HD 7924
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 01h 21m 59.11s[1] |
| Declination | +76° 42′ 37.0″[1] |
| Apparent magnitude (V) | 7.185 |
| Characteristics | |
| Spectral type | K0V |
| Apparent magnitude (B) | 8.005 |
| Apparent magnitude (J) | 5.618 |
| Apparent magnitude (H) | 5.231 |
| Apparent magnitude (K) | 5.159 |
| B−V color index | 0.820 |
| Variable type | none |
| Astrometry | |
| Radial velocity (Rv) | –22.7 km/s |
| Proper motion (μ) | RA: –34.23 ± 0.43[1] mas/yr Dec.: –33.28 ± 0.48[1] mas/yr |
| Parallax (π) | 59.49 ± 0.46 mas[1] |
| Distance | 54.8 ± 0.4 ly (16.8 ± 0.1 pc) |
| Absolute magnitude (MV) | 6.056 |
| Details | |
| Mass | 0.81 ± 0.01[2] M☉ |
| Radius | 0.74 ± 0.01[2] R☉ |
| Luminosity | 0.364 ± 0.001[2] L☉ |
| Surface gravity (log g) | 4.6 ± 0.01[2] cgs |
| Temperature | 5216 ± 13[2] K |
| Metallicity | -0.15 ± 0.03 |
| Age | 3.0 ± 1.8[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
HD 7924 is a 7th magnitude K-type main sequence star located approximately 55 light years away in the constellation Cassiopeia. This star is smaller, cooler, dimmer, and less massive than our Sun. Also its metal content is about seven-tenths as much as the Sun. In 2009, a super-Earth exoplanet was found in orbit around the star.[3] In 2015, two more planets were discovered, and the mass of the original planet was revised downwards slightly.[4][5] It is possible that planets c and d are in the 8:5 mean motion resonance.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥8.68 ± 0.52 M🜨 | 0.05664 ± 0.00068 | 5.39792 ± 0.00025 | 0.058 +0.056 −0.040 |
— | — |
| c | ≥7.86 ± 0.72 M🜨 | 0.1134 ± 0.0014 | 15.299 ± 0.0033 | 0.098 +0.096 −0.069 |
— | — |
| d | ≥6.44 ± 0.79 M🜨 | 0.1551 ± 0.0019 | 24.451 ± 0.016 | 0.21 +0.13 −0.12 |
— | — |
See also
References
- ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
- ^ a b c d e f 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.
- ^ Howard, Andrew W.; et al. (2009). "The NASA-UC Eta-Earth Program. I. A Super-Earth Orbiting HD 7924". The Astrophysical Journal. 696 (1): 75–83. arXiv:0901.4394. Bibcode:2009ApJ...696...75H. doi:10.1088/0004-637X/696/1/75.
- ^ http://newscenter.berkeley.edu/2015/04/28/robotic-telescope-discovers-three-super-earth-planetary-neighbors/
- ^ a b Fulton, Benjamin J.; et al. (2015). "Three Super-Earths Orbiting HD 7924". The Astrophysical Journal. 805 (2): 175. arXiv:1504.06629. Bibcode:2015ApJ...805..175F. doi:10.1088/0004-637X/805/2/175.
- ^ Kane, Stephen R. (2016). "Resolving Close Encounters: Stability in the HD 5319 and HD 7924 Planetary Systems". The Astrophysical Journal. 799 (1). 105. arXiv:1411.5374. Bibcode:2016ApJ...830..105K. doi:10.3847/0004-637X/830/2/105.
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