Xi Ophiuchi

{{Short description|Visual binary star system in the constellation Ophiuchus}}

{{Starbox image

| image =

{{Location mark

|image=Ophiuchus constellation map.svg|alt=|float=center|width=280

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=Xi Ophiuchi

|x=485|y=816

}}

| caption = Location of ξ Ophiuchi (circled)

}}

{{Starbox observe

| epoch = J2000

| constell = Ophiuchus

| ra = {{RA|17|21|00.37452}}

| dec = {{DEC|-21|06|46.5710}}

| appmag_v = 4.39

}}

{{Starbox character

| type =

| class = F2V

| b-v = +0.41

| u-b = −0.06

| variable =

}}

{{Starbox astrometry

| radial_v = {{val|-8.73|0.12}}

| prop_mo_ra = +265.543

| prop_mo_dec = −202.584

| pm_footnote =

| parallax = 57.0820

| p_error = 0.1851

| parallax_footnote =

| absmag_v = 3.19

}}

{{Starbox detail

| source =

| component1 = A

| mass = 1.30

| radius = {{Val|1.59|0.06}}

| temperature = {{Val|6611|80|fmt=commas}}

| luminosity = {{Val|4.429|0.035}}

| rotational_velocity = {{Val|20.2|0.7}}

| gravity = {{Val|4.15|0.10}}

| metal_fe = {{Val|−0.27|0.07}}

| age_myr = 916

}}

{{Starbox catalog

| names = {{odlist | B=ξ Oph | F=40 Ophiuchi | BD=-20°4731 | FK5=917 | HD=156897 | HIP=84893 | HR=6445 | SAO=185296 | CCDM=J17210-2107AB | GC=23423 | LTT=6908 | WDS=J17210-2107AB }}

}}

{{Starbox reference

| Simbad = ksi+Oph

}}

ξ Oph, Latinized as Xi Ophiuchi, is a visual binary star system in the equatorial constellation of Ophiuchus. It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.39. The system is located approximately {{convert|57.1|ly|pc|lk=on|abbr=off}} away from the Sun based on parallax, but is drifting closer with a radial velocity of -9 km/s.

The magnitude 4.40 primary, designated component A, is an ordinary F-type main-sequence star with a stellar classification of F2V. It is 916 million years old and is rotating with a projected rotational velocity of 20 km/s. The star has 1.3 times the mass of the Sun and 1.6 times the Sun's radius. It is radiating 4.4 times the luminosity of the Sun from its photosphere at an effective temperature of 6,611 K.

The system is a source of X-ray emission. The orbiting companion, component B, is a magnitude 8.9 star at an angular separation of {{Val|4.1|ul=arcsecond}} along a position angle of 26° from the primary, as of 2016. A magnitude 10.8 visual companion, component C, lies at a separation of {{Val|10.8|u=arcsecond}}, as of 2004.

According to Richard H. Allen's Star Names: Their Lore and Meaning (1899), ξ Oph together with θ Oph formed the Sogdian Wajrik "the Magician", the Khorasmian Markhashik "the Serpent-bitten" and with η Oph the Coptic Tshiō, "the Snake", and Aggia, "the Magician". The name Aggia for this star appears in a 1971 NASA list of star names and in a 2023 list of target stars for the Habitable Worlds Observatory. {{as of|2025|05}}, it does not appear in the IAU Catalog of Star Names.

References

{{reflist|refs=

{{cite simbad

| title=ksi Oph | access-date=2019-10-08 }}

{{cite journal

| last1=Fuhrmann | first1=K. | last2=Chini | first2=R.

| last3=Kaderhandt | first3=L. | last4=Chen | first4=Z.

| title=Multiplicity among Solar-type Stars

| journal=The Astrophysical Journal

| volume=836 | issue=1 | pages=139 | year=2017

| bibcode=2017ApJ...836..139F | doi=10.3847/1538-4357/836/1/139 | doi-access=free }}

{{cite journal

| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.

