# HD 133880

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Variable star in the constellation Lupus

HD 133880 A light curve for HR Lupi, plotted from TESS data[1] Observation data Epoch J2000.0 Equinox J2000.0 Constellation Lupus[2] Right ascension 15h 08m 12.12388s[3] Declination −40° 35′ 02.1554″[3] Apparent magnitude (V) 5.76 - 5.81[4] Characteristics Evolutionary stage main sequence[5] Spectral type B8IVp Si λ4200[6] Variable type SX Arietis[4] Astrometry Proper motion (μ) RA: −28.686±0.085[3] mas/yr Dec.: −31.533±0.071[3] mas/yr Parallax (π) 9.4922±0.0786 mas[3] Distance 344 ± 3 ly (105.3 ± 0.9 pc) Absolute magnitude (MV) 0.53[2] Details Mass 3.20±0.15[7] M☉ Radius 2.01±0.32[8] R☉ Luminosity 105[8] L☉ Surface gravity (log g) 4.28[3] cgs Temperature 13,000±600[8] K Rotational velocity (v sin i) 103±10[8] km/s Age 16+4 −3[7] Myr Other designations HR Lupi, HIP 74066, HR 5624, SAO 225474[9] Database references SIMBAD data

**HD 133880**, also known as **HR 5624** and **HR Lupi**, is a [Bp star](/source/Bp_star) about 340 [light years](/source/Light_year) from the Earth, in the constellation [Lupus](/source/Lupus_(constellation)).[3] It is a 5th [magnitude](/source/Apparent_magnitude) star, and will be faintly visible to the [naked eye](/source/Naked_eye) of an observer far from [city lights](/source/Light_pollution). It is an [SX Arietis variable](/source/SX_Arietis_variable) star, varying from magnitude 5.76 to 5.81 over a period of 21.0594 hours.[4] HD 133880 is a member of the [Upper Centaurus–Lupus association](/source/Scorpius%E2%80%93Centaurus_association). It is a young star, estimated to have completed only 5±2 percent of its projected [main sequence](/source/Main_sequence) lifetime.[7] It is one of the few stars known to produce coherent pulsed radio radiation via electron cyclotron maser emission.[10]

The [spectrum](/source/Stellar_spectrum) of HD 133880 matches a B8 [subgiant](/source/Subgiant), but with unusually strong [absorption lines](/source/Absorption_line) of some metals, making it a member of the [chemically peculiar](/source/Chemically_peculiar) Ap/Bp star class. For this particular star, silicon lines at 4,200 [Å](/source/%C3%85ngstr%C3%B6m) are notably strong.[7] Its rotation rate is unusually fast for a star of this type.[8]

In 1985, Christoffel Waelkens found that HD 133880 is a variable star with a period of 0.87746±0.00001 days, varying by 0.15, 0.10 and 0.06 magnitudes in the U, B and V [bands](/source/Photometric_system#Photometric_letters) respectively.[11] In 1986, the star was given the variable star designation HR Lupi.[12] Later measurements of the period varied significantly, and can only be reconciled if the period varies in time.[13]

In 1990, John Landstreet found that HD 133880 has a very strong (several k[G)](/source/Gauss_(unit)) [magnetic field](/source/Magnetic_field), with the unusual property that its [quadrupole](/source/Quadrupole) term is stronger than the [dipole](/source/Dipole) term.[14] However a study in 2017 found the magnetic field was better described as a distorted asymmetric dipole, with a maximum strength of 12 kG, and an average strength of 4 kG.[15]

