Nu Ophiuchi

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Template:Short description

ν Ophiuchi
Template:Location mark
Location of ν Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) +3.332[2]
Characteristics
Spectral type K0 IIIa CN –1[3]
U−B Template:Engvar +0.873[2]
B−V Template:Engvar +0.999[2]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[4] km/s
Proper motion (μ) RA: Script error: No such module "val". mas/yr[1]
Dec.: Script error: No such module "val". mas/yr[1]
Parallax (π)21.64±0.26 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)–0.19[5]
Details[4]
MassScript error: No such module "val". Template:Solar mass
RadiusScript error: No such module "val".[6] Template:Solar radius
LuminosityScript error: No such module "val".[6] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val". cgs
TemperatureScript error: No such module "val".[6] K
Metallicity [Fe/H]Script error: No such module "val". dex
Rotational velocity (v sin i)2.1[7] km/s
AgeScript error: No such module "val". Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Sinistra, 64 Ophiuchi, BD−09 4632, FK5 673, HD 163917, HIP 88048, HR 6698, SAO 142004, 2MASS J17590160-0946249[8]
Database references
SIMBADdata

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Nu Ophiuchi (ν Oph, ν Ophiuchi) is a star in the equatorial constellation of Ophiuchus. The apparent visual magnitude is +3.3,[2] making it one of the brighter members of this constellation. Based upon parallax measurements made by the Hipparcos satellite, this star is located at a distance of about Script error: No such module "convert"..[1]

Properties

File:Nu Ophiuchi and Companion.png
Nu Ophiuchi and its brown dwarf companion Nu Ophiuchi b

Nu Ophiuchi has about three times the mass of the Sun and is roughly 450 million years old. [4] The spectrum of the star matches a stellar classification of K0 IIIa,[3] indicating it is a giant star that has exhausted the supply of hydrogen at its core and evolved away from the main sequence of stars. Unusually, it displays an anomalously low abundance of cyanogen for a star of its type.[3] The star's outer envelope has expanded to around 14 times the Sun's radius and now radiates with a luminosity 108 times that of the Sun. This energy is emitted from its outer envelope at an effective temperature of 5,000 K,[6] giving it the cool, orange hue of a K-type star.[9]

Companions

This is not a binary star system in the sense of having a gravitationally-bound stellar companion.[10] However, in November 2003, a brown dwarf companion called Nu Ophiuchi b was discovered. This sub-stellar companion has at least 21.9 times the mass of Jupiter and takes 536 days (1.47 years) to complete an orbit.[11] A second brown dwarf companion was discovered in 2010, orbiting further from the star with a period of 3,169 days (8.68 years). These were confirmed in 2012.[12] The two brown dwarfs are locked in a 1:6 orbital resonance.[13]

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This star is following an orbit through the galaxy that carries it between Script error: No such module "convert". from the Galactic Center. As a probable member of the Milky Way's thin disk population, it has a low orbital inclination that carries it no more than about Script error: No such module "convert". above the galactic plane.[14]

Naming

This star is sometimes called by the name Sinistra, meaning left side in Latin,[15] although authors like Jim Kaler recommend not using this name, and instead stick to the Bayer designation only (Nu Ophiuchi).[16]

In China, the star is part of Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Left Wall of Heavenly Market Enclosure. The stars in this group include ν Ophiuchi, δ Herculis, λ Herculis, μ Herculis, ο Herculis, 112 Herculis, ζ Aquilae, θ1 Serpentis, η Serpentis, ξ Serpentis and η Ophiuchi.[17] Consequently, ν Ophiuchi itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx), and together with ζ Capricorni represents the state Yan (燕)[18][19] in the Twelve States constellation.[20]

See also

References

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  1. a b c d e Script error: No such module "citation/CS1". Nu Ophiuchi's database entry at VizieR.
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  4. a b c Script error: No such module "citation/CS1". Nu Ophiuchi's database entry at VizieR.
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  6. a b c d Script error: No such module "citation/CS1".
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Template:Stars of Ophiuchus