Astronomy:Xi Scorpii

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Coordinates: Sky map 16h 04m 22.1s, −11° 22′ 23″

Xi Scorpii
Observation data
{{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000]]      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000}}
Constellation Scorpius
ξ Sco ABC
Right ascension  16h 04m 22.191s[1]
Declination −11° 22′ 22.60″[1]
Apparent magnitude (V) 4.17[2]
(5.16 / 4.87 / 7.30)[3]
Component D
Right ascension  16h 04m 25.9260s[4]
Declination −11° 26′ 57.778″[4]
Apparent magnitude (V) 7.43[5]
Component E
Right ascension  16h 04m 26.7188s[6]
Declination −11° 26′ 59.553″[6]
Apparent magnitude (V) 7.81[7]
Characteristics
ξ Sco ABC
Spectral type F4(V) + F6(V) + G1V[8]
U−B color index +0.00[9]
B−V color index +0.45[9]
Components DE
Spectral type K1(V) + K1(V)[10]
U−B color index +0.315[9]
B−V color index +0.75[9]
Astrometry
ξ Sco ABC
Radial velocity (Rv)−36.33±0.83[11] km/s
Proper motion (μ) RA: −63.2[1] mas/yr
Dec.: −27.0[1] mas/yr
Component E
Radial velocity (Rv)−31.96±0.13[4] km/s
Proper motion (μ) RA: −61.607[4] mas/yr
Dec.: −22.227[4] mas/yr
Parallax (π)35.8898 ± 0.0200[4] mas
Distance90.88 ± 0.05 ly
(27.86 ± 0.02 pc)
Absolute magnitude (MV)4.47[12]
Component E
Radial velocity (Rv)−32.28±0.12[6] km/s
Proper motion (μ) RA: −56.334[6] mas/yr
Dec.: −20.357[6] mas/yr
Parallax (π)35.8718 ± 0.0237[6] mas
Distance90.92 ± 0.06 ly
(27.88 ± 0.02 pc)
Absolute magnitude (MV)5.18[12]
Orbit[3]
Primaryξ Sco A
Companionξ Sco B
Period (P)45.90±0.60 yr
Semi-major axis (a)0.654±0.006
Eccentricity (e)0.744±0.001
Inclination (i)34.5±1.0°
Longitude of the node (Ω)25.3±4.0°
Periastron epoch (T)B 1997.22±0.02
Argument of periastron (ω)
(secondary)
163.8±5.0°
Orbit[3]
Primaryξ Sco AB
Companionξ Sco C
Period (P)1514.43 yr
Semi-major axis (a)7.755″
Eccentricity (e)0.041
Inclination (i)131.5°
Longitude of the node (Ω)47.4°
Periastron epoch (T)B 2226.10
Argument of periastron (ω)
(secondary)
59.3°
Details
D
Mass0.89[4] M
Radius0.94[4] R
Luminosity0.71[4] L
Surface gravity (log g)4.49[13] cgs
Temperature5,529[13] K
Age2.3[14] Gyr
E
Mass0.88[6] M
Radius0.77[6] R
Luminosity0.44[6] L
Surface gravity (log g)4.54[13] cgs
Temperature5,217[13] K
Age2.3[14] Gyr
Other designations
Components ABC: {{{names1}}}
ξ Sco A: {{{names2}}}
ξ Sco B: {{{names3}}}
ξ Sco C: {{{names4}}}
Other designations
Components DE: {{{names1}}}
Component D: {{{names2}}}
Component E: {{{names3}}}
Database references
SIMBADξ Sco ABC
ξ Sco AB
ξ Sco A
ξ Sco B
ξ Sco C
Component D
Component E
ARICNSξ Sco A
ξ Sco B
ξ Sco C

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.[15]

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.[16] Its Flamsteed designation is 51 Librae.[15] 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 designation. For example, Struve's catalogue of multiple stars includes the pair AB and C as Σ1998[17] and the pair D and E as Σ1999.[18]

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.[19]

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.[8] They are separated by 0.744 arcseconds on average, and orbit around a common center once every 45.9 years.[3] The dimmer, seventh-magnitude Xi Scorpii C orbits this pair at about ten times the distance, having a separation of around 7.6 arcseconds.[3]

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.[19]

References

  1. 1.0 1.1 1.2 1.3 Roeser, S.; Bastian, U. (1988). "A new star catalogue of SAO type". Astronomy and Astrophysics Supplement Series 74: 449–451. Bibcode1988A&AS...74..449R. 
  2. "* ksi Sco". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+ksi+Sco. 
  3. 3.0 3.1 3.2 3.3 3.4 "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6. 
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  5. "HD 144087". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+144087. 
  6. 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  7. "HD 144088". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+144088. 
  8. 8.0 8.1 Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications". VizieR On-line Data Catalog 1. Bibcode2014yCat....1.2023S. 
  9. 9.0 9.1 9.2 9.3 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. 
  10. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey 5: 0. Bibcode1999MSS...C05....0H. 
  11. Tokovinin, A. A.; Smekhov, M. G. (2002). "Statistics of spectroscopic sub-systems in visual multiple stars". Astronomy & Astrophysics 382: 118–123. doi:10.1051/0004-6361:20011586. Bibcode2002A&A...382..118T. https://zenodo.org/record/896317. 
  12. 12.0 12.1 Boro Saikia, S. et al. (2018). "Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles". Astronomy and Astrophysics 616: A108. doi:10.1051/0004-6361/201629518. Bibcode2018A&A...616A.108B. 
  13. 13.0 13.1 13.2 13.3 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode2019AJ....158..138S. 
  14. 14.0 14.1 Stanford-Moore, S. Adam; Nielsen, Eric L.; De Rosa, Robert J.; MacIntosh, Bruce; Czekala, Ian (2020). "BAFFLES: Bayesian Ages for Field Lower-mass Stars". The Astrophysical Journal 898 (1): 27. doi:10.3847/1538-4357/ab9a35. Bibcode2020ApJ...898...27S. 
  15. 15.0 15.1 Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy 18 (3): 209. doi:10.1177/002182868701800305. Bibcode1987JHA....18..209W. 
  16. Allen, R. H. (1899). Star-names and Their Meanings. New York: G. E. Stechert. p. 371. https://archive.org/details/bub_gb_5xQuAAAAIAAJ. 
  17. "** STF 1998". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A%2A+STF+1998. 
  18. "** STF 1999AB". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A%2A+STF+1999AB. 
  19. 19.0 19.1 Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series 124: 75–84. doi:10.1051/aas:1997181. Bibcode1997A&AS..124...75T. 

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