HD 154857
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 11m 15.72s[1] |
| Declination | −56° 40′ 50.9″[1] |
| Apparent magnitude (V) | 7.25 |
| Characteristics | |
| Spectral type | G5V |
| B−V color index | 0.699 ± 0.001 |
| Astrometry | |
| Radial velocity (Rv) | 27.9 ± 0.2 km/s |
| Proper motion (μ) | RA: 87.19 ± 0.8 mas/yr Dec.: -55.37 ± 0.57 mas/yr |
| Parallax (π) | 14.59 ± 0.91 mas |
| Distance | 220 ± 10 ly (69 ± 4 pc) |
| Absolute magnitude (MV) | 7.9 |
| Details | |
| Mass | 1.17 (± 0.05) M☉ |
| Radius | 2.42 R☉ |
| Luminosity | 4.61 L☉ |
| Surface gravity (log g) | 5,579844548 g cgs |
| Temperature | 5445 K |
| Metallicity | -0.23 (± 0.03) % |
| Age | 8.98 G years |
| Equatorial [ g ] | 54,7 m/s2 |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Data sources: | |
| Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
HD 154857 is a yellow main-sequence star approximately 224 light years away in the constellation of Ara.
Planetary system
There is one confirmed and one unconfirmed planet discovered in 2004[2] and 2007[3] respectively. The confirmed planet HD 154857 b has mass >1.8 times that of Jupiter. It orbits the star 20% further than Earth-Sun distance, taking 409 days with 47% eccentricity. The unconfirmed planet HD 154857 c with unknown mass (probably around 18 Jupiter masses) takes at least 1900 days to orbit around the star with an orbital eccentricity exceeding 0.25.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >1.8 ± 0.4 MJ | 1.2 ± 0.2 | 409 ± 1 | 0.47 ± 0.02 | — | — |
| c (unconfirmed) | ≥18.4 MJ | ? | >1900 | ≥0.25 | — | — |
See also
References
- ^ a b 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
- ^ McCarthy, Chris; et al. (2004). "Multiple Companions to HD 154857 and HD 160691". The Astrophysical Journal. 617 (1): 575–579. arXiv:astro-ph/0409335. Bibcode:2004ApJ...617..575M. doi:10.1086/425214.
- ^ a b O'Toole, Simon J.; et al. (2007). "New Planets around Three G Dwarfs". The Astrophysical Journal. 660 (2): 1636–1641. arXiv:astro-ph/0702213. Bibcode:2007ApJ...660.1636O. doi:10.1086/513563.
External links
- "HD 154857". The Extrasolar Planets Encyclopaedia. Retrieved 2008-07-21.
- "HD 154857". Extrasolar Visions. Retrieved 2008-07-21.
- http://planetquest.jpl.nasa.gov
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