# Psi1 Lupi

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Star in the constellation Lupus

ψ1 Lupi Location of ψ1 Lupi (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Lupus[1] Right ascension 15h 39m 45.97931s[2] Declination −34° 24′ 42.9073″[2] Apparent magnitude (V) +4.663[3] Characteristics Evolutionary stage red clump[3] Spectral type G8/K0 III[4] B−V color index 0.964±0.047[1] Astrometry Radial velocity (Rv) −23.1±0.8[1] km/s Proper motion (μ) RA: +6.123[2] mas/yr Dec.: −11.767[2] mas/yr Parallax (π) 15.7610±0.2700 mas[2] Distance 207 ± 4 ly (63 ± 1 pc) Absolute magnitude (MV) +0.24[5] Details Mass 2.42[5] M☉ Radius 10.76+0.20 −0.08[2] R☉ Luminosity 62.0±1.2[2] L☉ Surface gravity (log g) 3.28[6] cgs Temperature 4,939+17 −46[2] K Metallicity [Fe/H] −0.34[6] dex Other designations ψ1 Lup, 3 Lup, CD−33°10631, FK5 3237, HD 139521, HIP 76705, HR 5820, SAO 206843[7] Database references SIMBAD data

**Psi1 Lupi**, which is [Latinized](/source/Romanization_of_Greek) from ψ1 Lupi, is a single[8] [star](/source/Star) in the southern [constellation](/source/Constellation) of [Lupus](/source/Lupus_(constellation)). It has a yellow-white hue and is faintly visible to the naked eye with an [apparent visual magnitude](/source/Apparent_visual_magnitude) of +4.66.[3] The star is located at a distance of approximately 207 [light years](/source/Light_year) from the [Sun](/source/Sun) based on [parallax](/source/Stellar_parallax).[2] It is drifting closer with a [radial velocity](/source/Radial_velocity) of −23 km/s, and is predicted to come to within 36 light-years in 2.8 million years.[1]

This is an [evolved](/source/Stellar_evolution) [giant star](/source/Giant_star) with a [stellar classification](/source/Stellar_classification) of G8/K0 III.[4] With the hydrogen exhausted at its [core](/source/Stellar_core), the star has cooled and expanded to 11 times the [radius of the Sun](/source/Radius_of_the_Sun).[2] It is a [red clump](/source/Red_clump)[3] giant, which indicates it is on the [horizontal branch](/source/Horizontal_branch) and is generating energy through [core](/source/Stellar_core) [helium fusion](/source/Helium_fusion). The star has an estimated 2.4[5] times the [Sun's mass](/source/Sun's_mass) and is radiating 62 times the [luminosity of the Sun](/source/Luminosity_of_the_Sun) from its [photosphere](/source/Photosphere) at an [effective temperature](/source/Effective_temperature) of 4,939 K.[2]

The star is surrounded by a cold [circumstellar envelope](/source/Circumstellar_envelope), hinted at by the anomaly of the small observed power of the doublet Mg II emission at 2800 [angstrom](/source/Angstrom). The absorption cores on the peaks of the emission profiles Mg II k and h are mainly of interstellar origin and only partly due to self-absorption in the star's chromosphere.[9]

## See also

- [ψ2 Lupi](/source/Psi2_Lupi)

## References

1. ^ [***a***](#cite_ref-Anderson2012_1-0) [***b***](#cite_ref-Anderson2012_1-1) [***c***](#cite_ref-Anderson2012_1-2) [***d***](#cite_ref-Anderson2012_1-3) Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *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). [S2CID](/source/S2CID_(identifier)) [119257644](https://api.semanticscholar.org/CorpusID:119257644).

