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 | G5IV-V[2] |
| B−V color index | 0.699 ± 0.001 |
| Astrometry | |
| Radial velocity (Rv) | 27.9 ± 0.2 km/s |
| Proper motion (μ) | RA: 87.14 ± 0.56[1] mas/yr Dec.: -55.92 ± 0.46[1] mas/yr |
| Parallax (π) | 15.57 ± 0.71[1] mas |
| Distance | 209 ± 10 ly (64 ± 3 pc) |
| Absolute magnitude (MV) | 3.07[2] |
| 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 209 light years[1] 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 previously reported additional object (HD 154857 c) was confirmed to have planetary nature in January 2014.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >2.24±0.05 MJ | 1.291±0.008 | 408 ± 0.5 | 0.46 ± 0.02 | — | — |
| c | ≥2.6 MJ | 5.36 | ~3470 | 0.06 | — | — |
See also
References
- 1 2 3 4 5 6 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 - 1 2 3 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.
- 1 2 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.
- 1 2 The Anglo-Australian Planet Search. XXIII. Two New Jupiter Analogs: Robert A. Wittenmyer, Jonathan Horner, C.G. Tinney, R.P. Butler, H.R.A. Jones, Mikko Tuomi, G.S. Salter, B.D. Carter, F. Elliott Koch, S.J. O'Toole, J. Bailey, D. Wright
External links
- "HD 154857". The Extrasolar Planets Encyclopaedia. Retrieved 2008-07-21.
- http://planetquest.jpl.nasa.gov
Coordinates: 
17h 11m 15.7219s, −56° 40′ 50.865″
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