# 4 Centauri

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Star in the constellation Centaurus

This article is about h Centauri; not to be confused with [H Centauri](/source/V945_Centauri).

4 Centauri Location of 4 Centauri (circled in red) Observation data Epoch J2000.0 Equinox ICRS Constellation Centaurus[1] A Right ascension 13h 53m 12.53829s[2] Declination −31° 55′ 39.4304″[2] Apparent magnitude (V) +4.72[3] B Right ascension 13h 53m 12.43506s[4] Declination −31° 55′ 54.1506″[4] Apparent magnitude (V) +8.47[5]) Characteristics A Evolutionary stage main sequence[2] Spectral type B6IV[6] U−B color index −0.56[7] B−V color index −0.14[7] B Evolutionary stage main sequence[4] Spectral type Am[6] U−B color index +0.10[8] B−V color index +0.30[8] Astrometry A Radial velocity (Rv) +5.2±2[9] km/s Proper motion (μ) RA: −10.428[2] mas/yr Dec.: −10.710[2] mas/yr Parallax (π) 4.8225±0.1539 mas[2] Distance 680 ± 20 ly (207 ± 7 pc) Absolute magnitude (MV) −1.66[1] B Radial velocity (Rv) +9±10[9] km/s Proper motion (μ) RA: −10.905[4] mas/yr Dec.: −10.625[4] mas/yr Parallax (π) 4.1269±0.1312 mas[4] Distance 790 ± 30 ly (242 ± 8 pc) Orbit[6] Primary 4 Cen Aa Name 4 Cen Ab Period (P) 6.930137±0.000015 d Eccentricity (e) 0.25±0.10 Argument of periastron (ω) (secondary) 152±17° Semi-amplitude (K1) (primary) 21.0±1.5 km/s Orbit[6] Primary 4 Cen Ba Name 4 Cen Bb Period (P) 4.8390±0.0001 d Eccentricity (e) 0.05±0.02 Periastron epoch (T) 2442916.55±0.09 Argument of periastron (ω) (secondary) 51±20° Semi-amplitude (K1) (primary) 16.9±3.5 km/s Details Aa Mass 7.7[10] M☉ Radius 6.2[2] R☉ Luminosity 687[11] L☉ Surface gravity (log g) 3.43[2] cgs Temperature 14,322[11] K Metallicity [Fe/H] −1.06[2] dex Rotation 27.2 days[12] Age 51[13] Myr Ab Mass 0.75[10] M☉ Details Ba Mass 1.9[10] M☉ Radius 2.48[14] R☉ Luminosity 17.0[14] L☉ Surface gravity (log g) 3.88[14] cgs Temperature 7,440[14] K Bb Mass 0.22[10] M☉ Other designations h Cen, 4 Cen, HD 120955, HR 5221, CCDM J13532-3156[15] A: CD−31°10729, GC 18755, HIP 67786, SAO 204944[16] B: CD−31°10727, GC 18754, SAO 204943[17] Database references SIMBAD data 4 Cen B

**4 Centauri** is a [multiple star](/source/Multiple_star) in the [constellation](/source/Constellation) [Centaurus](/source/Centaurus), approximately 640 [light years](/source/Light_year) from [Earth](/source/Earth). It has a combined [apparent magnitude](/source/Apparent_magnitude) of +4.71.[18] The primary is a blue-white [B-type](/source/Stellar_classification) [subgiant](/source/Subgiant) with a spectroscopic companion, while the secondary is an [Am star](/source/Am_star) also with a spectroscopic companion.

4 Centauri is a hierarchical quadruple [star system](/source/Star_system). The primary component of the system, 4 Centauri A, is a [spectroscopic binary](/source/Spectroscopic_binary), meaning that its components cannot be [resolved](/source/Angular_resolution) but periodic [Doppler shifts](/source/Doppler_shift) in its [spectrum](/source/Stellar_spectrum) show that it must be orbiting. 4 Centauri A has an [orbital period](/source/Orbital_period) of 6.927 days and an [eccentricity](/source/Orbital_eccentricity) of 0.23. Because light from only one of the stars can be detected (i.e. it is a single-lined spectroscopic binary), some parameters such as its inclination are unknown.[19] The secondary component, is also a single-lined spectroscopic binary. It has an orbital period of 4.839 days and an eccentricity of 0.05. The secondary component is a metallic-lined [A-type star](/source/A-type_star). The two pairs themselves are separated by 14 arcseconds; one orbit would take at least 55,000 years.[6]

## References

1. ^ [***a***](#cite_ref-xhip_1-0) [***b***](#cite_ref-xhip_1-1) Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *[Astronomy Letters](/source/Astronomy_Letters)*. **38** (5): 331. [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971). [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A). [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [XHIP record for this object](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ681510a8389ecb&-out.src=V%2F137D%2FXHIP&-nav=cat%3AV%2F137D%26tab%3A{V%2F137D%2FXHIP}%26key%3Asource%3DV%2F137D%2FXHIP%26HTTPPRM%3A&-source=V%2F137D%2FXHIP&-out=HIP&HIP=67786&-out=Comp&-out=Gr&-out=RAJ2000&-out=DEJ2000&-out=Dist&-out=X&-out=Y&-out=Z&-out=SpType&-out=Simbad&-out=Hpmag&-out=Lum&-out=Cst) at [VizieR](/source/VizieR).

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1. ^ [***a***](#cite_ref-dr3b_4-0) [***b***](#cite_ref-dr3b_4-1) [***c***](#cite_ref-dr3b_4-2) [***d***](#cite_ref-dr3b_4-3) [***e***](#cite_ref-dr3b_4-4) [***f***](#cite_ref-dr3b_4-5) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D6171681881946274304%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

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1. **[^](#cite_ref-oelkers2018_12-0)** Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott (2018). ["Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey"](https://doi.org/10.3847%2F1538-3881%2Faa9bf4). *The Astronomical Journal*. **155** (1): 39. [arXiv](/source/ArXiv_(identifier)):[1711.03608](https://arxiv.org/abs/1711.03608). [Bibcode](/source/Bibcode_(identifier)):[2018AJ....155...39O](https://ui.adsabs.harvard.edu/abs/2018AJ....155...39O). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/aa9bf4](https://doi.org/10.3847%2F1538-3881%2Faa9bf4).

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1. **[^](#cite_ref-15)** ["* 4 Cen"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+4+Cen). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 8 February 2018.

1. **[^](#cite_ref-16)** ["* 4 Cen A"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+4+Cen+A). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 8 February 2018.

1. **[^](#cite_ref-17)** ["* 4 Cen B"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+4+Cen+B). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 8 February 2018.

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1. **[^](#cite_ref-19)** Paddock, G. F. (1917). ["The Spectroscopic Binary H 4 Centauri"](https://zenodo.org/record/1431275). *Publications of the Astronomical Society of the Pacific*. **29** (167): 56. [Bibcode](/source/Bibcode_(identifier)):[1917PASP...29...56P](https://ui.adsabs.harvard.edu/abs/1917PASP...29...56P). [doi](/source/Doi_(identifier)):[10.1086/122588](https://doi.org/10.1086%2F122588). [S2CID](/source/S2CID_(identifier)) [120812946](https://api.semanticscholar.org/CorpusID:120812946).

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 [4 Centauri](https://en.wikipedia.org/wiki/4_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/4_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.