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]
| 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 |
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]
Planetary system
editOn 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 | — | — |
See also
editReferences
edit- ^ a b c d e f 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.
- ^ a b c d e f g h i j k Kane, Stephen R.; et al. (May 2011). "Improved Orbital Parameters and Transit Monitoring for HD 156846b". The Astrophysical Journal. 733 (1): 7. arXiv:1103.4127. Bibcode:2011ApJ...733...28K. doi:10.1088/0004-637X/733/1/28. S2CID 13001033. 28.
- ^ a b Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
- ^ a b Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Vol. 4. Bibcode:1988mcts.book.....H.
- ^ a b c d Fontanive, C.; et al. (June 2019). "A high binary fraction for the most massive close-in giant planets and brown dwarf desert members". Monthly Notices of the Royal Astronomical Society. 485 (4): 4967–4996. arXiv:1903.02332. Bibcode:2019MNRAS.485.4967F. doi:10.1093/mnras/stz671. S2CID 84180618.
- ^ a b c d e f 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.
- ^ "HD 156846". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-13.
- ^ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 3. Sky Publishing Corporation and the European Space Agency. ISBN 0-933346-84-0.
- ^ Tamuz, O.; et al. (2008). "The CORALIE survey for southern extra-solar planets XV. Discovery of two eccentric planets orbiting HD 4113 and HD 156846". Astronomy and Astrophysics. 480 (3): L33–L36. arXiv:0710.5028. Bibcode:2008A&A...480L..33T. doi:10.1051/0004-6361:20078737. S2CID 11350536.