Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 16h 49m 50.01604s [1] |
Declination | −10° 46′ 58.7775″ [1] |
Apparent magnitude (V) | 4.64 [2] |
Characteristics | |
Spectral type | F6IV [3] |
U−B color index | +0.07 [4] |
B−V color index | +0.47 [4] |
Astrometry | |
Radial velocity (Rv) | -1.60 [5] km/s |
Proper motion (μ) | RA: +72.33 [1] mas/yr Dec.: -78.80 [1] mas/yr |
Parallax (π) | 31.27 ± 2.16 mas [1] |
Distance | 104 ± 7 ly (32 ± 2 pc) |
Absolute magnitude (MV) | 2.13 [2] |
Orbit [6] | |
Period (P) | 35.5 ± 1.5 yr |
Semi-major axis (a) | 0.460 ± 0.030″ |
Eccentricity (e) | 0.8 ± 0.2 |
Inclination (i) | 74 ± 11° |
Longitude of the node (Ω) | 118 ± 9° |
Periastron epoch (T) | 1981.2 ± 1.7 |
Argument of periastron (ω) (secondary) | 34 ± 26° |
Details | |
20 Oph A | |
Mass | 1.70 [7] M☉ |
Radius | 3.0 [7] R☉ |
Luminosity | 12.06 [2] L☉ |
Surface gravity (log g) | 3.89 [8] cgs |
Temperature | 6,417 [8] K |
Metallicity [Fe/H] | +0.13 [8] dex |
Rotational velocity (v sin i) | 11.3 [9] km/s |
20 Oph B | |
Mass | 0.8 ± 0.2 [6] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
20 Ophiuchi is a class F6IV [3] (yellow-white subgiant) star in the constellation Ophiuchus. Its apparent magnitude is 4.64 [2] and it is approximately 104 light years away based on parallax. [1] It lies near the star Zeta Ophiuchi.
20 Ophiuchi is an astrometric binary. The primary star is a late F-type subgiant star. It has a mass 1.72 times that of the Sun. [6] The companion star regularly perturbs the primary star, causing it to wobble around the barycenter. From this, an orbital period of 35.5 years has been calculated. The secondary star is 0.8 times the mass of the Sun, and it may be a white dwarf or red dwarf. [6]
Zeta Scuti, Latinized from ζ Scuti, is the Bayer designation for a star in the southern constellation of Scutum. It is a faint star but visible to the naked eye with an apparent magnitude of 4.66. The distance to this star, as determined via parallax measurement, is around 210 light years. It is moving closer to the Sun with a radial velocity of −5 km/s.
13 Vulpeculae is a blue giant with a stellar classification of class B9.5III in the northern constellation Vulpecula. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.57 and it is approximately 339 light years away from the Sun based on parallax. The star is radiating 180 times the luminosity of the Sun from its photosphere at an effective temperature of 8,801 K.
9 Vulpeculae is a star in the northern constellation of Vulpecula, located about 560 light years away based on parallax. It is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 5.01. The star is moving further from the Earth with a heliocentric radial velocity of +5 km/s.
μ Ophiuchi, Latinized as Mu Ophiuchi, is a solitary, blue-white hued star in the equatorial constellation of Ophiuchus. It is visible to the naked as a faint point of light with an apparent visual magnitude of 4.62. This object is located approximately 760 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −18.5 km/s.
68 Ophiuchi is a binary star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 4.42. The system is located around 89.69 parsecs (292.5 ly) distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +6 km/s.
ε Monocerotis, Latinised as Epsilon Monocerotis, is the Bayer designation of a binary star system in the equatorial constellation Monoceros. Its location is a guide for sky navigation toward the Rosette Nebula.
Beta Octantis, Latinized from β Octantis, is a probable astrometric binary star system in the southern circumpolar constellation of Octans. It is faintly visible to the naked eye with an apparent visual magnitude of 4.13. Based upon an annual parallax shift of 21.85 mas as seen from Earth, it is located about 149 light years from the Sun. It is moving away from the Sun with a radial velocity of +19 km/s.
44 Ophiuchi is a single star in the constellation Ophiuchus. It has the Bayer designation b Ophiuchi, while 44 Ophiuchi is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.16. The distance to this object is approximately 83.2 light years based on parallax. It is drifting closer to the Earth with a heliocentric radial velocity of -37.2 km/s, and is predicted to come within 30 light-years around 585,000 years from now.
45 Ophiuchi is a single star in the equatorial constellation of Ophiuchus, along the southern border with Scorpius. It has the Bayer designation d Ophiuchi, while 45 Ophiuchi is the Flamsteed designation. In the past it had the designation Theta Telescopii. This object is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.28. It is located approximately 111.6 light years away from the Sun based on parallax. The star is drifting further from the Earth with a heliocentric radial velocity of +38 km/s.
ι Ophiuchi, Latinized as Iota Ophiuchi, is a single star in the equatorial constellation of Ophiuchus, positioned near the constellation border with Hercules. It makes a naked-eye double with nearby Kappa Ophiuchi, appearing as a faint, blue-white hued star with an apparent visual magnitude of 4.39. The star is approximately 245 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −19 km/s.
κ Delphini is a binary star system in the constellation Delphinus. It is faintly visible to the naked eye, with an apparent magnitude of 5.05. It is located about 98.8 light-years away, based on its parallax.
58 Ophiuchi is a single star in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.86. This object is approximately 57.6 light years away based on parallax, and is drifting further from the Earth with a heliocentric radial velocity of +10 km/s.
Rho Pegasi, Latinized from ρ Pegasi, is a star in the northern constellation of Pegasus, near the southern constellation boundary with Pisces. This is a probable astrometric binary system, as determined by changes to the proper motion of the visible component. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.90. The system is located at a distance of approximately 274 light years from the Sun based on parallax, but it is drifting closer with a radial velocity of −10.6 km/s.
Eta Phoenicis is a class A0IV star in the constellation Phoenix. Its apparent magnitude is 4.36 and it is approximately 246 light years away based on parallax.
Gamma Pictoris, Latinised from γ Pictoris, is a single, orange-hued star in the southern constellation of Pictor. It is a faintly visible to the naked eye with an apparent visual magnitude of 4.50. Based upon an annual parallax shift of 18.45 mas as seen from Earth, this star is located about 177 light-years from the Sun. It is moving away from the Sun with a radial velocity of +15.7 km/s.
16 Puppis is a suspected astrometric binary star system in the southern constellation of Puppis, and is located in the northernmost part of its constellation, almost due north of the bright star Rho Puppis, and east of Canis Major. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.40. The star is located is approximately 465 light years away from the Sun based on parallax. It was the brightest star in Officina Typographica, an obsolete constellation.
HD 65810 is a class A2V star in the constellation Puppis. Its apparent magnitude is 4.61 and it is approximately 241 light years away based on parallax.
HD 63744 is a class K0III star in the constellation Puppis. Its apparent magnitude is 4.71 and it is approximately 232 light years away based on parallax.
31 Persei is a single star in the northern constellation of Perseus. It is visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.05. This star is located around 172 parsecs (560 ly) away from the Sun, and it is drifting closer with a radial velocity of −1.6 km/s. It is likely a member of the Alpha Persei Cluster.
Gamma1 Octantis, Latinized from γ1 Octantis, is a single, yellow-hued star in the constellation which includes the southern celestial pole, Octans. Its apparent visual magnitude is 5.10, meaning that in good conditions it is bright enough to be faintly visible to the naked eye.