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]

HD 164427
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
Distance139 ± 1 ly
(42.6 ± 0.3 pc)
Absolute magnitude (MV)3.98±0.06[4]
Details
Mass1.125+0.063
−0.024[5] M☉
Radius1.40+0.05
−0.06[5] R☉
Luminosity2.33[2] L☉
Surface gravity (log g)4.24+0.03
−0.04[5] cgs
Temperature5,876[3] K
Metallicity [Fe/H]0.11±0.03[6] dex
Age6.6+1.3
−0.9[4] Gyr
Other designations
CD−59° 6780, GJ 700, HD 164427, HIP 88531, SAO 245217[7]
Database references
SIMBADdata

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
HD 164427 b
Discovery
Discovered byTinney et al.
Discovery siteAustralia
Discovery date2001
Doppler Spectroscopy
Orbital characteristics
0.46 AU (69,000,000 km)
Eccentricity0.55
108.55 d
2,451,189.3
55.2
Semi-amplitude1398.5
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 the brown dwarf and the 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
    1. 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.
    2. 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.
    3. 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.
    4. 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.
    5. 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.
    6. 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.
    7. "HD 164427". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-02.
    8. 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.
    9. 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)
    10. 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.
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