# Psi2 Lupi

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Star in the constellation Lupus

Psi2 Lupi Location of ψ2 Lupi (circled in red) Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) Constellation Lupus Right ascension 15h 42m 41.02206s[1] Declination −34° 42′ 37.4617″[1] Apparent magnitude (V) 4.75[2] Characteristics Spectral type B5 V[3] U−B color index −0.570[2] B−V color index −0.146[2] Variable type Microvariable[3] Astrometry Radial velocity (Rv) +3.9±2.8[4] km/s Proper motion (μ) RA: −21.37[1] mas/yr Dec.: −29.98[1] mas/yr Parallax (π) 8.97±0.27 mas[1] Distance 360 ± 10 ly (111 ± 3 pc) Absolute magnitude (MV) −1.44[2] Orbit[5] Period (P) 12.26 d Eccentricity (e) 0.19 Periastron epoch (T) 2438252.97 ± 10.0 JD Argument of periastron (ω) (secondary) 82.8° Semi-amplitude (K1) (primary) 63.3 km/s Semi-amplitude (K2) (secondary) 66.4 km/s Details Surface gravity (log g) 4.29[3] cgs Temperature 15,135[3] K Other designations ψ2 Lup, 4 Lup, CD−34°10494, HD 140008, HIP 76945, HR 5839, SAO 206889[6] Database references SIMBAD data

**Psi2 Lupi** (**ψ2 Lup**) is a [triple star](/source/Triple_star)[7] system in the [constellation](/source/Constellation) [Lupus](/source/Lupus_(constellation)). It is visible to the naked eye with an [apparent magnitude](/source/Apparent_magnitude) of 4.75.[2] Based upon an annual [parallax shift](/source/Stellar_parallax) of 8.97[1] [mas](/source/Milliarcsecond) as seen from Earth, it is located around 360 [light years](/source/Light_year) from the [Sun](/source/Sun). At that distance, the visual magnitude is diminished by an [extinction factor](/source/Extinction_(astronomy)) of 0.016±0.009 due to [interstellar dust](/source/Interstellar_dust). This system is a member of the Upper Centaurus–Lupus subgroup of the [Scorpius–Centaurus association](/source/Scorpius%E2%80%93Centaurus_association).[8]

The inner pair of stars in this system form a double-lined [spectroscopic binary](/source/Spectroscopic_binary) with an [orbital period](/source/Orbital_period) of 12.26 days and an [eccentricity](/source/Orbital_eccentricity) of 0.19. The two components are described as similar in appearance.[5] They have the [spectrum](/source/Stellar_spectrum) of a [B-type main sequence star](/source/B-type_main_sequence_star) with a [stellar classification](/source/Stellar_classification) of B5 V.[3] The luminosity has a micro-variability with a [frequency](/source/Frequency) of 0.94483 cycles per day and an [amplitude](/source/Amplitude) of 0.0067 in magnitude.[3] The third component is a magnitude 10 star at an [angular separation](/source/Angular_separation) of 0.51 [arc seconds](/source/Arc_second).[7]

## See also

- [ψ1 Lupi](/source/Psi1_Lupi)

## References

1. ^ [***a***](#cite_ref-vanLeeuwen2007_1-0) [***b***](#cite_ref-vanLeeuwen2007_1-1) [***c***](#cite_ref-vanLeeuwen2007_1-2) [***d***](#cite_ref-vanLeeuwen2007_1-3) [***e***](#cite_ref-vanLeeuwen2007_1-4) [***f***](#cite_ref-vanLeeuwen2007_1-5) van Leeuwen, F. (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-GutierrezMoreno1968_2-0) [***b***](#cite_ref-GutierrezMoreno1968_2-1) [***c***](#cite_ref-GutierrezMoreno1968_2-2) [***d***](#cite_ref-GutierrezMoreno1968_2-3) [***e***](#cite_ref-GutierrezMoreno1968_2-4) 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-MolendaZakowicz2005_3-0) [***b***](#cite_ref-MolendaZakowicz2005_3-1) [***c***](#cite_ref-MolendaZakowicz2005_3-2) [***d***](#cite_ref-MolendaZakowicz2005_3-3) [***e***](#cite_ref-MolendaZakowicz2005_3-4) [***f***](#cite_ref-MolendaZakowicz2005_3-5) Molenda-Zakowicz, J.; Polubek, G. (December 2005), "New beta Cephei and SPB Stars Discovered in Hipparcos Photometry", *Acta Astronomica*, **55**: 375–388, [Bibcode](/source/Bibcode_(identifier)):[2005AcA....55..375M](https://ui.adsabs.harvard.edu/abs/2005AcA....55..375M).

