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]
| 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 |
| Distance | 164 ± 1 ly (50.4 ± 0.3 pc) |
| Absolute magnitude (MV) | 4.76[2] |
| Details[3] | |
| Mass | 1.00±0.10 M☉ |
| Radius | 1.00 R☉ |
| Luminosity | 1.1 L☉ |
| Surface gravity (log g) | 4.53±0.16 cgs |
| Temperature | 5,793±22 K |
| Metallicity [Fe/H] | 0.09±0.05 dex |
| Rotational velocity (v sin i) | 4±1 km/s |
| Age | 2.0±1.5[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| 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]
| 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
- 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.
- 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.
- 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.
- 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.
- "HD 9446". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-10.
- 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
- 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].