Xi Scorpii

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title: "Xi Scorpii" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["bayer-objects", "scorpius", "multiple-stars", "multiple-star-systems", "f-type-main-sequence-stars", "g-type-main-sequence-stars", "k-type-main-sequence-stars", "flamsteed-objects", "durchmusterung-objects", "gliese-and-gj-objects", "hipparcos-objects", "bright-star-catalogue-objects", "henry-draper-catalogue-objects"] description: "Star system" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Xi_Scorpii" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star system ::

| image = |image=Libra constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=ξ Scorpii |x=95|y=275 | caption = Location of ξ Scorpii (circled in red) |epoch=J2000 |constell=Scorpius |component1=ξ Sco ABC |ra1= |dec1= |appmag_v1=4.17 (5.16 / 4.87 / 7.30) |component2=Component D |ra2= |dec2= |appmag_v2=7.43 |component3=Component E |ra3= |dec3= |appmag_v3=7.81 |component1=ξ Sco ABC |class=F4(V) + F6(V) + G1V |b-v=+0.45 |u-b=+0.00 |component2=Components DE |class2=K1(V) + K1(V) |b-v2=+0.75 |u-b2=+0.315 |component1=ξ Sco ABC |radial_v= |prop_mo_ra=−63.2 |prop_mo_dec=−27.0 |parallax= |p_error= |parallax_footnote= |component1=Component D |radial_v= |prop_mo_ra=−61.607 |prop_mo_dec=−22.227 |parallax=35.8898 |p_error=0.0200 |parallax_footnote= |absmag_v=4.47 |component2=Component E |radial_v2= |prop_mo_ra2=−56.334 |prop_mo_dec2=−20.357 |parallax2=35.8718 |p_error2=0.0237 |parallax_footnote2= |absmag_v2=5.18{{cite journal | last1=Boro Saikia |first1=S. |last2=Marvin |first2=C. J. | last3=Jeffers |first3=S. V. |last4=Reiners |first4=Ansgar | last5=Cameron |first5=R. |last6=Marsden |first6=S. C. | last7=Petit |first7=P. |last8=Warnecke |first8=J. | last9=Yadav |first9=A. P. |last10=Teske |first10=J. K. | last11=Shectman |first11=S. A. |last12=Crane |first12=J. D. | last13=Thompson |first13=I. |last14=Keiser |first14=S. | last15=Jenkins |first15=J. S. |last16=Berdiñas |first16=Z. | last17=Diaz |first17=M. |last18=Kiraga |first18=M. | last19=Barnes |first19=J. R. |display-authors=1 | title=Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles | journal=Astronomy and Astrophysics | volume=616 | pages=A108 | year=2018 | bibcode=2018A&A...616A.108B | arxiv=1803.11123 | doi=10.1051/0004-6361/201629518 | s2cid=118915212 }}

|reference= |primary=ξ Sco A |name=ξ Sco B |period= |periastron=B |eccentricity= |axis= |inclination= |node= |periarg= |reference= |primary=ξ Sco AB |name=ξ Sco C |period=1514.43 |periastron=B 2226.10 |eccentricity=0.041 |axis=7.755 |inclination=131.5 |node=47.4 |periarg=59.3 |component1 = A | mass = 1.53 | temperature = 6,532 | component2 = B | mass2 = 1.53 | temperature2 = 6,532 | component1 = C | mass = 1.00 | temperature = 5,705 |component1=D |mass=0.89 |temperature=5,529 |luminosity=0.71 |radius=0.94 |gravity=4.49 |age_gyr=2.3 |component2=E |mass2=0.88 |temperature2=5,217 |luminosity2=0.44 |radius2=0.77 |gravity2=4.54 |age_gyr2=2.3 |component1=Components ABC |names1= |component2=ξ Sco A |names2= |component3=ξ Sco B |names3= |component4=ξ Sco C |names4= |component1=Components DE |names1= |component2=Component D |names2= |component3=Component E |names3= |Simbad=+ksi+Sco|sn=ξ Sco ABC |Simbad2=NAME++ksi+Sco+AB|sn2=ξ Sco AB |Simbad3=+ksi+Sco+A|sn3=ξ Sco A |Simbad4=+ksi+Sco+B|sn4=ξ Sco B |Simbad5=*+ksi+Sco+C|sn5=ξ Sco C |Simbad6=HD+144087|sn6=Component D |Simbad7=HD+144088|sn7=Component E |ARICNS=02736|an=ξ Sco A |ARICNS2=02737|an2=ξ Sco B |ARICNS3=02738|an3=ξ Sco C |ARICNS4=02739|an4=ξ Sco D |ARICNS5=02740|an5=ξ Sco E Xi Scorpii (ξ Sco) is part of a quintuple star system in the constellation Scorpius. It was assigned this designation by Bayer, although Ptolemy had catalogued the star in Libra. Flamsteed assigned it the designation 51 Librae, but this has fallen out of use since modern constellation boundaries assign the star to Scorpius.

