HD 9446

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HD 9446
Observation data
Epoch J2000      Equinox J2000
Constellation Triangulum
Right ascension 01h 33m 20.18561s[1]
Declination +29° 15′ 54.5375″[1]
Apparent magnitude (V) 8.35[2]
Characteristics
Spectral type G5V[3]
U−B color index +0.14[2]
B−V color index +0.68[2]
Astrometry
Radial velocity (Rv) 20.2[4] km/s
Proper motion (μ) RA: 192.01[1] mas/yr
Dec.: –53.99[1] mas/yr
Parallax (π) 19.10 ± 1.06[1] mas
Distance 171 ± 9 ly
(52 ± 3 pc)
Details
Mass 1.00 ± 0.10[3] M
Radius 1.00[3] R
Luminosity 1.1[3] L
Surface gravity (log g) 4.53 ± 0.16[3] cgs
Temperature 5793 ± 22[3] K
Metallicity [Fe/H] 0.09 ± 0.05[3] dex
Rotational velocity (v sin i) 4 ± 1[3] km/s
Other designations
BD+28 253, HIP 7245, HD 9446, SAO 74788.
Database references
SIMBAD data
Exoplanet Archive data
Extrasolar Planets
Encyclopaedia
data

HD 9446 is a star located about 171 light-years away in the constellation of Triangulum. It is a G-type main sequence star with a stellar classification of G5V. The physical properties this star appear similar to the Sun, making it a candidate solar twin. However, the measured abundance of elements with more mass than helium is above the accepted range.[5] The amount of activity measured in the chromosphere corresponds to a star with a rotation period of about 10 days.[3]

Planetary system[edit]

On 5 January 2010, scientists announced the discovery of two planets orbiting around HD 9446.[3]

The HD 9446 planetary system[3]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ≥ 0.70 ± 0.06 MJ 0.189 ± 0.006 30.052 ± 0.027 0.20 ± 0.06
c ≥ 1.82 ± 0.17 MJ 0.654 ± 0.022 192.9 ± 0.9 0.06 ± 0.06

See also[edit]

References[edit]

  1. ^ a b c d e van Leeuwen, F. (November 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. 
  2. ^ a b c "LTT 10545 -- High proper-motion Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2011-12-13. 
  3. ^ a b c d e f g h i j k Hébrard, G. et al. (2010). "The SOPHIE search for northern extrasolar planets: II. A multi-planet system around HD 9446". Astronomy & Astrophysics 513. arXiv:1001.0682. Bibcode:2010A&A...513A..69H. doi:10.1051/0004-6361/200913790. 
  4. ^ Wilson, Ralph Elmer (1953). General catalogue of stellar radial velocities. Carnegie Institution of Washington. Bibcode:1953QB901.W495..... 
  5. ^ Meléndez, J. et al. (November 2010), "uvby-β photometry of solar twins . The solar colors, model atmospheres, and the Teff and metallicity scales", Astronomy and Astrophysics 522, arXiv:1007.5351, Bibcode:2010A&A...522A..98M, doi:10.1051/0004-6361/201014741 

Coordinates: Sky map 01h 33m 20s, +29° 15′ 55″