# SV Centauri

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/SV_Centauri
> Markdown URL: https://mediated.wiki/source/SV_Centauri.md
> Source: https://en.wikipedia.org/wiki/SV_Centauri
> Source revision: 1351561511
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Star in the constellation Centaurus

SV Centauri A blue band light curve for SV Centauri, plotted from ASAS data[1] Observation data Epoch J2000 Equinox J2000 Constellation Centaurus Right ascension 11h 47m 57.2195s[2] Declination −60° 33′ 57.757″[2] Apparent magnitude (V) 8.71 to 9.98[3] Characteristics Spectral type B1V + B6.5III[4] U−B color index −0.74[5] B−V color index 0.06[5] Variable type Eclipsing binary (β Lyrae)[3] Astrometry Radial velocity (Rv) −27.7 ± 6.3[4] km/s Proper motion (μ) RA: −6.109[2] mas/yr Dec.: 0.291[2] mas/yr Parallax (π) 0.4876±0.0352 mas[2] Distance 6,700 ± 500 ly (2,100 ± 100 pc) Details[4] Primary Mass 7.7 M☉ Radius 6.8 R☉ Luminosity 11,700 L☉ Temperature 23,000 K Secondary Mass 9.6 M☉ Radius 7.4 R☉ Luminosity 1900 L☉ Temperature 14,000 K Other designations SV Centauri, CD−59 3950, HD 102552[6] Database references SIMBAD data

**SV Centauri** is a [variable star](/source/Variable_star) in the [constellation](/source/Constellation) [Centaurus](/source/Centaurus). An [eclipsing binary](/source/Eclipsing_binary), its visual [apparent magnitude](/source/Apparent_magnitude) has a maximum of 8.71, fading to 9.98 during primary eclipse and 9.42 during secondary eclipse.[3] From its brightness, it's estimated to be around 6,000 [light-years](/source/Light-year) (1,800 [parsecs](/source/Parsec)) away from Earth.[4] [Parallax](/source/Parallax) measurements from [Gaia Data Release 2](/source/Gaia_Data_Release_2) yield a similar distance of around 2,100 [pc](/source/Parsec).[2] [Henrietta Leavitt](/source/Henrietta_Leavitt) announced the discovery of this variable star, in 1906, when it was called CPD-59° 3809.[7] It was given its [variable star designation](/source/Variable_star_designation), SV Centauri, in 1907.[8]

SV Centauri is a [contact binary](/source/Contact_binary) made of two hot B-type stars with [spectral types](/source/Spectral_type) of B1V and B6.5III and [effective temperatures](/source/Effective_temperature) of 23,000 and 14,000 [K](/source/Kelvin). The primary component, the brighter star with 11,700 times the [solar luminosity](/source/Solar_luminosity), is the less massive one with 7.7 times the [solar mass](/source/Solar_mass) and has a radius of 6.8 times the [solar radius](/source/Solar_radius). The secondary component has a mass equal to 9.6 solar masses, radius of 7.4 solar radii and a brightness 1,900 times larger than the Sun's. The separation between the center of each star is only 15.3 solar radii. The system is viewed from a high [inclination](/source/Inclination) of 81.8°.[4]

The [orbital period](/source/Orbital_period) of SV Centauri is [monotonically](/source/Monotonic_function) decreasing at a very fast mean rate of 2.1 seconds per year, the largest rate for any known system. The first observations of the system, in 1894, revealed a period of 1.6606 days, which decreased to 1.6581 days in 1993,[9] showing a decrease rate that is variable with time, but with time intervals of 10 to 30 years when it is constant. The transition between such intervals of constant change can be accompanied by very fast decreases in the period, such as of 15 seconds per year in 1975.[10]

The most probable explanation for the period decrease is mass transfer from the less massive to the more massive star and subsequent mass loss through the L3 [Lagrangian point](/source/Lagrangian_point) of the system, which is located on the outer side of the more massive star.[4][11] The mass loss causes loss of [angular momentum](/source/Angular_momentum), which is compensated by a decrease in the separation between the stars. In this model, the system is losing mass at a rate of about 5 ×10−5 solar masses per year; the variation of this rate causes the variation in the rate of period decrease.[4] The alternative possibility is mass transfer from the more massive to the less massive star, which naturally tends to decrease the orbital period. This may create an [accretion disk](/source/Accretion_disk) around the less massive star, similar to [Beta Lyrae](/source/Beta_Lyrae).[12]

## References

1. **[^](#cite_ref-ASASServer_1-0)** ["ASAS All Star Catalogue"](http://www.astrouw.edu.pl/asas/?page=aasc). The All Sky Automated Survey. Retrieved 8 December 2021.

1. ^ [***a***](#cite_ref-gaiadr2_2-0) [***b***](#cite_ref-gaiadr2_2-1) [***c***](#cite_ref-gaiadr2_2-2) [***d***](#cite_ref-gaiadr2_2-3) [***e***](#cite_ref-gaiadr2_2-4) [***f***](#cite_ref-gaiadr2_2-5) [Brown, A. G. A.](/source/Anthony_Brown_(scientist)); et al. ([Gaia collaboration](/source/Data_Processing_and_Analysis_Consortium)) (August 2018). ["*Gaia* Data Release 2: Summary of the contents and survey properties"](https://doi.org/10.1051%2F0004-6361%2F201833051). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **616**. A1. [arXiv](/source/ArXiv_(identifier)):[1804.09365](https://arxiv.org/abs/1804.09365). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...616A...1G](https://ui.adsabs.harvard.edu/abs/2018A&A...616A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201833051](https://doi.org/10.1051%2F0004-6361%2F201833051). [Gaia DR2 record for this source](https://vizier.u-strasbg.fr/viz-bin/VizieR-S?Gaia%20DR2%205335388664983921024) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-GCVS_3-0) [***b***](#cite_ref-GCVS_3-1) [***c***](#cite_ref-GCVS_3-2) Samus, N. N.; Durlevich, O. V.; Kazarovets, E. V.; Kireeva, N. N.; Pastukhova, E. N. (2009). "VizieR On-line Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". *VizieR On-line Data Catalog: B/GCVS*. [Bibcode](/source/Bibcode_(identifier)):[2009yCat....102025S](https://ui.adsabs.harvard.edu/abs/2009yCat....102025S). Originally published in: [Bibcode](/source/Bibcode_(identifier)):[2017ARep...61...80S](https://ui.adsabs.harvard.edu/abs/2017ARep...61...80S); [Bibcode](/source/Bibcode_(identifier)):[2017AZh....94...87S](https://ui.adsabs.harvard.edu/abs/2017AZh....94...87S)

