{{Short description|Star in the constellation Draco}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Draco constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=HD 193664 |x=70|y=450 }} | caption = Location of HD 193664 (circled in red) }} {{Starbox observe | epoch = J2000.0 | constell = [[Draco (constellation)|Draco]]<ref name=xhip/> | ra = {{RA|20|17|31.328}}<ref name=GaiaDR3/> | dec = {{DEC|+66|51|13.28}}<ref name=GaiaDR3/> | appmag_v = 5.93<ref name=mnras371_4_1793/> }} {{Starbox character | type = [[main sequence]]<ref name=GaiaDR3/> | class = G3&nbsp;V<ref name="ar55_1_31"/> | b-v = +0.58<ref name=mnras371_4_1793/> | u-b = +0.06<ref name=mnras371_4_1793/> | variable = }} {{Starbox astrometry | radial_v = −4.7<ref name="apj764_1_78"/> | prop_mo_ra = +468.684 | prop_mo_dec = +297.589 | pm_footnote = <ref name=GaiaDR3/> | parallax = 57.2041 | p_error = 0.0208 | parallax_footnote = <ref name=GaiaDR3/> | absmag_v = 4.69<ref name=xhip/> }} {{Starbox detail | mass = 1.04<ref name=luck2017/> | radius = 1.03<ref name=apjss168_2_297/> | luminosity = 1.1<ref name=luck2017/> | gravity = 4.45<ref name=luck2017/> | temperature = 5,922<ref name=luck2017/> | metal_fe = −0.13<ref name="apj764_1_78"/> | rotation = | rotational_velocity = 1.3<ref name=apj22159_1_141/> | age_gyr = 3.18<ref name=luck2017/> }} {{Starbox catalog | names = {{odlist | BD=+66°1281 | GJ=788 | HD=193664 | HIP=100017 | HR=7783 | SAO=18796 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = HD+193664 }} {{Starbox end}}

'''HD 193664''' is a star in the northern [[constellation]] of [[Draco (constellation)|Draco]]. HD 193664 is its [[Henry Draper Catalogue]] designation. With an [[apparent magnitude]] of 5.93,<ref name=mnras371_4_1793/> according to the [[Bortle Scale]] it is visible to the naked eye from suburban skies. [[Stellar parallax|Parallax]] measurements yield an estimated distance of 57&nbsp;[[light year]]s.<ref name=GaiaDR3/> It has a relatively large [[proper motion]] of 0.558 [[arc second]]s per year across the sky,<ref name=aj129_3_1483/> and is drifting closer to the Sun with a [[radial velocity]] of −4.7&nbsp;km/s.<ref name="apj764_1_78"/>

This star is considered a [[solar analog]]—meaning that it is [[Photometry (astronomy)|photometrically]] analogous to the Sun—and it displays no significant [[Variable star|variability]].<ref name=aat22_1_47/> It is a [[G-type main sequence star]] with a [[stellar classification]] of G3V.<ref name="ar55_1_31"/> Both the mass and radius of HD 193664 differ from those of the Sun by just a few percent, although it has a somewhat lower [[metallicity]].<ref name="apj764_1_78"/> It may be around the same age as the Sun, being an estimated 3.2 billion years old.<ref name=luck2017/> The [[effective temperature]] of the [[stellar atmosphere]] is 5,922&nbsp;K,<ref name=luck2017/> giving it the yellow-hued glow of a G-type star.<ref name=csiro/>

HD 193664 has been examined for signs of an [[infrared excess]] that could indicate the presence of a [[circumstellar disk]] of dust, but none has been found (as of 2012).<ref name=aa541_A40/> This is member of the [[thin disk population]] of stars that lie near the [[galactic plane]].<ref name="apj764_1_78"/>

== References == <references> <ref name=GaiaDR3>{{Cite Gaia DR3|2246581329639103872}}</ref>

<ref name=xhip>{{cite XHIP|100017}}</ref>

<ref name="ar55_1_31">{{citation | display-authors=1 | last1=Shenavrin | first1=V. I. | last2=Taranova | first2=O. G. | last3=Nadzhip | first3=A. E. | title=Search for and study of hot circumstellar dust envelopes | journal=Astronomy Reports | volume=55 | issue=1 | pages=31–81 | date=2011 | bibcode=2011ARep...55...31S | doi=10.1134/S1063772911010070 | s2cid=122700080 | postscript=. }}</ref>

