Astronomy:HD 47186
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 36m 08.788s[1] |
| Declination | −27° 37′ 20.27″[1] |
| Apparent magnitude (V) | 7.63[2] |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | G6V[3] |
| B−V color index | 0.714±0.002[2] |
| Astrometry | |
| Radial velocity (Rv) | 4.238±0.0003[4] km/s |
| Proper motion (μ) | RA: 21.582[1] mas/yr Dec.: −262.843[1] mas/yr |
| Parallax (π) | 26.7476 ± 0.0217[1] mas |
| Distance | 121.94 ± 0.10 ly (37.39 ± 0.03 pc) |
| Absolute magnitude (MV) | 4.64[2] |
| Details | |
| Mass | 1.05±0.01[5] M☉ |
| Radius | 1.12±0.01[5] R☉ |
| Luminosity | 1.219±0.005[5] L☉ |
| Surface gravity (log g) | 4.35±0.01[5] cgs |
| Temperature | 5,736±21[5] K |
| Metallicity [Fe/H] | 0.23[6] dex |
| Rotational velocity (v sin i) | 1.953[6] km/s |
| Age | 5.5±0.6[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
HD 47186 is a star with a pair of orbiting exoplanets in the southern constellation of Canis Major. The system is located at a distance of 122 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 4.2 km/s.[4] Although it has an absolute magnitude of 4.64,[2] at the distance of this system the apparent visual magnitude is 7.63;[2] too faint to be seen with the naked eye. It has a high proper motion, traversing the celestial sphere at an angular rate of 0.272″·yr−1.[8]
The spectrum of HD 47186 matches a G-type main-sequence star with a stellar classification of G6V.[3] It is an estimated 5.5[5] billion years old and is spinning with a projected rotational velocity of 2 km/s.[6] The star has 5% greater mass and a 12% larger girth compared to the Sun.[5] The abundance of iron, a measure of the star's metallicity, is 1.7 times more than the Sun, making it metal-rich.[6] HD 47186 is radiating 1.2 times the luminosity of the Sun from its photosphere at an effective temperature of 5,736 K.[5]
Planetary system
Announced in June 2008, two extrasolar planets were discovered orbiting the star. Both planets are less massive than Jupiter. The inner planet HD 47186 b orbits close to the star and is termed a “hot Neptune”. The outer planet HD 47186 c orbits in a similar distance from the star as the asteroid Vesta, at around 2.4 AU. The inner planet orbits in a circular path while the outer planet orbits in an eccentric path.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥0.07167 MJ | 0.050 | 4.0845 ± 0.0002 | 0.038 ± 0.020 | — | — |
| c | ≥0.35061 MJ | 2.395 | 1353.6 ± 57.1 | 0.249 ± 0.073 | — | — |
See also
References
- ↑ 1.0 1.1 1.2 1.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Gray, R. O. et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 Soubiran, C. et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics 616: A7. doi:10.1051/0004-6361/201832795. Bibcode: 2018A&A...616A...7S.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Bonfanti, A. et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics 575: A18. doi:10.1051/0004-6361/201424951. Bibcode: 2015A&A...575A..18B. http://www.aanda.org/articles/aa/full_html/2015/03/aa24951-14/aa24951-14.html.
- ↑ 6.0 6.1 6.2 6.3 Costa Silva, A. R. et al. (February 2020). "Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur". Astronomy & Astrophysics 634: 10. doi:10.1051/0004-6361/201936523. A136. Bibcode: 2020A&A...634A.136C.
- ↑ "HD 47186". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+47186.
- ↑ Wroblewski, H.; Torres, C. (March 1998), "New proper motion determination of Luyten catalogue stars (LTT) with declination between -5° and -30° and right ascension between 0h and 13h 30m", Astronomy and Astrophysics Supplement 128: 457–458, doi:10.1051/aas:1998157, Bibcode: 1998A&AS..128..457W
- ↑ 9.0 9.1 Bouchy, François et al. (2009). "The HARPS Search for Southern Extra-solar Planets. XVII. Super-Earth and Neptune-mass Planets in Multiple Planet Systems HD 47186 and HD 181433". Astronomy and Astrophysics 496 (2): 527–31. doi:10.1051/0004-6361:200810669. Bibcode: 2009A&A...496..527B. http://www.aanda.org/articles/aa/full_html/2009/11/aa10669-08/aa10669-08.html.
Further reading
- Kopparapu, Ravi Kumar et al. (April 2009). "Stability of Additional Planets in and Around the Habitable Zone of the HD 47186 Planetary System". The Astrophysical Journal Letters 695 (2): L181–L184. doi:10.1088/0004-637X/695/2/L181. Bibcode: 2009ApJ...695L.181K.
- "HD 47186". Exoplanets. http://media4.obspm.fr/exoplanets/base/etoile.php?nom=HD+47186.
Coordinates: 
06h 36m 08.7880s, −27° 37′ 20.268″
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