Astronomy:HD 156846
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas |
| 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 astronomical unit|AU. This is a red dwarf with a class of M4V and has an estimated 59% of the Sun's mass.[5]
Planetary system
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 | — | — |
See also
- HD 4113
- List of extrasolar planets
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Kane, Stephen R. et al. (May 2011). "Improved Orbital Parameters and Transit Monitoring for HD 156846b". The Astrophysical Journal 733 (1): 7. doi:10.1088/0004-637X/733/1/28. 28. Bibcode: 2011ApJ...733...28K.
- ↑ 3.0 3.1 Mason, B. D. et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.
- ↑ 4.0 4.1 Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. 4. Bibcode: 1988mcts.book.....H.
- ↑ 5.0 5.1 5.2 5.3 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. doi:10.1093/mnras/stz671. Bibcode: 2019MNRAS.485.4967F.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ "HD 156846". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+156846.
- ↑ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. 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. doi:10.1051/0004-6361:20078737. Bibcode: 2008A&A...480L..33T. http://www.aanda.org/articles/aa/full/2008/12/aa8737-07/aa8737-07.html.
Coordinates: 
17h 20m 34.3100s, −19° 20′ 01.486″
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