# RR Centauri

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Star in the constellation Centaurus

RR Centauri Light curve of RR Cen. Observation data Epoch J2000 Equinox J2000 Constellation Centaurus Right ascension 14h 16m 57.22s[1] Declination −57° 51′ 15.6″[1] Apparent magnitude (V) 7.27 - 7.68[2] Characteristics Spectral type F0 V[3] U−B color index +0.05[4] B−V color index +0.36[4] Variable type W Uma[2] Astrometry Radial velocity (Rv) -16.0 [5] km/s Proper motion (μ) RA: -52.00[6] mas/yr Dec.: -22.63[6] mas/yr Parallax (π) 10.16±0.61 mas[6] Distance 320 ± 20 ly (98 ± 6 pc) Absolute magnitude (MV) +1.882[3] Orbit[7] Primary RR Cen A Name RR Cen B Period (P) 0.60569 days Semi-major axis (a) 3.92 ± 0.19 R☉ Eccentricity (e) 0 Inclination (i) 81.00 ± 0.44° Details[7] RR Cen A Mass 1.82 ± 0.26 M☉ Radius 2.1 ± 0.01 R☉ Luminosity 8.89 L☉ Temperature 6,912 K RR Cen B Mass 0.38 ± 0.06 M☉ Radius 1.05 ± 0.03 R☉ Luminosity 2.2 L☉ Temperature 6,891 ± 13 K Other designations RR Cen, 2MASS J14165721-5751156, HD 124689, HIP 69779, SAO 241587, TYC 8686-210-1, Cordoba Durchmusterung CD-57 5498[1] Database references SIMBAD data

**RR Centauri** is a [variable star](/source/Variable_star) with an [apparent magnitude](/source/Apparent_magnitude) of +7.3 when it is at its brightest. It is located in the constellation of [Centaurus](/source/Centaurus), approximately 320 light years distant from the [Solar System](/source/Solar_System).[6]

The system is a contact binary of the [W UMa type](/source/W_Uma_star) - two stars in physical contact whose two components share a gaseous envelope — with a variation in brightness of 0.41 magnitude.[7] Its spectral type is A9V or F0V.[1] The binary nature of the star was discovered in 1896 by the Scottish-South African astronomer [Alexander Roberts](/source/Alexander_William_Roberts), so the system has been well observed for over a century.[8] The primary component has a mass of 1.82 solar masses, an effective temperature of around 6900 K, and a radius somewhat larger than twice the solar radius.[7] The secondary component is 0.39 solar masses, giving a mass ratio of the system (*q*) of 0.210. the secondary has a temperature of about 6890 K and a radius is almost equal to the solar radius.

The orbital period of this system is 0.6057 days (14.54 h). Calculations by astronomers from the Chinese Academy of Sciences show a possible cyclic variation in orbital period over 65.1±0.4 years whose amplitude is 0.0124±0.0007 d.[7] The origin of this periodic variation could be due to the gravitational influence of a third object yet observed. Superimposed on this variation seems to be a secular increase in the period of 1.21×10−7 d/a, suggesting that there is transfer of stellar mass from secondary to primary component. If this increase is confirmed, RR Centauri may evolve into a single rapidly rotating star.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## References

1. ^ [***a***](#cite_ref-SIMBAD_1-0) [***b***](#cite_ref-SIMBAD_1-1) [***c***](#cite_ref-SIMBAD_1-2) [***d***](#cite_ref-SIMBAD_1-3) ["V* RR Cen -- Eclipsing binary of W UMa type (contact binary)"](http://simbad.u-strasbg.fr/simbad/sim-id?protocol=html&Ident=RR+Cen&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id). *SIMBAD*. Centre de Données astronomiques de Strasbourg. Retrieved 2016-02-27.

1. ^ [***a***](#cite_ref-gcvs_2-0) [***b***](#cite_ref-gcvs_2-1) Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". *VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S*. **1**. [Bibcode](/source/Bibcode_(identifier)):[2009yCat....102025S](https://ui.adsabs.harvard.edu/abs/2009yCat....102025S).

