| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16 30 54.82314 |
| Declination | +01° 59′ 02.1209″ |
| Apparent magnitude (V) | 3.82 4.18 + 5.22 + 11.0) |
| Characteristics | |
| Spectral type | A0V + A4V |
| U−B color index | +0.01 |
| B−V color index | +0.022±0.014 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −16.0±1.5 km/s |
| Proper motion (μ) | RA: –30.98 mas/yr Dec.: –73.42 mas/yr |
| Parallax (π) | 18.84 ± 0.55 mas |
| Distance | 173 ± 5 ly (53 ± 2 pc) |
| Absolute magnitude (MV) | 0.20 |
| Orbit | |
| 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 | |
| A | |
| Mass | 2.62±0.04 M☉ |
| Luminosity | 76.0+5.1 −4.8 L☉ |
| Temperature | 8,831+101 −102 K |
| Rotational velocity (v sin i) | 138 km/s |
| B | |
| Mass | 1.90 M☉ |
| C | |
| Mass | 0.72 M☉ |
| Other designations | |
| λ Oph, 10 Oph, NSV 7784, BD+02°3118, HD 148857, HIP 80883, HR 6149, SAO 121658, ADS 10087, WDS 16309+0159 | |
| Database references | |
| SIMBAD | data |
λ Ophiuchi, Latinized as Lambda Ophiuchi, is a triple star system in the equatorial constellation of Ophiuchus. It has the traditional name Marfik /ˈmɑːrfɪk/, which now applies exclusively to the primary component. The system is visible to the naked eye as a faint point of light with an apparent visual magnitude of 3.82. It is located approximately 173 light-years from the Sun, based on its parallax, but is drifting closer with a radial velocity of –16 km/s.
System
The inner pair form a binary star system with an orbital period of 192 years and an eccentricity of 0.611. Both components are A-type main-sequence stars, indicating that they are generating energy through core hydrogen fusion. The brighter member of this pair, designated component A, is the primary for the system with a visual magnitude of 4.18 and a stellar classification of A0V. The secondary, component B, is magnitude 5.22 and class A4V.
Component C is magnitude 11.0 and lies at an angular separation of 119″ from the inner pair. It has a common proper motion and is at approximately the same distance as the other two stars, although any orbit would last for hundreds of thousands of years. It has a mass 72% of the Sun's, a radius 58% of the Sun's, a temperature of about 4,157 K, and 7% of the Sun's luminosity. It has an estimated spectral type of K6.
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).
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) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. 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.
References
- ^ Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ 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.
- ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
- ^ Edwards, T. W. (1976). "MK classification for visual binary components". The Astronomical Journal. 81: 245. Bibcode:1976AJ.....81..245E. doi:10.1086/111879.
- Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
- Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
- ^ 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. S2CID 121998591.
- ^ Zorec, J.; et al. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789.
- ^ A. Tokovinin. "HR 6149". Multiple Star Catalogue.
- ^ "lam Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-20.
- Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
- ^ "Naming Stars". IAU.org. Retrieved 16 December 2017.
- 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. S2CID 14376211.
- ^ 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.
- Hessman, F. V.; et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 .
- IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
- "WG Triennial Report (2015–2018) – Star Names" (PDF). p. 5. Retrieved 2018-07-14.
