HD 9446

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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

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]

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. ^ a b c d e f 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. ^ a b c d e f 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. S2CID 119257644.
  3. ^ a b c d e f Hébrard, Guillaume; Bonfils, Xavier; Ségransan, Damien; Moutou, Claire; Delfosse, Xavier; Bouchy, François; Boisse, Isabelle; Arnold, Luc (2010). "The SOPHIE Search for Northern Extrasolar Planets: II. A Multi-planet System Around HD 9446". Astronomy & Astrophysics. 513: A69. arXiv:1001.0682. Bibcode:2010A&A...513A..69H. doi:10.1051/0004-6361/200913790. S2CID 119306916.
  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. S2CID 54555839.
  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, S2CID 118481647
  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". The Astronomical Journal. 159 (5): 197. arXiv:2003.02385. Bibcode:2020AJ....159..197H. doi:10.3847/1538-3881/ab7d33. S2CID 212414679.

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

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