Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 17h 20m 34.31093s [1] |
Declination | −19° 20′ 01.4944″ [1] |
Apparent magnitude (V) | 6.506 [2] + 14.10 [3] |
Characteristics | |
Spectral type | G1V [4] + M4V [5] |
B−V color index | 0.557 [2] |
Astrometry | |
Radial velocity (Rv) | −68.50±0.22 [6] km/s |
Proper motion (μ) |
RA: −137.102±0.097
[1]
mas/
yr Dec.: −143.204±0.074 [1] mas/ yr |
Parallax (π) | 20.9210 ± 0.0508 mas [1] |
Distance | 155.9 ± 0.4
ly (47.8 ± 0.1 pc) |
Absolute magnitude (MV) | 3.055 [2] |
Details [2] | |
A | |
Mass | 1.35±0.045 M☉ |
Radius | 2.12±0.12 R☉ |
Luminosity | 5.07 [6] L☉ |
Surface gravity (log g) | 3.92±0.08 cgs |
Temperature | 5,969±44 K |
Metallicity [Fe/H] | +0.17±0.04 dex |
Rotational velocity (v sin i) | 5.05±0.50 km/s |
Age | 2.8+0.1 −0.2 [6] Gyr |
B | |
Mass | 0.59 [5] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
HD 156846 is a binary star [5] system in the equatorial constellation of Ophiuchus, positioned a degree SSE of Messier 9. [8] It has a yellow hue and is just barely bright enough to be visible to the naked eye with an apparent visual magnitude of 6.5. [2] The system is located at a distance of 156 light years from the Sun based on parallax. [1] It is drifting closer with a radial velocity of −68.5 km/s, and is predicted to come to within 85.0 light-years in about 476,000 years. [6]
The primary, component A, is a G-type star with a stellar classification of G1V. [4] The absolute visual magnitude of this star is 1.13 magnitudes above the main sequence, indicating it has evolved slightly off the main sequence. [2] It has 1.35 times the mass of the Sun and 2.12 times the Sun's radius. [2] The star is an estimated 2.8 [6] billion years old and is spinning with a projected rotational velocity of 5 km/s. [2] It is radiating five [6] times the luminosity of the Sun from its photosphere at an effective temperature of 5,969 K. [2]
The magnitude 14.4 secondary companion, component B, was discovered by the American astronomer R. G. Aitken in 1910. [3] It lies at an angular separation of 5.1 ″ from the primary, corresponding to a projected separation of 250 AU. This is a red dwarf with a class of M4V and has an estimated 59% of the Sun's mass. [5]
On 26 October 2007, a planet HD 156846 b was found orbiting the primary star by Tamuz, using the radial velocity method. [9] It has an orbital period of 0.98 years and a large eccentricity of 0.85. The estimated mass of this object is, at a minimum, 10.6 times the mass of Jupiter. If it were following the same orbit within the Solar System, it would have a perihelion within the orbit of Mercury and an aphelion outside the orbit of Mars. [2]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥10.57±0.29 MJ | 1.096±0.021 | 359.5546±0.0071 | 0.84785±0.00050 | — | — |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 17h 20m 34.31093s [1] |
Declination | −19° 20′ 01.4944″ [1] |
Apparent magnitude (V) | 6.506 [2] + 14.10 [3] |
Characteristics | |
Spectral type | G1V [4] + M4V [5] |
B−V color index | 0.557 [2] |
Astrometry | |
Radial velocity (Rv) | −68.50±0.22 [6] km/s |
Proper motion (μ) |
RA: −137.102±0.097
[1]
mas/
yr Dec.: −143.204±0.074 [1] mas/ yr |
Parallax (π) | 20.9210 ± 0.0508 mas [1] |
Distance | 155.9 ± 0.4
ly (47.8 ± 0.1 pc) |
Absolute magnitude (MV) | 3.055 [2] |
Details [2] | |
A | |
Mass | 1.35±0.045 M☉ |
Radius | 2.12±0.12 R☉ |
Luminosity | 5.07 [6] L☉ |
Surface gravity (log g) | 3.92±0.08 cgs |
Temperature | 5,969±44 K |
Metallicity [Fe/H] | +0.17±0.04 dex |
Rotational velocity (v sin i) | 5.05±0.50 km/s |
Age | 2.8+0.1 −0.2 [6] Gyr |
B | |
Mass | 0.59 [5] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
HD 156846 is a binary star [5] system in the equatorial constellation of Ophiuchus, positioned a degree SSE of Messier 9. [8] It has a yellow hue and is just barely bright enough to be visible to the naked eye with an apparent visual magnitude of 6.5. [2] The system is located at a distance of 156 light years from the Sun based on parallax. [1] It is drifting closer with a radial velocity of −68.5 km/s, and is predicted to come to within 85.0 light-years in about 476,000 years. [6]
The primary, component A, is a G-type star with a stellar classification of G1V. [4] The absolute visual magnitude of this star is 1.13 magnitudes above the main sequence, indicating it has evolved slightly off the main sequence. [2] It has 1.35 times the mass of the Sun and 2.12 times the Sun's radius. [2] The star is an estimated 2.8 [6] billion years old and is spinning with a projected rotational velocity of 5 km/s. [2] It is radiating five [6] times the luminosity of the Sun from its photosphere at an effective temperature of 5,969 K. [2]
The magnitude 14.4 secondary companion, component B, was discovered by the American astronomer R. G. Aitken in 1910. [3] It lies at an angular separation of 5.1 ″ from the primary, corresponding to a projected separation of 250 AU. This is a red dwarf with a class of M4V and has an estimated 59% of the Sun's mass. [5]
On 26 October 2007, a planet HD 156846 b was found orbiting the primary star by Tamuz, using the radial velocity method. [9] It has an orbital period of 0.98 years and a large eccentricity of 0.85. The estimated mass of this object is, at a minimum, 10.6 times the mass of Jupiter. If it were following the same orbit within the Solar System, it would have a perihelion within the orbit of Mercury and an aphelion outside the orbit of Mars. [2]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥10.57±0.29 MJ | 1.096±0.021 | 359.5546±0.0071 | 0.84785±0.00050 | — | — |