1. ^ [***a***](#cite_ref-Drechsel1982_4-0) [***b***](#cite_ref-Drechsel1982_4-1) [***c***](#cite_ref-Drechsel1982_4-2) [***d***](#cite_ref-Drechsel1982_4-3) [***e***](#cite_ref-Drechsel1982_4-4) [***f***](#cite_ref-Drechsel1982_4-5) [***g***](#cite_ref-Drechsel1982_4-6) Drechsel, H.; Rahe, J.; Wargau, W.; Wolf, B. (June 1982). "The interacting early-type contact binary SV Centauri". *Astronomy and Astrophysics*. **110** (2): 246–262. [Bibcode](/source/Bibcode_(identifier)):[1982A&A...110..246D](https://ui.adsabs.harvard.edu/abs/1982A&A...110..246D).

1. ^ [***a***](#cite_ref-Schild1983_5-0) [***b***](#cite_ref-Schild1983_5-1) Schild, R. E.; Garrison, R. F.; Hiltner, W. A. (1983). "UBV photometry for southern OB stars". *Astrophysical Journal Supplement Series*. **51**: 321. [Bibcode](/source/Bibcode_(identifier)):[1983ApJS...51..321S](https://ui.adsabs.harvard.edu/abs/1983ApJS...51..321S). [doi](/source/Doi_(identifier)):[10.1086/190852](https://doi.org/10.1086%2F190852).

1. **[^](#cite_ref-SIMBAD_6-0)** ["V* SV Cen — Eclipsing binary of W UMa type (contact binary)"](http://simbad.u-strasbg.fr/simbad/sim-id?Ident=SV+Cen). *SIMBAD*. [Centre de Données astronomiques de Strasbourg](/source/Centre_de_Donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2017-11-29.

1. **[^](#cite_ref-Leavitt1906_7-0)** Leavitt, Henrietta S.; Pickering, Edward C. (November 1906). ["Thirty-Six New Variable Stars"](https://articles.adsabs.harvard.edu/pdf/1906HarCi.122....1L). *Harvard College Observatory Circular*. **122**: 1–4. [Bibcode](/source/Bibcode_(identifier)):[1906HarCi.122....1L](https://ui.adsabs.harvard.edu/abs/1906HarCi.122....1L). Retrieved 14 January 2025.

1. **[^](#cite_ref-Duner1907_8-0)** Dunér; Hartwig; Müller (November 1907). ["Benennung von neu entdeckten veränderlichen Sternen"](https://articles.adsabs.harvard.edu/pdf/1907AN....176..181.). *Astronomische Nachrichten*. **176** (12): 181–194. [doi](/source/Doi_(identifier)):[10.1002/asna.19071761202](https://doi.org/10.1002%2Fasna.19071761202). Retrieved 14 January 2025.

1. **[^](#cite_ref-Drechsel1993_9-0)** Drechsel, H.; Lorenz, R. (April 1993). "Period of SV Centauri Continues Decreasing". *Information Bulletin on Variable Stars*. **3868** (1): 1. [Bibcode](/source/Bibcode_(identifier)):[1993IBVS.3868....1D](https://ui.adsabs.harvard.edu/abs/1993IBVS.3868....1D).

1. **[^](#cite_ref-Herczeg1985_10-0)** Herczeg, T. J.; Drechsel, H. (September 1985). "The period of SV Centauri". *Astrophysics and Space Science*. **114** (1): 1–13. [Bibcode](/source/Bibcode_(identifier)):[1985Ap&SS.114....1H](https://ui.adsabs.harvard.edu/abs/1985Ap&SS.114....1H). [doi](/source/Doi_(identifier)):[10.1007/BF02463863](https://doi.org/10.1007%2FBF02463863). [S2CID](/source/S2CID_(identifier)) [121108005](https://api.semanticscholar.org/CorpusID:121108005).

1. **[^](#cite_ref-Drechsel1994_11-0)** Drechsel, H. (1994). "On the evolution state of the interacting binary SV Cen". *Astronomische Gesellschaft Abstract Series*. **10**: 95. [Bibcode](/source/Bibcode_(identifier)):[1994AGAb...10...95D](https://ui.adsabs.harvard.edu/abs/1994AGAb...10...95D).

1. **[^](#cite_ref-Linnell1991_12-0)** Linnell, Albert P.; Scheick, Xania (October 1991). "Does SV Centauri harbor an accretion disk?". *Astrophysical Journal*. **379**: 721–728. [Bibcode](/source/Bibcode_(identifier)):[1991ApJ...379..721L](https://ui.adsabs.harvard.edu/abs/1991ApJ...379..721L). [doi](/source/Doi_(identifier)):[10.1086/170547](https://doi.org/10.1086%2F170547).

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

---
Adapted from the Wikipedia article [SV Centauri](https://en.wikipedia.org/wiki/SV_Centauri) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/SV_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.