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) [***g***](#cite_ref-GaiaDR2_2-6) [***h***](#cite_ref-GaiaDR2_2-7) [***i***](#cite_ref-GaiaDR2_2-8) [***j***](#cite_ref-GaiaDR2_2-9) [***k***](#cite_ref-GaiaDR2_2-10) [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%206013425703029987712) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-alves2000_3-0) [***b***](#cite_ref-alves2000_3-1) [***c***](#cite_ref-alves2000_3-2) [***d***](#cite_ref-alves2000_3-3) Alves, David R. (2000). "K-Band Calibration of the Red Clump Luminosity". *The Astrophysical Journal*. **539** (2): 732–741. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0003329](https://arxiv.org/abs/astro-ph/0003329). [Bibcode](/source/Bibcode_(identifier)):[2000ApJ...539..732A](https://ui.adsabs.harvard.edu/abs/2000ApJ...539..732A). [doi](/source/Doi_(identifier)):[10.1086/309278](https://doi.org/10.1086%2F309278). [S2CID](/source/S2CID_(identifier)) [16673121](https://api.semanticscholar.org/CorpusID:16673121).

1. ^ [***a***](#cite_ref-houk_4-0) [***b***](#cite_ref-houk_4-1) Houk, N. (1982). *Michigan Catalogue of Two-dimensional Spectral Types for the HD stars*. Vol. 3. [Bibcode](/source/Bibcode_(identifier)):[1982mcts.book.....H](https://ui.adsabs.harvard.edu/abs/1982mcts.book.....H).

1. ^ [***a***](#cite_ref-aaa361_614_5-0) [***b***](#cite_ref-aaa361_614_5-1) [***c***](#cite_ref-aaa361_614_5-2) Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", *Astronomy and Astrophysics*, **361**: 614–628, [Bibcode](/source/Bibcode_(identifier)):[2000A&A...361..614P](https://ui.adsabs.harvard.edu/abs/2000A&A...361..614P)

1. ^ [***a***](#cite_ref-alves2015_6-0) [***b***](#cite_ref-alves2015_6-1) Adibekyan, V. Zh.; et al. (2015). ["Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars"](https://doi.org/10.1093%2Fmnras%2Fstv716). *Monthly Notices of the Royal Astronomical Society*. **450** (2): 1900. [arXiv](/source/ArXiv_(identifier)):[1503.08346](https://arxiv.org/abs/1503.08346). [Bibcode](/source/Bibcode_(identifier)):[2015MNRAS.450.1900A](https://ui.adsabs.harvard.edu/abs/2015MNRAS.450.1900A). [doi](/source/Doi_(identifier)):[10.1093/mnras/stv716](https://doi.org/10.1093%2Fmnras%2Fstv716). [S2CID](/source/S2CID_(identifier)) [58920318](https://api.semanticscholar.org/CorpusID:58920318).

1. **[^](#cite_ref-SIMBAD_7-0)** ["psi01 Lup"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=psi01+Lup). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2017-08-16.{{[cite web](https://en.wikipedia.org/wiki/Template:Cite_web)}}: CS1 maint: postscript ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_postscript))

1. **[^](#cite_ref-Eggleton2008_8-0)** Eggleton, P. P.; Tokovinin, A. A. (2008). ["A catalogue of multiplicity among bright stellar systems"](https://doi.org/10.1111%2Fj.1365-2966.2008.13596.x). *Monthly Notices of the Royal Astronomical Society*. **389** (2): 869. [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-Gurzadian_et_al._9-0)** Gurzadian, G. A.; et al. (1991). ["A cool giant with a circumstellar cloud"](https://zenodo.org/record/1232446). *Astrophysics and Space Science*. **176** (1): 61–68. [Bibcode](/source/Bibcode_(identifier)):[1991Ap&SS.176...61G](https://ui.adsabs.harvard.edu/abs/1991Ap&SS.176...61G). [doi](/source/Doi_(identifier)):[10.1007/BF00643077](https://doi.org/10.1007%2FBF00643077). [S2CID](/source/S2CID_(identifier)) [122673985](https://api.semanticscholar.org/CorpusID:122673985).

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 [Psi1 Lupi](https://en.wikipedia.org/wiki/Psi1_Lupi) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Psi1_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.