Much of the research interest in HD 133880 arises from its radio emissions. Jeremy Lim *et al.* observed the star with the [Australia Telescope Compact Array](/source/Australia_Telescope_Compact_Array) in 1995, and found that because the star's magnetic and rotation axes are not aligned, the 6 cm wavelength radiation they measured showed variation in both strength and polarization as the star rotated.[16] In 2018 Barnali Das *et al.* detected electron [cyclotron](/source/Cyclotron_radiation) [maser](/source/Maser) emission[17] from the star at 610 MHz, using the [GMRT](/source/Giant_Metrewave_Radio_Telescope). HD 133880 was the second star found to radiate in this way (after [CU Virginis](/source/CU_Virginis)). The radiation was found to vary by an order of magnitude as the star rotated, and had roughly 100 percent right [circular polarization](/source/Circular_polarization) when the emission peaked.[13]

## References

1. **[^](#cite_ref-MAST_1-0)** ["MAST: Barbara A. Mikulski Archive for Space Telescopes"](https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html). Space Telescope Science Institute. Retrieved 22 January 2023.

1. ^ [***a***](#cite_ref-xhip_2-0) [***b***](#cite_ref-xhip_2-1) 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=74066&-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).

1. ^ [***a***](#cite_ref-dr3_3-0) [***b***](#cite_ref-dr3_3-1) [***c***](#cite_ref-dr3_3-2) [***d***](#cite_ref-dr3_3-3) [***e***](#cite_ref-dr3_3-4) [***f***](#cite_ref-dr3_3-5) [***g***](#cite_ref-dr3_3-6) 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%3D6005290206037557760%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-IVSI_4-0) [***b***](#cite_ref-IVSI_4-1) [***c***](#cite_ref-IVSI_4-2) ["HR Lup"](https://www.aavso.org/vsx/index.php?view=detail.top&oid=17811). *The International Variable Star Index*. AAVSO. Retrieved 22 January 2023.

1. **[^](#cite_ref-zorec2012_5-0)** Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". *Astronomy and Astrophysics*. **537**: A120. [arXiv](/source/ArXiv_(identifier)):[1201.2052](https://arxiv.org/abs/1201.2052). [Bibcode](/source/Bibcode_(identifier)):[2012A&A...537A.120Z](https://ui.adsabs.harvard.edu/abs/2012A&A...537A.120Z). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201117691](https://doi.org/10.1051%2F0004-6361%2F201117691).

1. **[^](#cite_ref-Bychkov2021_6-0)** Bychkov, V. D.; Bychkova, L. V.; Madej, J. (August 2021). ["Catalog of averaged magnetic phase curves of stars. Second edition"](https://doi.org/10.1051%2F0004-6361%2F202040215). *Astronomy and Astrophysics*. **652**: A31. [arXiv](/source/ArXiv_(identifier)):[2004.14099](https://arxiv.org/abs/2004.14099). [Bibcode](/source/Bibcode_(identifier)):[2021A&A...652A..31B](https://ui.adsabs.harvard.edu/abs/2021A&A...652A..31B). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202040215](https://doi.org/10.1051%2F0004-6361%2F202040215).

1. ^ [***a***](#cite_ref-Landstreet2007_7-0) [***b***](#cite_ref-Landstreet2007_7-1) [***c***](#cite_ref-Landstreet2007_7-2) [***d***](#cite_ref-Landstreet2007_7-3) Landstreet, J. D.; Bagnulo, S.; Andretta, V.; Fossati, L.; Mason, E.; Silaj, J.; Wade, G. A. (August 2007). ["Searching for links between magnetic fields and stellar evolution: II. The evolution of magnetic fields as revealed by observations of Ap stars in open clusters and associations"](https://doi.org/10.1051%2F0004-6361%3A20077343). *Astronomy and Astrophysics*. **470** (2): 685. [arXiv](/source/ArXiv_(identifier)):[0706.0330](https://arxiv.org/abs/0706.0330). [Bibcode](/source/Bibcode_(identifier)):[2007A&A...470..685L](https://ui.adsabs.harvard.edu/abs/2007A&A...470..685L). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20077343](https://doi.org/10.1051%2F0004-6361%3A20077343).

