# 48 Librae

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/48_Librae
> Markdown URL: https://mediated.wiki/source/48_Librae.md
> Source: https://en.wikipedia.org/wiki/48_Librae
> Source revision: 1352055714
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Star in the constellation Libra

48 Librae Location of 48 Librae (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Libra[1] Right ascension 15h 58m 11.36869s[2] Declination −14° 16′ 45.6894″[2] Apparent magnitude (V) 4.95[1] Characteristics Evolutionary stage main sequence[3] Spectral type B3 Vsh[4][5] B−V color index −0.08±0.11[1] Variable type γ Cas[6] Astrometry Radial velocity (Rv) −7.5±1.8[7] km/s Proper motion (μ) RA: −12.44[2] mas/yr Dec.: −16.73[2] mas/yr Parallax (π) 6.97±0.24 mas[2] Distance 470 ± 20 ly (143 ± 5 pc) Absolute magnitude (MV) −0.83[1] Details Mass 6.07[5] M☉ Radius 4.12[5] R☉ Luminosity 1,100[5] L☉ Surface gravity (log g) 3.71±0.04[8] cgs Temperature 18,000±180[8] K Rotation 9.6 hours[9] Rotational velocity (v sin i) 400[5] km/s Age 10[10] Myr Other designations 48 Lib, FX Lib, AAVSO 1552-14, BD−13°4302, FK5 1417, HD 142983, HIP 78207, HR 5941, SAO 159607[11] Database references SIMBAD data

**48 Librae** is a single[5] [shell star](/source/Shell_star) in the [constellation](/source/Constellation) [Libra](/source/Libra_(constellation)). It is a [variable star](/source/Variable_star) with the [designation](/source/Variable_star_designation) FX Lib, ranging in magnitude from 4.74 to 4.96.[6] Based upon an annual [parallax shift](/source/Stellar_parallax) of 6.97±0.24 [mas](/source/Milliarcsecond) as seen from Earth's orbit, it is located approximately 470 [light years](/source/Light_year) from the Sun. It is a candidate member of the Upper Scorpius group of the [Scorpius–Centaurus association](/source/Scorpius%E2%80%93Centaurus_association), with the former having an age of about 11 million years.[12]

A broad-band optical [light curve](/source/Light_curve) for FX Librae, adapted from Ozuyar *et al.* (2018)[9]

This is a [main sequence](/source/B-type_main-sequence_star) [Be star](/source/Be_star) with a [stellar classification](/source/Stellar_classification) of B3 Vsh,[4] although it has been variously classed as B3V, B5IIIp shell He-n, B6p shell, B4III, B3IV:e-shell, and B3 shell by different sources. As is the norm for a shell star, it is spinning very rapidly with a [projected rotational velocity](/source/Projected_rotational_velocity) of 400 km/s − matching or exceeding 80% of the [critical velocity](/source/Break-up_velocity).[5] This is giving the star a pronounced [oblate shape](/source/Oblate_spheroid) with an [equatorial bulge](/source/Equatorial_bulge) that is estimated to be 43% larger than the polar radius.[13] It has six times the [mass of the Sun](/source/Mass_of_the_Sun) and four times the [Sun's radius](/source/Sun's_radius). The star is radiating 1,100[5] times the [Sun's luminosity](/source/Sun's_luminosity) from its [photosphere](/source/Photosphere) at an [effective temperature](/source/Effective_temperature) of 18,000 K.[8]

The surrounding gaseous disk stretches out to at least 15[14] times the star's radius and is nearly aligned with the line of sight from the Earth, having an estimated [inclination](/source/Inclination) of 85°±3°.[5] Some time between 1931 and 1935, the disk became active and has remained so since that time, becoming the subject of multiple studies.[15] The unusual asymmetry in its [emission lines](/source/Emission_line) have led to it being misclassified as a [supergiant](/source/Supergiant) of type B8 Ia/Ib by [SIMBAD](/source/SIMBAD) and others. This asymmetry displays quasi-periodic behavior of the type found in about a third of all Be stars, with a period of about 10 to 17 years. This variation may arise from the precession of a one-armed density wave in the disk.[5]

The [Bayer designation](/source/Bayer_designation) [Phi Scorpii](/source/Phi_Scorpii) has been associated with this star. No star is found at the position marked φ Scorpii in [Johann Bayer](/source/Johann_Bayer)'s [Uranometria](/source/Uranometria).[16] The closest stars to that position are 48 and 49 Librae; 48 Librae is clearly shown but not given a designation while no star is shown at the position of 49 Librae. In his Uranographia [Bode](/source/Johann_Elert_Bode) assigned the designation φ Scorpii to the star now known as 49 Librae.[17] The designation is no longer in use.[18]

