Xi Ophiuchi information

Xi Ophiuchi
	Location of ξ Ophiuchi (circled)
Observation data; Epoch J2000 Equinox J2000
Constellation	Ophiuchus
Right ascension	17h 21m 00.37452s
Declination	−21° 06′ 46.5710″
Apparent magnitude (V)	4.39
Characteristics
Spectral type	F2V
U−B color index	-0.06
B−V color index	+0.41
Astrometry
Radial velocity (Rv)	−8.73±0.12 km/s
Proper motion (μ)	RA: +265.543 mas/yr ; Dec.: -202.584 mas/yr
Parallax (π)	57.0820 ± 0.1851 mas
Distance	57.1 ± 0.2 ly ; (17.52 ± 0.06 pc)
Absolute magnitude (MV)	3.19
Details
A
Mass	1.30 M☉
Radius	1.59±0.06 R☉
Luminosity	4.429±0.035 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 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
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]

^ ^a ^b ^c ^d ^e ^f Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference XHIP was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference Mallama2014 was invoked but never defined (see the help page).
^ ^a ^b ^c Cite error: The named reference Fuhrmann2017 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference David2015 was invoked but never defined (see the help page).
^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference WDS was invoked but never defined (see the help page).
^ Cite error: The named reference Haakonsen2009 was invoked but never defined (see the help page).
^ Cite error: The named reference allen1899 was invoked but never defined (see the help page).

[GaiaDR3-1] ^ ^a ^b ^c ^d ^e ^f Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).

[XHIP-2] Cite error: The named reference XHIP was invoked but never defined (see the help page).

[Gray2006-3] Cite error: The named reference Gray2006 was invoked but never defined (see the help page).

[Mallama2014-4] Cite error: The named reference Mallama2014 was invoked but never defined (see the help page).

[Fuhrmann2017-5] Cite error: The named reference Fuhrmann2017 was invoked but never defined (see the help page).

[GaiaDR2-6] Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).

[David2015-7] Cite error: The named reference David2015 was invoked but never defined (see the help page).

[SIMBAD-8] Cite error: The named reference SIMBAD was invoked but never defined (see the help page).

[Eggleton2008-9] Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).

[WDS-10] Cite error: The named reference WDS was invoked but never defined (see the help page).

[Haakonsen2009-11] Cite error: The named reference Haakonsen2009 was invoked but never defined (see the help page).

[allen1899-12] Cite error: The named reference allen1899 was invoked but never defined (see the help page).

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

Xi Ophiuchi information

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