View source for Astronomy:38 Virginis

{{Short description|F-type main sequence star in the constellation Virgo}}
{{Starbox begin 
| name = [[Astronomy:Flamsteed designation|38 Virginis]]
}}
{{Starbox observe 
| epoch = J2000.0
| constell = [[Astronomy:Virgo (constellation)|Virgo]]
| ra = {{RA|12|53|11.1564}}<ref name="Gaia DR2"/> 
| dec = {{DEC|−03|33|11.1482}}<ref name="Gaia DR2"/>
| appmag_v = 6.11
}} 
{{Starbox character 
| class = F6V<ref name="Borgniet2017"/>
| b-v = 0.49<ref name="Borgniet2017"/>
}} 
{{Starbox astrometry 
| radial_v = 
| prop_mo_ra = {{val|−262.638|0.113}}<ref name="Gaia DR2"/>
| prop_mo_dec = {{val|−3.853|0.100}}<ref name="Gaia DR2"/>
| parallax = 30.0702
| p_error = 0.0541
| parallax_footnote = <ref name="Gaia DR2"/>
| absmag_v = 6.11
}} 
{{Starbox detail 
| mass = {{nowrap|1.18 ± 0.12<ref name="Borgniet2017"/>}}
| radius = {{nowrap|1.45 ± 0.07<ref name="Borgniet2017"/>}}
| temperature = 6557 ± 96<ref name="Borgniet2017"/>
| luminosity = 3.48<ref group="note">From <math>\begin{smallmatrix}L=4 \pi R^2 \sigma T_{\rm eff}^4 \end{smallmatrix}</math>, where <math>\begin{smallmatrix}L \end{smallmatrix}</math> is the luminosity, <math>\begin{smallmatrix}R \end{smallmatrix}</math> is the radius, <math>\begin{smallmatrix}T_{\rm eff}\end{smallmatrix}</math> is the effective surface temperature and <math>\begin{smallmatrix}\sigma \end{smallmatrix}</math> is the [[Physics:Stefan–Boltzmann constant|Stefan–Boltzmann constant]].</ref>
| metal_fe = 0.07<ref name="Borgniet2017"/>
| rotation = 
| age_gyr = {{val|1.9|0.6|0.7}}<ref name="Borgniet2017"/>
}}
{{Starbox catalogue 
| names = {{odlist | BD=−02 3593 | HD=111998 | HIP=62875 | HR=4891 | WDS=J12532-0333AB }}<ref name="Simbad"/>
}}
{{Starbox reference
| Simbad = 38+Virginis
}}
{{Starbox end}}  
'''38 Virginis''' is an F-type main sequence star in the [[Astronomy:Constellation|constellation]] of [[Astronomy:Virgo (constellation)|Virgo]].  It is around 108 [[Light year|light year]]s distant from the [[Astronomy:Earth|Earth]].<ref name="Borgniet2017"/><ref name="Gaia DR2"/>

==Nomenclature==
The name 38 Virginis derives from the star being the 38th star in order of [[Right ascension|right ascension]] catalogued in the constellation Virgo by Flamsteed in his star catalogue. The designation ''b'' of 38 Virginis b derives from the order of discovery and is given to the first planet orbiting a given star, followed by the other lowercase letters of the alphabet.<ref name="planetnaming">{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |last1=Hessman |first1=F. V. |last2=Dhillon |first2=V. S. |last3=Winget |first3=D. E. |last4=Schreiber |first4=M. R. |last5=Horne |first5=K. |last6=Marsh |first6=T. R. |last7=Guenther |first7=E. |last8=Schwope |first8=A. |last9=Heber |first9=U. |eprint=1012.0707|class=astro-ph.SR }}</ref> In the case of 38 Virginis, only one was discovered, which was designated ''b''.<ref name="Borgniet2017"/>

==Stellar characteristics==
38 Virginis is an F-type main sequence star that is approximately 118% the mass of and 145% the radius of the [[Astronomy:Sun|Sun]]. It has a temperature of 6557 K and is about 1.9 billion years old. In comparison, the [[Astronomy:Sun|Sun]] is about 4.6 billion years old<ref>{{cite web |url=http://www.universetoday.com/18237/how-old-is-the-sun/ |title=How Old is the Sun? |author=Fraser Cain |date=16 September 2008 |publisher=Universe Today |access-date=19 February 2011}}</ref> and has a temperature of 5778 K.<ref>{{cite web |url=http://www.universetoday.com/18092/temperature-of-the-sun/ |title=Temperature of the Sun |author=Fraser Cain |date=15 September 2008 |publisher=Universe Today |access-date=19 February 2011}}</ref>

The star is metal-rich, with a [[Astronomy:Metallicity|metallicity]] ([Fe/H]) of 0.07 dex, or 117% the solar amount. Its luminosity ({{solar luminosity|link=y}}) is 3.48 times that of the Sun.

A companion star is cataloged in the CCDM at a separation of half an arcsecond.<ref>{{citation|author= J. Dommanget |display-authors=0 | title=Catalog of Components of Double & Multiple Stars |publisher=Observations et Travaux, Societe Astronomique de France |date= February 2002}}</ref>

==Planetary system==
{{OrbitboxPlanet begin
| table_ref = <ref name="Borgniet2017"/>
}}
{{OrbitboxPlanet
| exoplanet = [[Astronomy:38 Virginis b|b]]
| mass = 4.51 ± 0.5
| period = 825.9 ± 6.2
| semimajor =  1.82 ± 0.07 
| eccentricity = 0.03 ± 0.04
}}
{{Orbitbox end}}

The star is known to host one exoplanet, [[Astronomy:38 Virginis b|38 Virginis b]], discovered in 2016. This planet has a relatively low eccentricity out of any long-period giant exoplanet discovered, with an eccentricity of 0.03. The planet has a mass of around 4.5 times that of the planet [[Astronomy:Jupiter|Jupiter]].<ref name="Borgniet2017"/> Its orbit very likely puts it and any moons it may have in the [[Astronomy:Habitable zone|habitable zone]] of its star.{{cn|date=October 2018}}

==Notes==
<references group="note"/>

==References==
{{Reflist|refs=

<ref name="Borgniet2017">{{cite journal | title=Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample | url=https://www.aanda.org/articles/aa/full_html/2017/03/aa28805-16/aa28805-16.html | last1=Borgniet | first1=S. | last2=Lagrange | first2=A.-M. | last3=Meunier | first3=N. | last4=Galland | first4=F. | display-authors=1 | journal=Astronomy and Astrophysics | volume=599 | at=A57 | year=2017 | arxiv=1608.08257 | bibcode=2017A&A...599A..57B | doi=10.1051/0004-6361/201628805 | s2cid=118723455 }}</ref>

<ref name="Gaia DR2">{{cite DR2|3679242575447826432}}</ref>

<ref name="Simbad">{{cite simbad | title=38 Virginis | access-date=2018-10-19 }}</ref>

}}

{{Stars of Virgo|state=collapsed}}
{{Sky|12|53|11.3|-|03|33|11}}

{{DEFAULTSORT:38 Virginis}}
[[Category:F-type main-sequence stars]]
[[Category:Planetary systems with one confirmed planet]]
[[Category:Virgo (constellation)]]
[[Category:Double stars]]
[[Category:Durchmusterung objects]]
[[Category:Flamsteed objects|Virginis, 38]]
[[Category:Henry Draper Catalogue objects|111998]]
[[Category:Hipparcos objects|062875]]
[[Category:Bright Star Catalogue objects|4891]]

{{Sourceattribution|38 Virginis}}