E](https://ui.adsabs.harvard.edu/abs/1985AJ.....90.1260E), [doi](/source/Doi_(identifier)):[10.1086/113834](https://doi.org/10.1086%2F113834).

1. **[^](#cite_ref-deBruijne2012_5-0)** de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", *Astronomy & Astrophysics*, **546**: 14, [arXiv](/source/ArXiv_(identifier)):[1208.3048](https://arxiv.org/abs/1208.3048), [Bibcode](/source/Bibcode_(identifier)):[2012A&A...546A..61D](https://ui.adsabs.harvard.edu/abs/2012A&A...546A..61D), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201219219](https://doi.org/10.1051%2F0004-6361%2F201219219), [S2CID](/source/S2CID_(identifier)) [59451347](https://api.semanticscholar.org/CorpusID:59451347), A61.

1. ^ [***a***](#cite_ref-Pourbaix_6-0) [***b***](#cite_ref-Pourbaix_6-1) [***c***](#cite_ref-Pourbaix_6-2) Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", *Astronomy & Astrophysics*, **424**: 727–732, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0406573](https://arxiv.org/abs/astro-ph/0406573), [Bibcode](/source/Bibcode_(identifier)):[2004A&A...424..727P](https://ui.adsabs.harvard.edu/abs/2004A&A...424..727P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20041213](https://doi.org/10.1051%2F0004-6361%3A20041213), [S2CID](/source/S2CID_(identifier)) [119387088](https://api.semanticscholar.org/CorpusID:119387088).

1. ^ [***a***](#cite_ref-Hohle2010_7-0) [***b***](#cite_ref-Hohle2010_7-1) [***c***](#cite_ref-Hohle2010_7-2) [***d***](#cite_ref-Hohle2010_7-3) Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", *Astronomische Nachrichten*, **331** (4): 349, [arXiv](/source/ArXiv_(identifier)):[1003.2335](https://arxiv.org/abs/1003.2335), [Bibcode](/source/Bibcode_(identifier)):[2010AN....331..349H](https://ui.adsabs.harvard.edu/abs/2010AN....331..349H), [doi](/source/Doi_(identifier)):[10.1002/asna.200911355](https://doi.org/10.1002%2Fasna.200911355), [S2CID](/source/S2CID_(identifier)) [111387483](https://api.semanticscholar.org/CorpusID:111387483).

1. ^ [***a***](#cite_ref-Mallik2003_8-0) [***b***](#cite_ref-Mallik2003_8-1) Mallik, Sushma V.; et al. (October 2003), "Lithium and rotation in F and G dwarfs and subgiants", *Astronomy and Astrophysics*, **409**: 251–261, [Bibcode](/source/Bibcode_(identifier)):[2003A&A...409..251M](https://ui.adsabs.harvard.edu/abs/2003A&A...409..251M), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20031084](https://doi.org/10.1051%2F0004-6361%3A20031084).

1. ^ [***a***](#cite_ref-Tetzlaff2011_9-0) [***b***](#cite_ref-Tetzlaff2011_9-1) [***c***](#cite_ref-Tetzlaff2011_9-2) Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", *[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*, **410** (1): 190–200, [arXiv](/source/ArXiv_(identifier)):[1007.4883](https://arxiv.org/abs/1007.4883), [Bibcode](/source/Bibcode_(identifier)):[2011MNRAS.410..190T](https://ui.adsabs.harvard.edu/abs/2011MNRAS.410..190T), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2010.17434.x](https://doi.org/10.1111%2Fj.1365-2966.2010.17434.x), [S2CID](/source/S2CID_(identifier)) [118629873](https://api.semanticscholar.org/CorpusID:118629873).

1. **[^](#cite_ref-SIMBAD_10-0)** ["ups02 Cen"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ups02+Cen), *[SIMBAD](/source/SIMBAD)*, [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg), retrieved 2017-08-29

v t e Constellation of Centaurus List of stars in Centaurus Centaurus in Chinese astronomy Stars Bayer α A (Rigil Kentaurus) B (Toliman) C (Proxima Centauri) β (Hadar) γ δ ε ζ (Leepwal) η θ (Menkent) ι (Kulou) κ λ μ ν (Heng) ξ1 ξ2 ο1 ο2 π ρ σ τ υ1 υ2 φ χ ψ x1 x2 C3 D E F G H J K M N Q Flamsteed 1 (i) 2 (g) 3 (k) 4 (h) Variable R T V Y RR SV SX BV DY UY V346 V553 V744 V752 V761 (a) V763 (C1) V766 V779 (Krzemiński's star) V803 V810 V816 (Przybylski's Star) V831 V842 V885 V886 V863 V1032 V1369 V1400 V1935 HR 4460 (A) 4466 (C2) 4499 4522 4523 4537 (j) 4546 (B) 4721 4748 (u) 4796 4817 (l) 4831 (w) 4874 (p) 4888 (e) 4889 (n) 4940 (f) 4979 4989 5006 (r) 5041 (m) 5089 (d) 5174 (z) 5222 (y) 5224 5241 5297 5358 (v) 5371 5471 (b) 5485 (c1) 5489 (c2) HD 97413 98176 100453 101581 101930 102117 (Uklun) 103197 107914 108236 109749 110113 113538 113766 114386 114729 115600 116434 (Matza) 117207 117618 (Dofida) 117939 120411 121228 121504 124448 (Popper's Star) 125072 125595 131399 Other 2MASS J1126−5003 2M1207 Gaia BH2 HD 131399 Ab PSR B1259−63 PSR J1311−3430 TOI-763 WASP-15 (Nyamien) WASP-41 WASP-42 WASP-167/KELT-13 Exoplanets 2M1207b b Centauri b HD 101930 b HD 102117 b (Leklsullun) HD 103197 b HD 109749 b HD 113538 b c HD 114386 b HD 114729 b HD 117207 b HD 117618 b (Noifasui) HD 121504 b HIP 65426 b (Najsakopajk) HIP 67522 b NGTS-13b Proxima Centauri b c d WASP-15b (Asye) Star clusters NGC 3766 4230 4507 5281 5286 5316 5460 5617 5662 Other IC 2944 ω Centauri Scorpius–Centaurus association Stock 16 Nebulae NGC 3918 5307 Other Boomerang Nebula Fleming 1 G292.0+1.8 G306.3-0.9 Gum 41 IC 2944 IRAS 13208−6020 RCW 79 RCW 86 Southern Crab Nebula SuWt 2 Galaxies NGC 3557 3568 3749 3783 4444 4603 4622 4650A 4683 4696 4706 4709 4729 4730 4743 4744 4909 4930 4945 4976 5011 A 5026 5064 5082 5090 5091 5102 5114 5121 5128 (Centaurus A) 5161 5206 5253 5266 5291 5398 5408 5419 5483 5516 Other ESO 269-57 ESO 325-4 ESO 383-76 ESO 444-46 Fourcade-Figueroa Object IC 3370 IC 4214 IC 4329A IRAS 13224−3809 J1144−4308 LEDA 677373 PKS 1144−379 PKS 1353−341 PKS 1424−418 Galaxy clusters Abell S740 Centaurus Cluster Shapley Supercluster Astronomical events GW190521 SN 185 SN 1895B (Z) SN 1972E SN 1986G J1407b SN 2019so Category

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Adapted from the Wikipedia article [Upsilon2 Centauri](https://en.wikipedia.org/wiki/Upsilon2_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Upsilon2_Centauri?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.