| title=A catalogue of multiplicity among bright stellar systems

| journal=Monthly Notices of the Royal Astronomical Society

| volume=389 | issue=2 | pages=869–879 | date=September 2008

| doi=10.1111/j.1365-2966.2008.13596.x

| doi-access=free | bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}

{{cite journal

| last1=Haakonsen | first1=Christian Bernt | last2=Rutledge | first2=Robert E.

| title=XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources

| journal=The Astrophysical Journal Supplement

| volume=184 | issue=1 | pages=138–151 | date=September 2009

| doi=10.1088/0067-0049/184/1/138 | bibcode=2009ApJS..184..138H

| arxiv=0910.3229 | s2cid=119267456 }}

{{cite journal

| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

| title=XHIP: An extended hipparcos compilation

| journal=Astronomy Letters

| volume=38 | issue=5 | pages=331 | year=2012

| bibcode=2012AstL...38..331A | arxiv=1108.4971

| doi=10.1134/S1063773712050015

| s2cid=119257644 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=V/137D/XHIP&HIP=84893 Vizier catalog entry]

{{cite journal

| last1=Gray | first1=R. O. | last2=Corbally | first2=C. J.

| last3=Garrison | first3=R. F. | last4=McFadden | first4=M. T.

| last5=Bubar | first5=E. J. | last6=McGahee | first6=C. E.

| last7=O'Donoghue | first7=A. A. | last8=Knox | first8=E. R.

| title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample

| journal=The Astronomical Journal

| volume=132 | pages=161–170 | year=2006

| issue=1 | doi=10.1086/504637 | arxiv=astro-ph/0603770

| bibcode=2006AJ....132..161G | s2cid=119476992 }}

{{cite journal

| last=Mallama | first=A.

| title=Sloan Magnitudes for the Brightest Stars

| journal=The Journal of the American Association of Variable Star Observers

| volume=42 | pages=443 | year=2014

| issue=2

| bibcode=2014JAVSO..42..443M

}}[http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=J/other/JAVSO/42.443/ugriz&HD=156897 Vizier catalog entry]

{{cite journal

| last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A.

| title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets

| journal=The Astrophysical Journal

| volume=804 | issue=2 | pages=146 | year=2015

| bibcode=2015ApJ...804..146D | arxiv=1501.03154

| doi=10.1088/0004-637X/804/2/146

| s2cid=33401607 }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=J/ApJ/804/146/table5&HIP=84893 Vizier catalog entry]

{{cite journal

| display-authors=1 | last1=Mason | first1=Brian D.

| last2=Wycoff | first2=Gary L. | last3=Hartkopf | first3=William I.

| last4=Douglass | first4=Geoffrey G. | last5=Worley | first5=Charles E.

| title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog

| journal=The Astronomical Journal

| volume=122 | issue=6 | pages=3466 | year=200

| bibcode=2001AJ....122.3466M | doi=10.1086/323920

| doi-access=free }} [http://vizier.u-strasbg.fr/viz-bin/VizieR-4?-source=B/wds/wds&WDS=17210-2107 Vizier catalog entry]

{{citation | first1=R.H. | last1=Allen | title=Star Names: Their Lore and Meaning | date=1899 | url=https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Ophiuchus*.html | page=297 }}

{{citation

| first=Jack W. | last=Rhoads

| title=Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars

| publisher=Jet Propulsion Laboratory, California Institute of Technology

| url=https://ntrs.nasa.gov/api/citations/19720005197/downloads/19720005197.pdf

| date=November 15, 1971 | postscript=. }}

{{cite report |last1=Mamajek |first1=Eric |last2=Stapelfeldt |first2=Karl |date=January 2023 |title=NASA Exoplanet Exploration Program (ExEP) Mission Star List for the Habitable Worlds Observatory (2023) |url=https://exoplanetarchive.ipac.caltech.edu/docs/2645_NASA_ExEP_Target_List_HWO_Documentation_2023.pdf |arxiv=2402.12414 |id=JPL CL#23-0611}}

{{cite web |title=IAU Catalog of Star Names |url=https://exopla.net/star-names/modern-iau-star-names/ |access-date=22 February 2025}}

}}

Category:F-type main-sequence stars

Category:Binary stars