HD 9446

HD 9446
Observation data
Epoch J2000      Equinox J2000
Constellation Triangulum
Right ascension 01h 33m 20.1847s[1]
Declination +29° 15′ 54.539″[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: 190.343(28) mas/yr
Dec.: −53.675(31) mas/yr
Parallax (π)19.9200 ± 0.0413 mas[1]
Distance163.7 ± 0.3 ly
(50.2 ± 0.1 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

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 — —
  1. ^ a b c d Cite error: The named reference Gaia DR3 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference aaa513 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Bonfanti2015 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference aaa522 was invoked but never defined (see the help page).
  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.