View source for HD 9446

{{Short description|Star with a planetary system in the constellation Triangulum}}
{{Starbox begin}}
{{Starbox observe
| epoch       = J2000
| constell    = [[Triangulum]]
| ra          = {{RA|01|33|20.1847}}<ref name="Gaia DR3"/>
| dec         = {{DEC|+29|15|54.539}}<ref name="Gaia DR3"/>
| appmag_v    = 8.35<ref name=Anderson2012/>
}}
{{Starbox character
| type        =
| class       = G5V<ref name=aaa513/>
| b-v         = {{Val|+0.680|0.015}}<ref name=Anderson2012/>
| u-b         =
| variable    =
}}
{{Starbox astrometry
| radial_v    = {{Val|+21.2|3.1}}<ref name=Anderson2012/>
| prop_mo_ra  = {{val|190.343|(28)}}
| prop_mo_dec = {{val|−53.675|(31)}}
| parallax    = 19.9200
| p_error     = 0.0413
| parallax_footnote = <ref name="Gaia DR3"/>
| absmag_v    = 4.76<ref name=Anderson2012/>
}}
{{Starbox detail
| mass        = {{Val|1.07|0.18}} <ref name=Hill/>
| radius      = {{val|0.984|0.01}} <ref name=Hill/>
| gravity     = {{Val|4.53|0.16}}<ref name=aaa513/>
| luminosity  = 1.1<ref name=aaa513/>
| temperature = {{Val|5793|22|fmt=commas}}<ref name=aaa513/>
| metal_fe    = {{Val|0.09|0.05}}<ref name=aaa513/>
| age_gyr     = {{Val|2.0|1.5}}<ref name="Bonfanti2015"/>
| rotational_velocity = {{Val|4|1}}
}}
{{Starbox catalog
| names = {{odlist | BD=+28°253 | HD=9446 | HIP=7245 | SAO=74788 }}<ref name=SIMBAD/>
}}
{{Starbox reference
| Simbad = HD+9446
| NSTED  = HD+9446
| EPE    = HD+9446
}}
{{Starbox end
}}
'''HD 9446''' is a [[star]] located about 164<ref name="Gaia DR3"/>&nbsp;[[light-year]]s away in the [[constellation]] of [[Triangulum]], near the southwestern constellation border with [[Pisces (constellation)|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.<ref name=Anderson2012/> It is drifting further away from the [[Sun]] with a [[radial velocity]] of +21&nbsp;km/s.<ref name=Anderson2012/>
This object is a [[G-type main sequence star]] with a [[stellar classification]] of G5V.<ref name=aaa513/> 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.<ref name=aaa522/> It is roughly two billion years in age and has an [[magnetic activity|active chromosphere]]. The amount of activity measured in the [[chromosphere]] corresponds to a star with a rotation period of about 10 days.<ref name=aaa513/>
On 5 January 2010, scientists announced the discovery of two [[extrasolar planet|planets]] orbiting around HD 9446.<ref name=aaa513/>
{{OrbitboxPlanet begin
| table_ref = <ref name=aaa513/><ref name=Hill/>
}}
{{OrbitboxPlanet
| exoplanet = [[HD 9446 b|b]]
| mass = ≥&nbsp;{{val|0.687|0.0056}}
| period = {{val|30.0608|0.0034|0.0033}}
| semimajor = {{val|0.1892|0.0065}}
| eccentricity = {{val|0.20|0.06}}
}}
{{OrbitboxPlanet
| exoplanet = [[HD 9446 c|c]]
| mass = ≥&nbsp;{{val|1.71|0.13}}
| period = {{val|189.6|0.13}}
| semimajor = {{val|0.646|0.022}}
| eccentricity = {{val|0.06|0.06}}
}}
{{Orbitbox end}}
== See also ==
* [[List of extrasolar planets]]
== References ==
{{reflist|refs=
<ref name=SIMBAD>{{cite simbad | title=HD 9446 | accessdate=2019-11-10}}</ref>
<ref name="Gaia DR3">{{Cite Gaia DR3|302956655074266112}}</ref>
<ref name=Anderson2012>{{cite journal
| last1=Anderson | first1=E. | last2=Francis | first2=Ch.
