HD 156668 b
| Exoplanet | List of exoplanets | |
|---|---|---|
| Parent star | ||
| Star | HD 156668 | |
| Constellation | Hercules | |
| Right ascension | (α) | 17h 17m 40s |
| Declination | (δ) | +29° 13′ 38″ |
| Apparent magnitude | (mV) | 8.42 |
| Distance | 78.5 ± 2.0 ly (24.1 ± 0.6 pc) | |
| Spectral type | K2V | |
| Physical characteristics | ||
| Minimum mass | (m sin i) | 3.1 ± 0.4[1] M⊕ |
| Orbital elements | ||
| Semi-major axis | (a) | 0.04998 ± 0.00083[2] AU |
| Eccentricity | (e) | 0.000[1] |
| Orbital period | (P) | 4.6455 ± 0.0011[2] d |
| Argument of periastron |
(ω) | 0[1]° |
| Time of conjunction | (Tc) | 2454718.57 ± 0.11[2] JD |
| Semi-amplitude | (K) | 1.89 ± 0.26 [2] m/s |
| Discovery information | ||
| Discovery date | 2010-01-06 | |
| Discoverer(s) | Howard et al. | |
| Discovery method | Doppler Spectroscopy | |
| Discovery site | Keck Observatory | |
| Discovery status | Submitted | |
| Database references | ||
| Extrasolar Planets Encyclopaedia | data | |
| SIMBAD | data | |
| Exoplanet Archive | data | |
| Open Exoplanet Catalogue | data | |
HD 156668 b is an extrasolar planet orbiting the star HD 156668 78.5 light-years away in the constellation Hercules. It has a minimum mass of 3.1 Earth masses. At the time of discovery it was the second least massive planet discovered by the radial velocity method, subject to the mass/inclination degeneracy that affects radial velocity measurements.[3] The only radial velocity planet less massive than this planet is Gliese 581 e, which was discovered on April 21, 2009, and has a minimum mass of 1.94 Earth masses. In addition to this, it has the lowest semi-amplitude, or the speed of the stellar wobble caused by planet's gravity tugging on the star determined by radial velocity, at 2.2 m/s.[3] This planet was discovered on January 6, 2010; it is the 8th planet discovered in 2010 after the first five planets detected by Kepler on January 4 and two planets around HD 9446 on January 5.
References
- 1 2 3 Dawson, Rebekah I.; Fabrycky, Daniel C. (2010). "Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e". The Astrophysical Journal. 722 (1): 937–953. Bibcode:2010ApJ...722..937D. arXiv:1005.4050
. doi:10.1088/0004-637X/722/1/937. - 1 2 3 4 Andrew W. Howard; John Asher Johnson; Geoffrey W. Marcy; Debra A. Fischer; Jason T. Wright; Gregory W. Henry; Howard Isaacson; Jeff A. Valenti; Jay Anderson; Nikolai E. Piskunov (2010). "The NASA-UC Eta-Earth Program: II. A Planet Orbiting HD 156668 with a Minimum Mass of Four Earth Masses". arXiv:1003.3444v1 [astro-ph.EP].
- 1 2 "Second Smallest Exoplanet Found To Date At Keck". W.M. Keck Observatory. 2010-01-07. Retrieved 2010-01-07.