Lambda Ophiuchi

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Template:Short description

Lambda Ophiuchi
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.82[2]
(4.18 (A) + 5.22 (B) + 11.0 (C))[3]
Characteristics
Spectral type A0V + A4V[4]
U−B Template:Engvar +0.01[5]
B−V Template:Engvar Template:Val[2]
Variable type Suspected[6]
Astrometry
Radial velocity (Rv)Template:Val[2] km/s
Proper motion (μ) RA: −30.98[1] mas/yr
Dec.: −73.42[1] mas/yr
Parallax (π)18.84±0.55 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)0.20[2]
Orbit[7]
PrimaryA
CompanionB
Period (P)192 yr
Semi-major axis (a)Template:Val[7]
(47.8 AU)[8]
Eccentricity (e)0.611
Inclination (i)23.0°
Longitude of the node (Ω)53.3°
Periastron epoch (T)B 1939.7
Argument of periastron (ω)
(secondary)		157.5°
Orbit[8]
PrimaryAa
CompanionAb
Period (P)1 month
Semi-major axis (a)Template:Val
Details[8]
Aa
Mass2.39 Template:Solar mass
Radius2.45 Template:Solar radius
LuminosityTemplate:Val[9] Template:Solar luminosity
Temperature9,550 K
Rotational velocity (v sin i)138[9] km/s
Ab
Mass1.62 Template:Solar mass
Radius1.56 Template:Solar radius
Temperature7,710 K
Metallicity [Fe/H]{{{metal_fe2}}} dex
B
Mass1.82 Template:Solar mass
Radius1.73 Template:Solar radius
Temperature8,330 K
Metallicity [Fe/H]{{{metal_fe2}}} dex
C
Mass0.62 Template:Solar mass
Radius0.58[10] Template:Solar radius
Luminosity0.09[10] Template:Solar luminosity
TemperatureTemplate:Val[10] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[11]
Database references
SIMBADdata

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λ Ophiuchi, Latinized as Lambda Ophiuchi, is a quadruple star system[8] in the equatorial constellation of Ophiuchus. It has the traditional name Marfik Template:IPAc-en,[12] which now applies exclusively to the primary component.[13] The system is visible to the naked eye as a faint point of light with an apparent visual magnitude of 3.82.[2] It is located approximately 173 light-years from the Sun, based on its parallax,[1] but is drifting closer with a radial velocity of –16 km/s.[2]

System

The system can be divided in three pairs and is in a hierarchical architecture, with orbits inside others. The inner pair is made up of the components Aa and Ab, which take about one month to complete an orbit around each other and are separated by 0.32 astronomical units.[8] It has a combined visual magnitude of 4.18.[3] The primary is an A-type main-sequence star, with a class of A0V, indicating that it is generating energy through core hydrogen fusion.[4] It has about 2.45 times the Sun's radius and an effective temperature of 9,550 K,[8] giving it the blue-white hue typical of early A-type stars.[14] The secondary is slightly cooler and smaller, with 1.56 times the Sun's radius and an effective temperature of 7,710 K.[8] This temperature is close to the dividing line between F and A-type stars and give it a white hue.[14]

The A-B system has an orbital period of 192 years, a physical separation of 48 AU and an eccentricity of 0.611.[7][8] The secondary, component B, of magnitude 5.22,[3] is also an A-type main-sequence star, with a spectral class A4V.[4] It is 1.73 times as large as the Sun and has an effective temperature of 8,330 K,[8] giving it the white hue of A-type stars.[14]

Component C is magnitude 11.0 and lies at an angular separation of Template:Val from the A-B pair,[3] translating to 6,370 astronomical units at its distance.[8] It has a common proper motion and is at approximately the same distance as the other two stars,[10] although any orbit would last for hundreds of thousands of years.[15] It has a mass 62% of the Sun's,[8] a radius 58% of the Sun's, a temperature of about Template:Val, and 9% of the Sun's luminosity.[10] It has an estimated spectral type of K6.[15]

Nomenclature

λ Ophiuchi is the system's Bayer designation. The designations of the three components as Lambda Ophiuchi A, B and C derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[16]

It bore the traditional name Marfik (or Marsik), from the Arabic مرفق marfiq "elbow". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[17] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[18] It approved the name Marfik for the component Lambda Ophiuchi A on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[13]

References

Template:Reflist

External links

Template:Stars of Ophiuchus

  1. ↑ a b c d e f Cite error: Invalid <ref> tag; no text was provided for refs named vanLeeuwen2007
  2. ↑ a b c d e f Cite error: Invalid <ref> tag; no text was provided for refs named Anderson2012
  3. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named Eggleton2008
  4. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named Edwards1976
  5. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named clpl4
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Samus2017
  7. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named orb
  8. ↑ a b c d e f g h i j k Cite error: Invalid <ref> tag; no text was provided for refs named Waisberg2023
  9. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named zorec2012
  10. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named dr2c
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Kunitzsch
  13. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named IAU-LSN
  14. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named csiro
  15. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named msc
  16. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named planetnaming
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named WGSN
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named TriRpt18
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