Nomenclature

ξ Scorpii (Latinized to Xi Scorpii) is the star's Bayer designation. Xi Scorpii has no proper name, though it was erroneously known as Graffias before that name was applied to Beta Scorpii. Its Flamsteed designation is 51 Librae. When the modern constellation boundaries were drawn, Xi Scorpii was assigned to Scorpius, and the Flamsteed designation fell out of use.

The five stars of the Xi Scorpii system all have different designations, plus some designations that apply to more than one star. Xi Scorpii A, B, and C appear very close together in the sky and are typically grouped under a single multiple star designation, while components D and E are usually grouped under a separate multiple star designation. For example, Struve's catalogue of multiple stars includes the pair AB and C as Σ1998 and the pair D and E as Σ1999.

::data[format=table]

Component	Bayer	HR	HD	SAO	HIP	GJ
A	ξ Scorpii	5978	144070	159665	78727	9540
B	5977	144069
C	none	none	159666
D	none	none	144087	159668	78738	9541
E	none	none	144088	159670	78739
::

Properties

The Xi Scorpii system consists of five stars in two groups separated by about 4.7 arcminutes (or 0.08°) on the sky.

The brighter group contains Xi Scorpii A, B, and C. A and B are both yellow-white F-type stars. A is slightly brighter and warmer. They are separated by 0.744 arcseconds on average, and orbit around a common center once every 45.9 years. The dimmer, seventh-magnitude Xi Scorpii C orbits this pair at about ten times the distance, having a separation of around 7.6 arcseconds.

The second group contains components D and E, both K-type main-sequence stars, separated by about 11.9 arcseconds. They are known to be associated to each other and with the rest of the stars, because all stars share similar proper motions.

References

References

1. {{cite constellation. 51 Lib
2. (1988). "A new star catalogue of SAO type". Astronomy and Astrophysics Supplement Series.
3. "* ksi Sco".
4. "HD 144087".
5. "HD 144088".
6. Skiff, B. A.. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications". VizieR On-line Data Catalog.
7. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data.
8. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey.
9. (2002). "Statistics of spectroscopic sub-systems in visual multiple stars". Astronomy & Astrophysics.
10. {{cite Gaia DR3. 4343064577465522816
11. {{cite Gaia DR3. 4343064508746082304
12. "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory.
13. Tokovinin, Andrei. (2020-06-01). "Nearby Quintuple Systems κ Tucanae and ξ Scorpii". The Astronomical Journal.
14. (9 September 2019). "The Revised ''TESS'' Input Catalog and Candidate Target List". The Astronomical Journal.
15. (2020). "BAFFLES: Bayesian Ages for Field Lower-mass Stars". The Astrophysical Journal.
16. Allen, R. H.. (1899). "Star-names and Their Meanings". G. E. Stechert.
17. Wagman, M.. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy.
18. "** STF 1998".
19. "** STF 1999AB".
20. (1997). "MSC - a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series.

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