1. **[^](#cite_ref-deBruijne2012_4-0)** de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", *Astronomy & Astrophysics*, **546**: 14, [arXiv](/source/ArXiv_(identifier)):[1208.3048](https://arxiv.org/abs/1208.3048), [Bibcode](/source/Bibcode_(identifier)):[2012A&A...546A..61D](https://ui.adsabs.harvard.edu/abs/2012A&A...546A..61D), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201219219](https://doi.org/10.1051%2F0004-6361%2F201219219), [S2CID](/source/S2CID_(identifier)) [59451347](https://api.semanticscholar.org/CorpusID:59451347), A61.

1. ^ [***a***](#cite_ref-Pourbaix2004_5-0) [***b***](#cite_ref-Pourbaix2004_5-1) Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", *Astronomy & Astrophysics*, **424** (2): 727–732, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0406573](https://arxiv.org/abs/astro-ph/0406573), [Bibcode](/source/Bibcode_(identifier)):[2004A&A...424..727P](https://ui.adsabs.harvard.edu/abs/2004A&A...424..727P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20041213](https://doi.org/10.1051%2F0004-6361%3A20041213), [S2CID](/source/S2CID_(identifier)) [119387088](https://api.semanticscholar.org/CorpusID:119387088).

1. **[^](#cite_ref-SIMBAD_6-0)** ["psi02 Lup"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=psi02+Lup). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2017-03-10.{{[cite web](https://en.wikipedia.org/wiki/Template:Cite_web)}}: CS1 maint: postscript ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_postscript))

1. ^ [***a***](#cite_ref-Eggleton2008_7-0) [***b***](#cite_ref-Eggleton2008_7-1) Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", *[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*, **389** (2): 869–879, [arXiv](/source/ArXiv_(identifier)):[0806.2878](https://arxiv.org/abs/0806.2878), [Bibcode](/source/Bibcode_(identifier)):[2008MNRAS.389..869E](https://ui.adsabs.harvard.edu/abs/2008MNRAS.389..869E), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2008.13596.x](https://doi.org/10.1111%2Fj.1365-2966.2008.13596.x), [S2CID](/source/S2CID_(identifier)) [14878976](https://api.semanticscholar.org/CorpusID:14878976).

1. **[^](#cite_ref-Chen2012_8-0)** Chen, Christine H.; et al. (September 2012), "A Spitzer MIPS Study of 2.5–2.0 M☉ Stars in Scorpius–Centaurus", *The Astrophysical Journal*, **756** (2): 24, [arXiv](/source/ArXiv_(identifier)):[1207.3415](https://arxiv.org/abs/1207.3415), [Bibcode](/source/Bibcode_(identifier)):[2012ApJ...756..133C](https://ui.adsabs.harvard.edu/abs/2012ApJ...756..133C), [doi](/source/Doi_(identifier)):[10.1088/0004-637X/756/2/133](https://doi.org/10.1088%2F0004-637X%2F756%2F2%2F133), [S2CID](/source/S2CID_(identifier)) [119278056](https://api.semanticscholar.org/CorpusID:119278056), 133.

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 [Psi2 Lupi](https://en.wikipedia.org/wiki/Psi2_Lupi) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Psi2_Lupi?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.