Lambda Ophiuchi

From Wikipedia, the free encyclopedia
  (Redirected from Marfik)
Jump to navigation Jump to search
Lambda Ophiuchi
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 16h 30m 54.8229s[1]
Declination +01° 59′ 02.123″[1]
Apparent magnitude (V) 3.90[2]
Characteristics
Spectral type A0V+[2]
U−B color index +0.01[3]
B−V color index +0.01[3]
Variable type Suspected
Astrometry
Radial velocity (Rv)–13.5[4] km/s
Proper motion (μ) RA: –31.37 mas/yr
Dec.: –73.00 mas/yr
Parallax (π)19.63 ± 1.34[1] mas
Distance170 ± 10 ly
(51 ± 3 pc)
Orbit[5]
Period (P)192 yr
Semi-major axis (a)0.91″
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°
Details
Rotational velocity (v sin i)138[6] km/s
Other designations
λ Oph, 10 Oph, HR 6149, BD+02° 3118, HD 148857, SAO 121658, HIP 80883, WDS 16309+0159.[2]
Database references
SIMBADdata

Lambda Ophiuchi (λ Ophiuchi, abbreviated Lambda Oph, λ Oph) is a triple star system in the constellation of Ophiuchus. It is approximately 170 light-years from the Sun, based on its parallax.[1]

The system consists of a binary pair[7], designated Lambda Ophiuchi AB, together with a third companion, C. AB's two components are themselves designated Lambda Ophiuchi A (also named Marfik[8]) and B.

Nomenclature[edit]

λ Ophiuchi (Latinised to Lambda 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).[9]

It bore the traditional name Marfik (or Marsik), meaning "the elbow" in Arabic. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[10] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[11] 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.[8]

Properties[edit]

Lambda Ophiuchi has apparent magnitude +3.82. Its to spectral type is A1V+A. The two components orbit each other with an period of 129 years.[5]

References[edit]

  1. ^ a b c d Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
  2. ^ a b c "lam Oph -- Variable Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 8 June 2010.
  3. ^ a b Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99). Bibcode:1966CoLPL...4...99J.
  4. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick. Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.
  5. ^ a b Heintz, W. D.; Strom, C. (1993). "The visual binary Lambda Ophiuchi". Astronomical Society of the Pacific. 105 (685): 293. Bibcode:1993PASP..105..293H. doi:10.1086/133145.
  6. ^ Royer, F.; Zorec, J.; Gómez, A. E. (February 2007). "Rotational velocities of A-type stars. III. Velocity distributions". Astronomy and Astrophysics. 463 (2): 671–682. arXiv:astro-ph/0610785. Bibcode:2007A&A...463..671R. doi:10.1051/0004-6361:20065224.
  7. ^ Lastennet, E.; Fernandes, J.; Lejeune, Th. (June 2002). "A revised HRD for individual components of binary systems from BaSeL BVRI synthetic photometry. Influence of interstellar extinction and stellar rotation". Astronomy and Astrophysics. 388: 309–319. arXiv:astro-ph/0203341. Bibcode:2002A&A...388..309L. doi:10.1051/0004-6361:20020439.
  8. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  9. ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  10. ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  11. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.

External links[edit]