# Delta Lupi

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Star in the constellation of Lupus

δ Lupi Location of δ Lupi (circled) Observation data Epoch J2000.0 Equinox J2000.0 Constellation Lupus Right ascension 15h 21m 22.32168s[1] Declination −40° 38′ 51.0738″[1] Apparent magnitude (V) 3.20 - 3.24[2] Characteristics Spectral type B1.5 IV[3] U−B color index −0.910[4] B−V color index −0.224[4] Variable type β Cep[5][2] Astrometry Radial velocity (Rv) +0.2[6] km/s Proper motion (μ) RA: −19.49[1] mas/yr Dec.: −25.29[1] mas/yr Parallax (π) 3.69±0.54 mas[1] Distance approx. 900 ly (approx. 270 pc) Absolute magnitude (MV) −3.1[7] Details Mass 11.9±0.2[8] M☉ Radius 6.1[9] R☉ Luminosity 10,000[8] L☉ Surface gravity (log g) 3.86[8] cgs Temperature 22,908[8] K Metallicity [Fe/H] −0.25±0.11[10] dex Rotational velocity (v sin i) 230[11] km/s Age 15.4±1.3[8] Myr Other designations CD−40°9538, FK5 1402, HD 136298, HIP 75141, HR 5695, SAO 225691, UBV 13201[12] Database references SIMBAD data

**Delta Lupi** (δ Lupi, δ Lup) is a [star](/source/Star) in the southern [circumpolar constellation](/source/Circumpolar_constellation) of [Lupus](/source/Lupus_(constellation)). In traditional [Chinese](/source/Chinese_language) astronomy, it is "the 2nd (star) of the Cavalry Officer" (騎官二). With an [apparent visual magnitude](/source/Apparent_visual_magnitude) of 3.2, it is the fourth-brightest star in the constellation. The distance to this star has been measured using the [parallax](/source/Parallax) technique, yielding an estimate of roughly 900 [light-years](/source/Light-year) with a 15% [margin of error](/source/Margin_of_error).[1]

A [light curve](/source/Light_curve) for Delta Lupi, plotted from *[TESS](/source/Transiting_Exoplanet_Survey_Satellite)* data[13]

The [spectrum](/source/Stellar_spectrum) of this star matches a [stellar classification](/source/Stellar_classification) of B1.5 IV,[3] which indicates this star has entered the [subgiant](/source/Subgiant_star) stage and is in the process of [evolving](/source/Stellar_evolution) into a [giant star](/source/Giant_star). It is radiating around 10,000 times the luminosity of the [Sun](/source/Sun) from its outer atmosphere at an effective temperature of 23,000 [K](/source/Kelvin), giving it a blue-white hue. This star has nearly 12 times the mass of the Sun and is roughly 15 million years old.[8]

Delta Lupi is a [Beta Cephei](/source/Beta_Cephei_variable) [variable star](/source/Variable_star) that undergoes periodic pulsations. It has a single period of variability lasting 0.1655 days, or six cycles per day.[5] This is a [proper motion](/source/Proper_motion) member of the Upper Centaurus–Lupus sub-group in the [Scorpius–Centaurus](/source/Scorpius%E2%80%93Centaurus_association) [OB association](/source/Stellar_association), the nearest such co-moving association of massive stars to the Sun.[7]

## See also

- [Traditional Chinese star names#Lupus](/source/Traditional_Chinese_star_names#Lupus)

## References

1. ^ [***a***](#cite_ref-aaa474_2_653_1-0) [***b***](#cite_ref-aaa474_2_653_1-1) [***c***](#cite_ref-aaa474_2_653_1-2) [***d***](#cite_ref-aaa474_2_653_1-3) [***e***](#cite_ref-aaa474_2_653_1-4) [***f***](#cite_ref-aaa474_2_653_1-5) 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-gcvs_2-0) [***b***](#cite_ref-gcvs_2-1) Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". *Astronomy Reports*. **61** (1): 80–88. [Bibcode](/source/Bibcode_(identifier)):[2017ARep...61...80S](https://ui.adsabs.harvard.edu/abs/2017ARep...61...80S). [doi](/source/Doi_(identifier)):[10.1134/S1063772917010085](https://doi.org/10.1134%2FS1063772917010085). [ISSN](/source/ISSN_(identifier)) [1063-7729](https://search.worldcat.org/issn/1063-7729). [S2CID](/source/S2CID_(identifier)) [255195566](https://api.semanticscholar.org/CorpusID:255195566).