## 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](/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=78207&-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-vanLeeuwen2007_2-0) [***b***](#cite_ref-vanLeeuwen2007_2-1) [***c***](#cite_ref-vanLeeuwen2007_2-2) [***d***](#cite_ref-vanLeeuwen2007_2-3) [***e***](#cite_ref-vanLeeuwen2007_2-4) 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. **[^](#cite_ref-dr3_3-0)** 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%3D6263223955904774656%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-rivinius2013_4-0) [***b***](#cite_ref-rivinius2013_4-1) Rivinius, Thomas; et al. (2013), "Classical Be stars. Rapidly rotating B stars with viscous Keplerian decretion disks", *The Astronomy and Astrophysics Review*, **21**: 69, [arXiv](/source/ArXiv_(identifier)):[1310.3962](https://arxiv.org/abs/1310.3962), [Bibcode](/source/Bibcode_(identifier)):[2013A&ARv..21...69R](https://ui.adsabs.harvard.edu/abs/2013A&ARv..21...69R), [doi](/source/Doi_(identifier)):[10.1007/s00159-013-0069-0](https://doi.org/10.1007%2Fs00159-013-0069-0), [S2CID](/source/S2CID_(identifier)) [118652497](https://api.semanticscholar.org/CorpusID:118652497).

1. ^ [***a***](#cite_ref-Silaj2016_5-0) [***b***](#cite_ref-Silaj2016_5-1) [***c***](#cite_ref-Silaj2016_5-2) [***d***](#cite_ref-Silaj2016_5-3) [***e***](#cite_ref-Silaj2016_5-4) [***f***](#cite_ref-Silaj2016_5-5) [***g***](#cite_ref-Silaj2016_5-6) [***h***](#cite_ref-Silaj2016_5-7) [***i***](#cite_ref-Silaj2016_5-8) [***j***](#cite_ref-Silaj2016_5-9) Silaj, J.; et al. (July 2016), "Investigating the Circumstellar Disk of the Be Shell Star 48 Librae", *The Astrophysical Journal*, **826** (1): 11, [arXiv](/source/ArXiv_(identifier)):[1608.00943](https://arxiv.org/abs/1608.00943), [Bibcode](/source/Bibcode_(identifier)):[2016ApJ...826...81S](https://ui.adsabs.harvard.edu/abs/2016ApJ...826...81S), [doi](/source/Doi_(identifier)):[10.3847/0004-637X/826/1/81](https://doi.org/10.3847%2F0004-637X%2F826%2F1%2F81), [S2CID](/source/S2CID_(identifier)) [119112873](https://api.semanticscholar.org/CorpusID:119112873), 81.

1. ^ [***a***](#cite_ref-Samus2017_6-0) [***b***](#cite_ref-Samus2017_6-1) Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", *Astronomy Reports*, GCVS 5.1, **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), [S2CID](/source/S2CID_(identifier)) [125853869](https://api.semanticscholar.org/CorpusID:125853869).

1. **[^](#cite_ref-deBruijne2012_7-0)** 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-arcos2018_8-0) [***b***](#cite_ref-arcos2018_8-1) [***c***](#cite_ref-arcos2018_8-2) Arcos, C.; Kanaan, S.; Chávez, J.; Vanzi, L.; Araya, I.; Curé, M. (2018), "Stellar parameters and H α line profile variability of be stars in the BeSOS survey", *Monthly Notices of the Royal Astronomical Society*, **474** (4): 5287, [arXiv](/source/ArXiv_(identifier)):[1711.08675](https://arxiv.org/abs/1711.08675), [Bibcode](/source/Bibcode_(identifier)):[2018MNRAS.474.5287A](https://ui.adsabs.harvard.edu/abs/2018MNRAS.474.5287A), [doi](/source/Doi_(identifier)):[10.1093/mnras/stx3075](https://doi.org/10.1093%2Fmnras%2Fstx3075).

1. ^ [***a***](#cite_ref-Ozuyar2018_9-0) [***b***](#cite_ref-Ozuyar2018_9-1) Ozuyar, D.; Caliskan, S.; Stevens, I. R.; Elmasli, A. (November 2018). "Photometric and spectroscopic variability of the Be star 48 Lib: The relation between photometric variations and rotation". *Publications of the Astronomical Society of Australia*. **35** e034. [Bibcode](/source/Bibcode_(identifier)):[2018PASA...35...34O](https://ui.adsabs.harvard.edu/abs/2018PASA...35...34O). [doi](/source/Doi_(identifier)):[10.1017/pasa.2018.38](https://doi.org/10.1017%2Fpasa.2018.38). [S2CID](/source/S2CID_(identifier)) [126232532](https://api.semanticscholar.org/CorpusID:126232532).

1. **[^](#cite_ref-squicciarini2025_10-0)** Squicciarini, V.; Mazoyer, J.; Lagrange, A. -M.; Chomez, A.; Delorme, P.; Flasseur, O.; Kiefer, F.; Bergeon, S.; Albert, D.; Meunier, N. (2025). "The COBREX archival survey: Improved constraints on the occurrence rate of wide-orbit substellar companions: I. A uniform re-analysis of 400 stars from the GPIES survey". *Astronomy and Astrophysics*. **693**. [arXiv](/source/ArXiv_(identifier)):[2411.06157](https://arxiv.org/abs/2411.06157). [Bibcode](/source/Bibcode_(identifier)):[2025A&A...693A..54S](https://ui.adsabs.harvard.edu/abs/2025A&A...693A..54S). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202452310](https://doi.org/10.1051%2F0004-6361%2F202452310).

