HD 164427
HD 164427 is a star with a brown dwarf companion in the southern constellation of Pavo. It has an apparent visual magnitude of 6.88,[2] placing it just below the nominal limit for visibility with the typical naked eye. The annual parallax shift of 23.5 mas[1] yields a distance estimate of 42.6 light years. It is moving further from the Earth with a heliocentric radial velocity of +3.4 km/s.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pavo |
| Right ascension | 18h 04m 42.58968s[1] |
| Declination | −59° 12′ 34.4678″[1] |
| Apparent magnitude (V) | 6.88[2] |
| Characteristics | |
| Spectral type | G0+V[3] |
| B−V color index | 0.624±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | +3.40±0.25[1] km/s |
| Proper motion (μ) | RA: −196.087[1] mas/yr Dec.: −51.219[1] mas/yr |
| Parallax (π) | 23.4516 ± 0.1836[1] mas |
| Distance | 139 ± 1 ly (42.6 ± 0.3 pc) |
| Absolute magnitude (MV) | 3.98±0.06[4] |
| Details | |
| Mass | 1.125+0.063 −0.024[5] M☉ |
| Radius | 1.40+0.05 −0.06[5] R☉ |
| Luminosity | 2.33[2] L☉ |
| Surface gravity (log g) | 4.24+0.03 −0.04[5] cgs |
| Temperature | 5,876[3] K |
| Metallicity [Fe/H] | 0.11±0.03[6] dex |
| Age | 6.6+1.3 −0.9[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an inactive[8] G-type main-sequence star given a stellar classification of G0+V by Gray et al. (2006),[3] although Evans et al. (1964) classified it as a subgiant star with luminosity class IV.[8] It is 6.6 billion years old with 1.125 times the mass of the Sun and 1.40 times the Sun's radius.[5] The star is somewhat over-luminous for its class,[8] radiating 2.33[2] times the Sun's luminosity from its photosphere at an effective temperature of 5,876 K.[3]
In 2001, a brown dwarf candidate companion was announced by Anglo-Australian Planet Search program. It was detected by the Doppler velocity technique with an echelle spectrograph attached to the 3.92m Anglo-Australian Telescope.[8] A magnitude 12.60 companion star designated HD 164427 B lies at an angular separation of 28.90″ along a position angle of 336°, as of 2010.[9] This is a suspected common proper motion companion with 52% of the Sun's mass[10] and a physical separation of as much as 1,090 AU.[8]
HD 164427 b
| Discovery | |
|---|---|
| Discovered by | Tinney et al. |
| Discovery site | Australia |
| Discovery date | 2001 |
| Doppler Spectroscopy | |
| Orbital characteristics | |
| 0.46 AU (69,000,000 km) | |
| Eccentricity | 0.55 |
| 108.55 d | |
| 2,451,189.3 | |
| 55.2 | |
| Semi-amplitude | 1398.5 |
| Physical characteristics | |
Mean radius | >1.4 RJ |
| Mass | >46 MJ |
HD 164427 b is a brown dwarf with a minimum mass of 46 times that of Jupiter. It orbits at nearly half an astronomical unit or Earth-to-Sun distance away from its star (HD 164427). The angular separation between a brown dwarf and a yellow dwarf as viewed from Earth is 11.76 Milliarcseconds. It takes 108.55 Earth days to orbit eccentrically around HD 164427. It has a very high semi-amplitude of almost 1400 m/s, because this is a very massive object which exerts strong gravitational pull on its tugging star.[8]
References
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
- 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.
- Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
- Holmberg, J.; et al. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics Supplement Series. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191.
- Takeda, Genya; et al. (February 2007). "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog". The Astrophysical Journal Supplement Series. 168 (2): 297–318. arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763.
- Gáspár, András; et al. (August 2016). "The Correlation between Metallicity and Debris Disk Mass". The Astrophysical Journal. 826 (2): 14. arXiv:1604.07403. Bibcode:2016ApJ...826..171G. doi:10.3847/0004-637X/826/2/171. 171.
- "HD 164427". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-02.
- Tinney, C. G.; et al. (2001). "First Results from the Anglo-Australian Planet Search: A Brown Dwarf Candidate and a 51 Peglike Planet". The Astrophysical Journal. 551 (1): 507–511. arXiv:astro-ph/0012204. Bibcode:2001ApJ...551..507T. doi:10.1086/320097.
- Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Cite journal requires
|journal=(help) - Tokovinin, Andrei (April 2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal. 147 (4): 14. arXiv:1401.6827. Bibcode:2014AJ....147...87T. doi:10.1088/0004-6256/147/4/87. 87.
External links
- "NLTT 45831 -- High proper-motion Star". SIMBAD. Retrieved December 21, 2007.