Xi Ophiuchi

Visual binary star system in the constellation Ophiuchus

Xi Ophiuchi
Observation data Epoch J2000 Equinox J2000
Location of ξ Ophiuchi (circled)
Constellation	Ophiuchus
Right ascension	17^h 21^m 00.37452^s^[1]
Declination	−21° 06′ 46.5710″^[1]
Apparent magnitude (V)	4.39^[2]
Characteristics
Spectral type	F2V^[3]
U−B color index	-0.06^[4]
B−V color index	+0.41^[4]
Astrometry

Radial velocity (R_v)	−8.73±0.12^[1] km/s
Proper motion (μ)	RA: +265.543 mas/yr^[1] Dec.: -202.584 mas/yr^[1]
Parallax (π)	57.0820 ± 0.1851 mas^[1]
Distance	57.1 ± 0.2 ly (17.52 ± 0.06 pc)
Absolute magnitude (M_V)	3.19^[2]

Details^[5]
A
Mass	1.30 `M`_☉
Radius	1.59±0.06 `R`_☉
Luminosity	4.429±0.035^[6] `L`_☉
Surface gravity (log g)	4.15±0.10 cgs
Temperature	6,611±80 K
Metallicity [Fe/H]	−0.27±0.07 dex
Rotational velocity (v sin i)	20.2±0.7 km/s
Age	916^[7] Myr

Other designations
ξ Oph, 40 Ophiuchi, BD−20°4731, FK5 917, GC 23423, HD 156897, HIP 84893, HR 6445, SAO 185296, CCDM J17210-2107AB, WDS J17210-2107AB, LTT 6908^[8]
Database references
SIMBAD	data

ξ Oph, Latinized as Xi Ophiuchi, is a visual binary star^[9] system in the equatorial constellation of Ophiuchus.^[2] It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.39.^[2] The system is located approximately 57.1 light-years (17.5 parsecs) away from the Sun based on parallax, but is drifting closer with a radial velocity of -9 km/s.^[1]

The magnitude 4.40^[10] primary, designated component A, is an ordinary F-type main-sequence star with a stellar classification of F2V.^[3] It is 916^[7] 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.^[5] It is radiating 4.4^[6] times the luminosity of the Sun from its photosphere at an effective temperature of 6,611 K.^[5]

The system is a source of X-ray emission.^[11] The orbiting companion, component B, is a magnitude 8.9 star at an angular separation of 35″ along a position angle of 27° from the primary, as of 2015. A magnitude 10.8 visual companion, component C, lies at a separation of 10.8″, as of 2004.^[10]

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".^[12]

References

^ ^a ^b ^c ^d ^e ^f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
^ ^a ^b ^c ^d Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. Vizier catalog entry
^ ^a ^b Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
^ ^a ^b Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
^ ^a ^b ^c Fuhrmann, K.; Chini, R.; Kaderhandt, L.; Chen, Z. (2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal. 836 (1): 139. Bibcode:2017ApJ...836..139F. doi:10.3847/1538-4357/836/1/139.
^ ^a ^b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
^ ^a ^b David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607. Vizier catalog entry
^ "ksi Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-08.
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
^ ^a ^b Mason, Brian D.; et al. (200). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Vizier catalog entry
^ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009). "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources". The Astrophysical Journal Supplement. 184 (1): 138–151. arXiv:0910.3229. Bibcode:2009ApJS..184..138H. doi:10.1088/0067-0049/184/1/138. S2CID 119267456.
^ Allen, R.H. (1899), Star Names: Their Lore and Meaning, p. 297

Constellation of Ophiuchus

Stars

Bayer	α (Rasalhague) β (Cebalrai) γ δ (Yed Prior) ε (Yed Posterior) ζ (Han) η (Sabik) θ ι κ λ (Marfik) μ ν ξ ο ρ σ τ υ φ χ ψ ω
Flamsteed	12 14 15 16 18 19 20 21 23 24 26 28 29 30 31 36 (A, Guniibuu) 37 38 41 43 44 (b) 45 (d, θ Tel) 50 51 (c) 52 53 (f) 54 58 61 66 67 68 70 (p) 71 72 73 74 24 Sco
Variable	U V X Y RS RV RZ ST SW TT TW UU WZ XX BF IX KK V380 V426 V438 V442 V445 V451 V453 V502 V508 V566 V567 V716 V839 V841 V849 V986 V1010 V1054 V2051 V2052 V2076 V2105 V2112 V2113 V2114 V2118 V2126 V2129 V2213 V2214 V2247 V2291 V2292 V2293 V2295 V2301 V2306 V2307 V2324 V2368 V2388 V2393 V2400 V2487 V2500 (Barnard's Star) V2502 V2540 V2542
HR	5989 5990 6041 6067 6096 6124 6136 6137 6140 6144 6179 6189 6190 6193 6201 6202 6235 6248 6269 6284 6294 6296 6302 6308 6329 6340 6350 6353 6354 6358 6359 6361 6365 6367 6372 6375 6387 6390 6404 6413 6428 6433 6435 6439 6441 6465 6472 6473 6474 6476 6489 6490 6494 6497 6504 6507 6512 6516 6520 6521 6524 6532 6534 6575 6577 6578 6590 6593 6601 6633 6639 6650 6659 6667 6670 6686 6689 6690 6696 6706 6719 6784 6797 6800 6851 6857 6883 6902 6925 6976 6985 6987 7010
HD	148390 148427 (Timir) 148531 149143 (Rosalíadecastro) 149382 150052 150381 150433 150493 152581 (Mahsati) 154088 156992 157172 160042 160346 164509 167162 170469 171028
Other	AS 239 BD-9 4395 CFHTWIR-Oph 98 CoRoT-6 CoRoT-25 CoRoT-26 DoAr 21 Elias 2-27 Gaia BH1 Gliese 673 GJ 1207 GJ 1214 GRS 1739-278 GX 1+4 GX 9+9 H 1705-250 Hen 3-1341 Great Annihilator IRAS 16293−2422 K2-32 LS IV-1 2 2MASS J16452211-1319516 MXB 1659-29 Oph-IRS 48 PG 1627-017 PSR B1929+10 TOI-677 Van Biesbroeck 8 VVV BD001 WISE 1800+0134 WISEP J180026.60+013453.1 Wolf 635 XTE J1739-285

Exoplanets	CFHTWIR-Oph 98 b CoRoT-6b 25b 26b GJ 1214 b (Enaiposha) ν Ophiuchi b c

Star
clusters

NGC	6284 6287 6293 6304 6316 6325 6342 6355 6356 6366 6401 6426 6633
Other	IC 4665 Melotte 186 Messier 9 Messier 10 Messier 12 Messier 14 Messier 19 Messier 62 Messier 107 Palomar 6

Nebulae

NGC	6309 6572
Other	Dark Horse Double Helix Nebula Ophiuchus Superbubble Pipe Nebula Rho Ophiuchi cloud complex Serpens–Aquila Rift Snake Nebula