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]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| 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 mas/yr[1] Dec.: −262.843 mas/yr[1] |
| Parallax (π) | 26.7476 ± 0.0217 mas[1] |
| 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 |
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 edit
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 edit
References edit
- ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e 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.
- ^ a b 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. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
- ^ a b Soubiran, C.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv:1804.09370. Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795. S2CID 52952408.
- ^ a b c d e f g h i Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
- ^ a b c d 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. arXiv:1912.08659. Bibcode:2020A&A...634A.136C. doi:10.1051/0004-6361/201936523. S2CID 209405391. A136.
- ^ "HD 47186". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-23.
- ^ 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, Bibcode:1998A&AS..128..457W, doi:10.1051/aas:1998157
- ^ a b 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. arXiv:0812.1608. Bibcode:2009A&A...496..527B. doi:10.1051/0004-6361:200810669. S2CID 117778593.
Further reading edit
- 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. arXiv:0903.3597. Bibcode:2009ApJ...695L.181K. doi:10.1088/0004-637X/695/2/L181.
- "HD 47186". Exoplanets. Archived from the original on 2012-03-18. Retrieved 2008-12-16.