Lambda Ophiuchi
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.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 30m 54.82314s |
| 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 | |
| Database references | |
| SIMBAD | data |
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