1. ^ [***a***](#cite_ref-apj157_313_3-0) [***b***](#cite_ref-apj157_313_3-1) Hiltner, W. A.; Garrison, R. F.; Schild, R. E. (July 1969), "MK spectral types for bright southern OB stars", *Astrophysical Journal*, **157**: 313, [Bibcode](/source/Bibcode_(identifier)):[1969ApJ...157..313H](https://ui.adsabs.harvard.edu/abs/1969ApJ...157..313H), [doi](/source/Doi_(identifier)):[10.1086/150069](https://doi.org/10.1086%2F150069)

1. ^ [***a***](#cite_ref-apjs15_459_4-0) [***b***](#cite_ref-apjs15_459_4-1) Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", *Astrophysical Journal Supplement*, **15**: 459, [Bibcode](/source/Bibcode_(identifier)):[1968ApJS...15..459G](https://ui.adsabs.harvard.edu/abs/1968ApJS...15..459G), [doi](/source/Doi_(identifier)):[10.1086/190168](https://doi.org/10.1086%2F190168)

1. ^ [***a***](#cite_ref-mnras377_2_645_5-0) [***b***](#cite_ref-mnras377_2_645_5-1) Smolec, R.; Moskalik, P. (May 2007), "Amplitude saturation in β Cephei models", *Monthly Notices of the Royal Astronomical Society*, **377** (2): 645–656, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0702406](https://arxiv.org/abs/astro-ph/0702406), [Bibcode](/source/Bibcode_(identifier)):[2007MNRAS.377..645S](https://ui.adsabs.harvard.edu/abs/2007MNRAS.377..645S), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2007.11620.x](https://doi.org/10.1111%2Fj.1365-2966.2007.11620.x), [S2CID](/source/S2CID_(identifier)) [17908442](https://api.semanticscholar.org/CorpusID:17908442)

1. **[^](#cite_ref-rgcrv_6-0)** Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). *Determination of Radial Velocities and their Applications*. IAU Symposium no. 30. Vol. 30. University of Toronto: [International Astronomical Union](/source/International_Astronomical_Union). p. 57. [Bibcode](/source/Bibcode_(identifier)):[1967IAUS...30...57E](https://ui.adsabs.harvard.edu/abs/1967IAUS...30...57E).

1. ^ [***a***](#cite_ref-aaa216_1_44_7-0) [***b***](#cite_ref-aaa216_1_44_7-1) de Geus, E. J.; de Zeeuw, P. T.; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", *Astronomy and Astrophysics*, **216** (1–2): 44–61, [Bibcode](/source/Bibcode_(identifier)):[1989A&A...216...44D](https://ui.adsabs.harvard.edu/abs/1989A&A...216...44D)

1. ^ [***a***](#cite_ref-mnras410_1_190_8-0) [***b***](#cite_ref-mnras410_1_190_8-1) [***c***](#cite_ref-mnras410_1_190_8-2) [***d***](#cite_ref-mnras410_1_190_8-3) [***e***](#cite_ref-mnras410_1_190_8-4) [***f***](#cite_ref-mnras410_1_190_8-5) Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (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-mnras189_601_9-0)** Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", *Monthly Notices of the Royal Astronomical Society*, **189** (3): 601–605, [Bibcode](/source/Bibcode_(identifier)):[1979MNRAS.189..601U](https://ui.adsabs.harvard.edu/abs/1979MNRAS.189..601U), [doi](/source/Doi_(identifier)):[10.1093/mnras/189.3.601](https://doi.org/10.1093%2Fmnras%2F189.3.601)

1. **[^](#cite_ref-aaa433_2_659_10-0)** Niemczura, E.; Daszyńska-Daszkiewicz, J. (April 2005), "Metallicities of the β Cephei stars from low-resolution ultraviolet spectra", *Astronomy and Astrophysics*, **433** (2): 659–669, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0410440](https://arxiv.org/abs/astro-ph/0410440), [Bibcode](/source/Bibcode_(identifier)):[2005A&A...433..659N](https://ui.adsabs.harvard.edu/abs/2005A&A...433..659N), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20040396](https://doi.org/10.1051%2F0004-6361%3A20040396), [S2CID](/source/S2CID_(identifier)) [14295631](https://api.semanticscholar.org/CorpusID:14295631). Note: value taken from [m/H].

1. **[^](#cite_ref-coapa239_1_11-0)** Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". *Contributi Osservatorio Astronomico di Padova in Asiago*. **239** (1): 1. [Bibcode](/source/Bibcode_(identifier)):[1970CoAsi.239....1B](https://ui.adsabs.harvard.edu/abs/1970CoAsi.239....1B).

1. **[^](#cite_ref-SIMBAD_12-0)** ["del Lup"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+Lup). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2007-01-18.

1. **[^](#cite_ref-MAST_13-0)** ["MAST: Barbara A. Mikulski Archive for Space Telescopes"](https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html). Space Telescope Science Institute. Retrieved 11 December 2022.

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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