1. **[^](#cite_ref-SIMBAD_11-0)** ["48 Lib"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=48+Lib). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2018-03-04.

1. **[^](#cite_ref-Condell2015_12-0)** Jang-Condell, Hannah; et al. (August 2015), "Spitzer IRS Spectra of Debris Disks in the Scorpius–Centaurus OB Association", *The Astrophysical Journal*, **808** (2): 19, [arXiv](/source/ArXiv_(identifier)):[1506.05428](https://arxiv.org/abs/1506.05428), [Bibcode](/source/Bibcode_(identifier)):[2015ApJ...808..167J](https://ui.adsabs.harvard.edu/abs/2015ApJ...808..167J), [doi](/source/Doi_(identifier)):[10.1088/0004-637X/808/2/167](https://doi.org/10.1088%2F0004-637X%2F808%2F2%2F167), [S2CID](/source/S2CID_(identifier)) [118549483](https://api.semanticscholar.org/CorpusID:118549483), 167.

1. **[^](#cite_ref-vanBelle2012_13-0)** van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", *The Astronomy and Astrophysics Review*, **20** (1) 51, [arXiv](/source/ArXiv_(identifier)):[1204.2572](https://arxiv.org/abs/1204.2572), [Bibcode](/source/Bibcode_(identifier)):[2012A&ARv..20...51V](https://ui.adsabs.harvard.edu/abs/2012A&ARv..20...51V), [doi](/source/Doi_(identifier)):[10.1007/s00159-012-0051-2](https://doi.org/10.1007%2Fs00159-012-0051-2), [S2CID](/source/S2CID_(identifier)) [119273474](https://api.semanticscholar.org/CorpusID:119273474).

1. **[^](#cite_ref-Stefl2012_14-0)** Štefl, S.; et al. (April 2012), "New activity in the large circumstellar disk of the Be-shell star 48 Librae", *Astronomy & Astrophysics*, **540**: 12, [arXiv](/source/ArXiv_(identifier)):[1202.4523](https://arxiv.org/abs/1202.4523), [Bibcode](/source/Bibcode_(identifier)):[2012A&A...540A..76S](https://ui.adsabs.harvard.edu/abs/2012A&A...540A..76S), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201118054](https://doi.org/10.1051%2F0004-6361%2F201118054), [S2CID](/source/S2CID_(identifier)) [54663995](https://api.semanticscholar.org/CorpusID:54663995), A76

1. **[^](#cite_ref-Faraggiana1969_15-0)** Faraggiana, R. (June 1969), "A study of 48 Librae in the period 1950 - 1962", *Astronomy and Astrophysics*, **2**: 162, [Bibcode](/source/Bibcode_(identifier)):[1969A&A.....2..162F](https://ui.adsabs.harvard.edu/abs/1969A&A.....2..162F).

1. **[^](#cite_ref-bayer_16-0)** Bayer, Johann; Mair, Alexander (1603). [*Uranometria*](https://books.google.com/books?id=5NrCIF5mnysC&dq=bayer+uranometria&pg=IA1) (in Latin). Excvdit Christophorvs Mangvs. Retrieved 2025-11-10.

1. **[^](#cite_ref-startales_17-0)** [Ian Ridpath](/source/Ian_Ridpath). ["Scorpius"](http://www.ianridpath.com/startales/scorpius.html). *Star Tales*. Retrieved 2025-09-10.

1. **[^](#cite_ref-kaler-sco_18-0)** ["Chi and Psi Scorpii"](http://stars.astro.illinois.edu/sow/chisco.html), *stars.astro.illinois.edu*, retrieved 2025-07-13.

v t e Constellation of Libra List of stars in Libra Libra in Chinese astronomy Stars Bayer α1 α2 (Zubenelgenubi) β (Zubeneschamali) γ (Zubenelhakrabi) δ ε ζ1 ζ2 ζ3 ζ4 η θ ι1 ι2 κ λ μ ν ξ1 ξ2 ο σ (Brachium) τ υ Flamsteed 2 3 4 5 10 11 12 16 17 18 22 23 26 28 30 36 37 41 42 47 48 49 50 Variable HN HO KU KX HR 5504 5455 HD 133131 134439 134440 135485 137010 139139 140283 141569 141937 Other 2M1510 2MASS 1507−1627 CWISEP J1446−2317 HE 1523−0901 WASP-57 WISE 1534−1043 WISE 1541−2250 Exoplanets 23 Librae b c Gliese 581b c e HD 137010 b (unconfirmed) K2-315b WASP-189b Star clusters NGC 5897 Galaxies NGC 5597 5605 5716 5728 5792 5793 5861 5885 5890 5898 5915 5917 Other AP Librae IC 1059 IRAS 14348−1447 PKS 1510−089 PKS 1519−273 QSO B1524−136 RXC J1504.1−0248 BCG Category

---
Adapted from the Wikipedia article [48 Librae](https://en.wikipedia.org/wiki/48_Librae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/48_Librae?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.