HD 9446

HD 9446 is a star located about 164[1] light-years away in the constellation of Triangulum, near the southwestern constellation border with Pisces. This object can be viewed with binoculars or a telescope, but it is too faint to be seen with the naked eye at its apparent visual magnitude of 8.35.[2] It is drifting further away from the Sun with a radial velocity of +21 km/s.[2]

HD 9446
Observation data
Epoch J2000      Equinox J2000
Constellation Triangulum
Right ascension 01h 33m 20.1848s[1]
Declination +29° 15 54.5390[1]
Apparent magnitude (V) 8.35[2]
Characteristics
Spectral type G5V[3]
B−V color index +0.680±0.015[2]
Astrometry
Radial velocity (Rv)+21.2±3.1[2] km/s
Proper motion (μ) RA: 190.249±0.140[1] mas/yr
Dec.: −53.650±0.201[1] mas/yr
Parallax (π)19.8336 ± 0.1376[1] mas
Distance164 ± 1 ly
(50.4 ± 0.3 pc)
Absolute magnitude (MV)4.76[2]
Details[3]
Mass1.00±0.10 M
Radius1.00 R
Luminosity1.1 L
Surface gravity (log g)4.53±0.16 cgs
Temperature5,793±22 K
Metallicity [Fe/H]0.09±0.05 dex
Rotational velocity (v sin i)4±1 km/s
Age2.0±1.5[4] Gyr
Other designations
BD+28°253, HD 9446, HIP 7245, SAO 74788[5]
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia
data

This object is a G-type main sequence star with a stellar classification of G5V.[3] The physical properties this star appear similar to the Sun, making it a candidate solar analog. However, the measured abundance of elements with more mass than helium is outside the accepted range.[6] It is roughly two billion years in age and has an active chromosphere. The amount of activity measured in the chromosphere corresponds to a star with a rotation period of about 10 days.[3]

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

The HD 9446 planetary system[3][7]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b  0.687±0.0056 MJ 0.1892±0.0065 30.0608+0.0034
−0.0033
0.20±0.06
c  1.71±0.13 MJ 0.646±0.022 189.6±0.13 0.06±0.06

See also

  • List of extrasolar planets

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. Gaia DR2 record for this source at VizieR.
  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. 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. Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951.
  5. "HD 9446". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-10.
  6. 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: A98, arXiv:1007.5351, Bibcode:2010A&A...522A..98M, doi:10.1051/0004-6361/201014741
  7. Hill, Michelle L.; Mocnik, Teo; Kane, Stephen R.; Henry, Gregory W.; Pepper, Joshua; Hinkel, Natalie R.; Dalba, Paul A.; Fulton, Benjamin J.; Stassun, Keivan G.; Rosenthal, Lee J.; Howard, Andrew W.; Howell, Steve B.; Everett, Mark E.; Boyajian, Tabetha S.; Fischer, Debra A.; Rodriguez, Joseph E.; Beatty, Thomas G.; James, David J. (2020). "Orbital Refinement and Stellar Properties for the HD 9446, HD 43691, and HD 179079 Planetary Systems". arXiv:2003.02385 [astro-ph.EP].

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