1. ^ [***a***](#cite_ref-Bailey2012_8-0) [***b***](#cite_ref-Bailey2012_8-1) [***c***](#cite_ref-Bailey2012_8-2) [***d***](#cite_ref-Bailey2012_8-3) [***e***](#cite_ref-Bailey2012_8-4) Bailey, J. D.; Grunhut, J.; Shultz, M.; Wade, G.; Landstreet, J. D.; Bohlender, D.; Lim, J.; Wong, K.; Drake, S.; Linsky, J.; MiMeS Collaboration (June 2012). ["An analysis of the rapidly rotating Bp star HD 133880"](https://doi.org/10.1111%2Fj.1365-2966.2012.20881.x). *Monthly Notices of the Royal Astronomical Society*. **423** (1): 328–343. [arXiv](/source/ArXiv_(identifier)):[1203.5277](https://arxiv.org/abs/1203.5277). [Bibcode](/source/Bibcode_(identifier)):[2012MNRAS.423..328B](https://ui.adsabs.harvard.edu/abs/2012MNRAS.423..328B). [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2012.20881.x](https://doi.org/10.1111%2Fj.1365-2966.2012.20881.x).

1. **[^](#cite_ref-SIMBAD_9-0)** ["HR Lup -- alpha2 CVn Variable"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+Lup+--+alpha2+CVn+Variable). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2023-01-22.

1. **[^](#cite_ref-Das2020_10-0)** Das, Barnali; Chandra, Poonam; Wade, Gregg A. (November 2020). ["Unravelling the complex magnetosphere of the B star HD 133880 via wideband observation of coherent radio emission"](https://doi.org/10.1093%2Fmnras%2Fstaa2499). *Monthly Notices of the Royal Astronomical Society*. **499** (1): 702–709. [arXiv](/source/ArXiv_(identifier)):[2008.07170](https://arxiv.org/abs/2008.07170). [Bibcode](/source/Bibcode_(identifier)):[2020MNRAS.499..702D](https://ui.adsabs.harvard.edu/abs/2020MNRAS.499..702D). [doi](/source/Doi_(identifier)):[10.1093/mnras/staa2499](https://doi.org/10.1093%2Fmnras%2Fstaa2499).

1. **[^](#cite_ref-Waelkens1985_11-0)** Waelkens, C. (July 1985). "Photometric variations and period determination of eight southern CP stars". *Astronomy and Astrophysics Supplement Series*. **61**: 127–139. [Bibcode](/source/Bibcode_(identifier)):[1985A&AS...61..127W](https://ui.adsabs.harvard.edu/abs/1985A&AS...61..127W).

1. **[^](#cite_ref-Kholopov1987_12-0)** Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V. (August 1987). ["The 68th Name-List of Variable Stars"](https://ibvs.konkoly.hu/pub/ibvs/3001/3058.pdf) (PDF). *Information Bulletin on Variable Stars*. **3058** (1): 1. [Bibcode](/source/Bibcode_(identifier)):[1987IBVS.3058....1K](https://ui.adsabs.harvard.edu/abs/1987IBVS.3058....1K). Retrieved 23 January 2023.

1. ^ [***a***](#cite_ref-Das2018_13-0) [***b***](#cite_ref-Das2018_13-1) Das, Barnali; Chandra, Poonam; Wade, Gregg A. (February 2018). ["Discovery of electron cyclotron MASER emission from the magnetic Bp star HD 133880 with the Giant Metrewave Radio Telescope"](https://doi.org/10.1093%2Fmnrasl%2Fslx193). *Monthly Notices of the Royal Astronomical Society: Letters*. **474** (1): L61-L65. [arXiv](/source/ArXiv_(identifier)):[1711.09836](https://arxiv.org/abs/1711.09836). [Bibcode](/source/Bibcode_(identifier)):[2018MNRAS.474L..61D](https://ui.adsabs.harvard.edu/abs/2018MNRAS.474L..61D). [doi](/source/Doi_(identifier)):[10.1093/mnrasl/slx193](https://doi.org/10.1093%2Fmnrasl%2Fslx193).