<ref name="apj764_1_78">{{citation | display-authors=1 | last1=Ramírez | first1=I. | last2=Allende Prieto | first2=C. | last3=Lambert | first3=D. L. | title=Oxygen abundances in nearby FGK stars and the galactic chemical evolution of the local disk and halo | journal=The Astrophysical Journal | volume=764 | issue=1 | page=78 | date=February 2013 | doi=10.1088/0004-637X/764/1/78 | bibcode=2013ApJ...764...78R | arxiv=1301.1582 | s2cid=118751608 | postscript=. }}</ref>

<ref name=apjss168_2_297>{{citation | display-authors=1 | last1=Takeda | first1=Genya | last2=Ford | first2=Eric B. | last3=Sills | first3=Alison | last4=Rasio | first4=Frederic A. | last5=Fischer | first5=Debra A. | last6=Valenti | first6=Jeff A. | title=Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog | journal=The Astrophysical Journal Supplement Series | volume=168 | issue=2 | pages=297–318 | doi=10.1086/509763 | bibcode=2007ApJS..168..297T | arxiv=astro-ph/0607235 | date=February 2007 | s2cid=18775378 | postscript=. }}</ref>

<ref name=mnras371_4_1793>{{citation | last1=Karatas | first1=Y. | last2=Schuster | first2=W. J. | title=Metallicity and absolute magnitude calibrations for UBV photometry | journal=Monthly Notices of the Royal Astronomical Society | volume=371 | issue=4 | pages=1793–1812 | date=October 2006 | doi=10.1111/j.1365-2966.2006.10800.x | bibcode=2006MNRAS.371.1793K | postscript=. | doi-access=free}}</ref>

<ref name=aj129_3_1483>{{citation | last1=Lépine | first1=Sébastien | last2=Shara | first2=Michael M. | title=A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog) | journal=The Astronomical Journal | volume=129 | issue=3 | pages=1483–1522 | date=March 2005 | doi=10.1086/427854 | bibcode=2005AJ....129.1483L | postscript=. |arxiv = astro-ph/0412070 | s2cid=2603568 }}</ref>

<ref name=aa541_A40>{{citation | display-authors=1 | last1=Maldonado | first1=J. | last2=Eiroa | first2=C. | last3=Villaver | first3=E. | last4=Montesinos | first4=B. | last5=Mora | first5=A. | title=Metallicity of solar-type stars with debris discs and planets⋆ | journal=Astronomy & Astrophysics | volume=541 | id=A40 | pages=10 | date=May 2012 | doi=10.1051/0004-6361/201218800 | bibcode=2012A&A...541A..40M | postscript=. |arxiv = 1202.5884 | s2cid=46328823 }}</ref>

<ref name=aat22_1_47>{{citation | last1=Metlov | first1=V. G. | title=Photoelectric Observations of Bright Solar Type Stars | journal=Astronomical and Astrophysical Transactions | volume=22 | issue=1 | pages=47–50 | date=January 2003 | doi=10.1080/1055679021000020020 | bibcode=2003A&AT...22...47M | postscript=. }}</ref>

<ref name=apj22159_1_141>{{citation | last1=Valenti | first1=Jeff A. | last2=Fischer | first2=Debra A. | title=Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs | journal=The Astrophysical Journal Supplement Series | volume=159 | issue=1 | pages=141–166 |date=July 2005 | doi=10.1086/430500 | bibcode=2005ApJS..159..141V | postscript=. | doi-access=free }}</ref>

<ref name=csiro>{{citation | title=The Colour of Stars | date=December 21, 2004 | work=Australia Telescope, Outreach and Education | publisher=[[Commonwealth Scientific and Industrial Research Organisation]] | url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | access-date=2012-01-16 | postscript=. | archive-url=https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | archive-date=March 18, 2012 | url-status=dead }}</ref>

<ref name=luck2017>{{citation |postscript=. | title=Abundances in the Local Region II: F, G, and K Dwarfs and Subgiants | last1=Luck | first1=R. Earle | journal=The Astronomical Journal | volume=153 | issue=1 | id=21 | pages=19 | date=January 2017 | bibcode=2017AJ....153...21L | arxiv=1611.02897 | doi=10.3847/1538-3881/153/1/21 | s2cid=119511744 | doi-access=free }}</ref>

<ref name=SIMBAD>{{cite simbad | title=HD 193664 | access-date=2015-11-13 }}</ref> </references> {{Stars of Draco}}

[[Category:G-type main-sequence stars]] [[Category:Solar analogs]] [[Category:Draco (constellation)]] [[Category:Bright Star Catalogue objects|7783]] [[Category:Durchmusterung objects|BD+66 1281]] [[Category:Gliese and GJ objects|0788]] [[Category:Henry Draper Catalogue objects|193664]] [[Category:Hipparcos objects|100017]]