1. ^ [***a***](#cite_ref-eker_3-0) [***b***](#cite_ref-eker_3-1) Eker, Z.; Bilir, S.; Yaz, E.; Demircan, O.; Helvaci, M. (2009). "New absolute magnitude calibrations for W Ursa Majoris type binaries". *Astronomische Nachrichten*. **330** (1): 68–76. [arXiv](/source/ArXiv_(identifier)):[0807.4989](https://arxiv.org/abs/0807.4989). [Bibcode](/source/Bibcode_(identifier)):[2009AN....330...68E](https://ui.adsabs.harvard.edu/abs/2009AN....330...68E). [doi](/source/Doi_(identifier)):[10.1002/asna.200811041](https://doi.org/10.1002%2Fasna.200811041). [S2CID](/source/S2CID_(identifier)) [15071352](https://api.semanticscholar.org/CorpusID:15071352).

1. ^ [***a***](#cite_ref-Loden_4-0) [***b***](#cite_ref-Loden_4-1) Loden, L.O. (1979). "Continued studies of loose clusterings in the Southern Milky Way". *Astronomy and Astrophysics Supplement*. **38**: 355. [Bibcode](/source/Bibcode_(identifier)):[1979A&AS...38..355L](https://ui.adsabs.harvard.edu/abs/1979A&AS...38..355L).

1. **[^](#cite_ref-kinematics_5-0)** Bilir, S; Karatas, Y; Demircan, O; Eker, Z (2005). ["Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation"](https://doi.org/10.1111%2Fj.1365-2966.2005.08609.x). *Monthly Notices of the Royal Astronomical Society*. **357** (2): 497–517. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0411291](https://arxiv.org/abs/astro-ph/0411291). [Bibcode](/source/Bibcode_(identifier)):[2005MNRAS.357..497B](https://ui.adsabs.harvard.edu/abs/2005MNRAS.357..497B). [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2005.08609.x](https://doi.org/10.1111%2Fj.1365-2966.2005.08609.x). [S2CID](/source/S2CID_(identifier)) [16274339](https://api.semanticscholar.org/CorpusID:16274339).

1. ^ [***a***](#cite_ref-aaa474_2_653_6-0) [***b***](#cite_ref-aaa474_2_653_6-1) [***c***](#cite_ref-aaa474_2_653_6-2) [***d***](#cite_ref-aaa474_2_653_6-3) van Leeuwen, F. (November 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-PASJ_7-0) [***b***](#cite_ref-PASJ_7-1) [***c***](#cite_ref-PASJ_7-2) [***d***](#cite_ref-PASJ_7-3) [***e***](#cite_ref-PASJ_7-4) Yuan-Gui, Y.; Sheng-Bang, Q.; Li-Ying, Z.; Jia-Jia, H.; Jin-Zhao, Y (2005). ["Photometric Investigations of Three Short-Period Binary Systems: GSC 0763–0572, RR Centauri, and Epsilon Coronae Australis"](https://doi.org/10.1093%2Fpasj%2F57.6.983). *Publications of the Astronomical Society of Japan*. **57** (6): 983–993. [Bibcode](/source/Bibcode_(identifier)):[2005PASJ...57..983Y](https://ui.adsabs.harvard.edu/abs/2005PASJ...57..983Y). [doi](/source/Doi_(identifier)):[10.1093/pasj/57.6.983](https://doi.org/10.1093%2Fpasj%2F57.6.983).

1. **[^](#cite_ref-Roberts_8-0)** Roberts, Alexander (1903). ["Determination of the Orbital Elements of RR Centauri from the Observed Light Curve"](https://doi.org/10.1093%2Fmnras%2F63.8.527). *Monthly Notices of the Royal Astronomical Society*. **63** (8): 540–549. [Bibcode](/source/Bibcode_(identifier)):[1903MNRAS..63..536R](https://ui.adsabs.harvard.edu/abs/1903MNRAS..63..536R). [doi](/source/Doi_(identifier)):[10.1093/mnras/63.8.527](https://doi.org/10.1093%2Fmnras%2F63.8.527).

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 [RR Centauri](https://en.wikipedia.org/wiki/RR_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/RR_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.