1. **[^](#cite_ref-Landstreet1990_14-0)** Landstreet, J. D. (March 1990). ["The Very Strong and Unusual Magnetic Field of the BP Silicon Star HD 133880"](https://doi.org/10.1086%2F185680). *Astrophysical Journal Letters*. **352**: L5. [Bibcode](/source/Bibcode_(identifier)):[1990ApJ...352L...5L](https://ui.adsabs.harvard.edu/abs/1990ApJ...352L...5L). [doi](/source/Doi_(identifier)):[10.1086/185680](https://doi.org/10.1086%2F185680).

1. **[^](#cite_ref-Kochukhov2017_15-0)** Kochukhov, O.; Silvester, J.; Bailey, J. D.; Landstreet, J. D.; Wade, G. A. (September 2017). ["Magnetic field topology and chemical abundance distributions of the young, rapidly rotating, chemically peculiar star HR 5624"](https://doi.org/10.1051%2F0004-6361%2F201730919). *Astronomy and Astrophysics*. **605**: A13. [arXiv](/source/ArXiv_(identifier)):[1705.04966](https://arxiv.org/abs/1705.04966). [Bibcode](/source/Bibcode_(identifier)):[2017A&A...605A..13K](https://ui.adsabs.harvard.edu/abs/2017A&A...605A..13K). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201730919](https://doi.org/10.1051%2F0004-6361%2F201730919).

1. **[^](#cite_ref-Lim1996_16-0)** Lim, Jeremy; Drake, Stephen A.; Linsky, Jeffrey L. (1996). "Rotation Modulation of Radio Emissionfrom the Magnetic Bp Star HR 5624". *Radio Emission from the Stars and the Sun ASP Conference Series*. **93**: 324. [Bibcode](/source/Bibcode_(identifier)):[1996ASPC...93..324L](https://ui.adsabs.harvard.edu/abs/1996ASPC...93..324L).

1. **[^](#cite_ref-Leto2016_17-0)** Leto, P.; Trigilio, C.; Buemi, C. S.; Umana, G.; Ingallinera, A.; Cerrigone, L. (June 2016). ["3D modelling of stellar auroral radio emission"](https://doi.org/10.1093%2Fmnras%2Fstw639). *Monthly Notices of the Royal Astronomical Society*. **459** (2): 1159–1169. [arXiv](/source/ArXiv_(identifier)):[1603.02423](https://arxiv.org/abs/1603.02423). [Bibcode](/source/Bibcode_(identifier)):[2016MNRAS.459.1159L](https://ui.adsabs.harvard.edu/abs/2016MNRAS.459.1159L). [doi](/source/Doi_(identifier)):[10.1093/mnras/stw639](https://doi.org/10.1093%2Fmnras%2Fstw639).

v t e Constellation of Lupus List of stars in Lupus Lupus in Chinese astronomy Stars Bayer α (Uridim) β γ δ ε ζ η θ ι κ λ μ ν1 ν2 ξ ο π ρ σ τ1 τ2 υ φ1 φ2 χ ψ1 ψ2 ω Flamsteed 1 (i) 2 (f) Variable RU EX GG GQ HR II IL IM KT (d) V407 V462 HR 5362 5364 5401 5651 (e) 5724 (k) 5825 (g) 5943 5967 HD 134004 135344 136164 141943 142527 143811 Other Gliese 588 HIP 70849 Lupus-TR-3 SSSPM J1549−3544 WASP-132 Exoplanets GQ Lupi b HIP 70849 b Lupus-TR-3b WASP-178b Star clusters NGC 5749 NGC 5822 NGC 5824 NGC 5927 NGC 5986 Nebulae IC 4406 NGC 5882 Galaxies IC 4444 NGC 5530 NGC 5643 Astronomical events SN 1006 Category

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Adapted from the Wikipedia article [HD 133880](https://en.wikipedia.org/wiki/HD_133880) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/HD_133880?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.