| title=XHIP: An extended hipparcos compilation
| journal=Astronomy Letters
| volume=38 | issue=5 | pages=331 | year=2012
| bibcode=2012AstL...38..331A | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>
<ref name=Hill>{{Cite journal |last1=Hill |first1=Michelle L. |last2=Mocnik |first2=Teo |last3=Kane |first3=Stephen R. |last4=Henry |first4=Gregory W. |last5=Pepper |first5=Joshua |last6=Hinkel |first6=Natalie R. |last7=Dalba |first7=Paul A. |last8=Fulton |first8=Benjamin J. |last9=Stassun |first9=Keivan G. |last10=Rosenthal |first10=Lee J. |last11=Howard |first11=Andrew W. |last12=Howell |first12=Steve B. |last13=Everett |first13=Mark E. |last14=Boyajian |first14=Tabetha S. |last15=Fischer |first15=Debra A. |date=2020-05-01 |title=Orbital Refinement and Stellar Properties for the HD 9446, HD 43691, and HD 179079 Planetary Systems |arxiv=2003.02385 |journal=The Astronomical Journal |volume=159 |issue=5 |pages=197 |doi=10.3847/1538-3881/ab7d33 |doi-access=free |issn=0004-6256}}</ref>
<ref name="Bonfanti2015">{{cite journal
| title=Revising the ages of planet-hosting stars
| url=http://www.aanda.org/articles/aa/full_html/2015/03/aa24951-14/aa24951-14.html
| last1=Bonfanti | first1=A. | last2=Ortolani | first2=S.
| last3=Piotto | first3=G. | last4=Nascimbeni | first4=V.
| display-authors=1 | journal=Astronomy and Astrophysics
| volume=575 | at=A18 | year=2015
| arxiv=1411.4302 | bibcode=2015A&A...575A..18B
| doi=10.1051/0004-6361/201424951 | s2cid=54555839
}}</ref>
<ref name=aaa513>{{cite journal
|doi=10.1051/0004-6361/200913790
|last1=Hébrard |first1=Guillaume
|last2=Bonfils |first2=Xavier
|last3=Ségransan |first3=Damien
|last4=Moutou |first4=Claire
|last5=Delfosse |first5=Xavier
|last6=Bouchy |first6=François
|last7=Boisse |first7=Isabelle
|last8=Arnold |first8=Luc
|date=2010
|title=The SOPHIE Search for Northern Extrasolar Planets: II. A Multi-planet System Around HD 9446
|journal=Astronomy & Astrophysics
|volume=513
|pages=A69
|url=http://www.aanda.org/articles/aa/full_html/2010/05/aa13790-09/aa13790-09.html
|bibcode=2010A&A...513A..69H
|arxiv=1001.0682
|s2cid=119306916 }}</ref>
<ref name=aaa522>{{citation
| last1=Meléndez | first1=J. | last2=Schuster | first2=W. J.
| last3=Silva | first3=J. S. | last4=Ramírez | first4=I.
| last5=Casagrande | first5=L. | last6=Coelho | first6=P.
| title=uvby-β photometry of solar twins. The solar colors, model atmospheres, and the Teff and metallicity scales
| display-authors=1 | journal=Astronomy and Astrophysics
| volume=522 | pages=A98 | date=November 2010
| bibcode=2010A&A...522A..98M | arxiv=1007.5351
| doi=10.1051/0004-6361/201014741
| s2cid=118481647 | url=https://zenodo.org/record/998268 }}</ref>
}}
{{Sky|01|33|20|+|29|15|55|53}}
{{HD 9446}}
{{Stars of Triangulum}}
[[Category:G-type main-sequence stars]]
[[Category:Planetary systems with two confirmed planets]]
[[Category:Triangulum]]
[[Category:Durchmusterung objects]]
[[Category:Henry Draper Catalogue objects|009446]]
[[Category:Hipparcos objects|007245]]