{{Short description|Star in the constellation Hydra}} {{hatnote|For other stars with this [[Bayer designation]], see [[Chi Hydrae|χ Hydrae]]}} {{DISPLAYTITLE:Chi<sup>1</sup> Hydrae}} {{Starbox begin | name = Chi<sup>1</sup> Hydrae }} {{Starbox image | image = {{Location mark |image=Crater constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=Chi1 Hydrae |x=665|y=930 }} | caption = Location of χ<sup>1</sup> Hydrae (circled in red) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Hydra (constellation)|Hydra]]<ref name=constellation/> | ra = {{RA|11|05|19.90766}}<ref name=vanLeeuwen2007/> | dec = {{DEC|-27|17|36.9957}}<ref name=vanLeeuwen2007/> | appmag_v = 4.94<ref name=Johnson1966/> }} {{Starbox character | class = {{nowrap|F4 V + F7 V}}<ref name=Eggleton2008/> | b-v = +0.36<ref name=Johnson1966/> | u-b = +0.04<ref name=Johnson1966/> | r-i = | variable = }} {{Starbox astrometry | radial_v = {{Val|+19.1|1.6}}<ref name=deBruijne2012/> | prop_mo_ra = −190.728<ref name=dr2/> | prop_mo_dec = −6.273<ref name=dr2/> | parallax = 22.8323 | p_error = 0.1828 | parallax_footnote = <ref name=dr2/> | absmag_v = 1.74<ref name=Nordstroem2004/> }} {{Starbox orbit | reference = <ref name=Mason1999/> | period = {{Val|7.5535|0.0064}} | axis = {{Val|0.1388|0.0016}} | eccentricity = {{Val|0.349|0.015}} | inclination = {{Val|96.50|0.84}} | node = {{Val|224.00|0.59}} | periastron = {{nowrap|1983.455 ± 0.084}} | periarg = {{Val|343.0|4.3}} }} {{Starbox detail | source = | component1 = χ<sup>1</sup> Hya A | mass = 1.93<ref name=Jaime2012/> | radius = 3.19<ref name=dr2/> | luminosity = 17.798<ref name=dr2/> | temperature = 6,637<ref name=dr2/> | gravity = | metal_fe = −0.10<ref name=Nordstroem2004/> | rotational_velocity = | age_gyr = 1.3<ref name=Nordstroem2004/> | component2 = χ<sup>1</sup> Hya B | mass2 = 1.93<ref name=Jaime2012/> }} {{Starbox catalog | names = [[Bayer designation|χ<sup>1</sup> Hya]], [[Durchmusterung|CD]]−26°8338, [[FK5]] 419, [[Gliese Catalogue of Nearby Stars|GJ]] 3642, [[Henry Draper Catalogue|HD]] 96202, [[Hipparcos Catalogue|HIP]] 54204, [[Harvard Revised catalogue|HR]] 4314, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]] 179514<ref name=SIMBAD/> }} {{Starbox reference | Simbad = chi01+Hya }} {{Starbox end}} '''Chi<sup>1</sup> Hydrae''' ('''χ<sup>1</sup> Hydrae''') is a [[binary star]]<ref name=Eggleton2008/> in the equatorial [[constellation]] of [[Hydra (constellation)|Hydra]]. It originally received the [[Flamsteed designation]] of '''9 Crateris''' before being placed in the Hydra constellation.<ref name=Wagman1987/> Based upon an annual [[stellar parallax|parallax shift]] of 22.8 [[milliarcsecond|mas]] as seen from Earth, it is located about 143 [[light year]]s from the [[Sun]]. It is visible to the naked eye with a combined [[apparent visual magnitude]] of 4.94.<ref name=Johnson1966/>
The two components of this system appear to have equal masses of 1.93 times the [[solar mass|mass of the Sun]].<ref name=Mason1999/> The pair circle each other with an [[orbital period]] of 7.55 years with an [[orbital eccentricity|eccentricity]] of 0.35.<ref name=Mason1999/>
==References== <references> <ref name=constellation>{{cite constellation|9 Crt|mode=cs2|postscript=.}}</ref>
<ref name=vanLeeuwen2007>{{citation | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}</ref>
<ref name=Johnson1966>{{citation | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | display-authors=1 | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | year=1966 | page=99 | bibcode=1966CoLPL...4...99J | postscript=. }}</ref>
<ref name=Nordstroem2004>{{citation | title=The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs | display-authors=1 | last1=Nordström | first1=B. | last2=Mayor | first2=M. | last3=Andersen | first3=J. | last4=Holmberg | first4=J. | last5=Pont | first5=F. | last6=Jørgensen | first6=B. R. | last7=Olsen | first7=E. H. | last8=Udry | first8=S. | last9=Mowlavi | first9=N. | journal=Astronomy and Astrophysics | postscript=. | volume=418 | pages=989–1019 | date=May 2004 | doi=10.1051/0004-6361:20035959 | bibcode=2004A&A...418..989N | arxiv=astro-ph/0405198 | s2cid=11027621 }}</ref>
<ref name=Jaime2012>{{citation | display-authors=1 | last1=Jaime | first1=Luisa G. | last2=Pichardo | first2=Barbara | last3=Aguilar | first3=Luis | title=Regions of dynamical stability for discs and planets in binary stars of the solar neighbourhood | journal=Monthly Notices of the Royal Astronomical Society | volume=427 | issue=4 | pages=2723–2733 | date=December 2012 | bibcode=2012MNRAS.427.2723J | doi=10.1111/j.1365-2966.2012.21839.x | doi-access=free | arxiv=1208.2051 | s2cid=118570249 | postscript=. }}</ref>
<ref name=Mason1999>{{citation | title=Binary Star Orbits from Speckle Interferometry. I. Improved Orbital Elements of 22 Visual Systems | display-authors=1 | last1=Mason | first1=Brian D. | last2=Douglass | first2=Geoffrey G. | last3=Hartkopf | first3=William I. | journal=The Astronomical Journal | postscript=. | volume=117 | issue=2 | pages=1023–1036 | date=February 1999 | doi=10.1086/300748 | bibcode=1999AJ....117.1023M | doi-access=free }}</ref>
<ref name=deBruijne2012>{{citation | last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project | journal=Astronomy & Astrophysics | volume=546 | id=A61 | pages=14 | date=October 2012 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}</ref>
<ref name=Eggleton2008>{{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=389 | issue=2 | pages=869–879 | date=September 2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E | postscript=. | arxiv=0806.2878 | s2cid=14878976 }}</ref>
<ref name=Wagman1987>{{citation | last=Wagman | first=M. | postscript=. | title=Flamsteed's Missing Stars | journal=Journal for the History of Astronomy | volume=18 | page=216 |date=August 1987 | issue=3 | bibcode=1987JHA....18..209W | doi=10.1177/002182868701800305| s2cid=118445625 }}</ref>
<ref name=SIMBAD>{{cite simbad | mode=cs2 | title=chi01 Hya | accessdate=2017-03-17 | postscript=. }}</ref>
<ref name=dr2>{{cite DR2|3532314252513733888}}</ref> </references>
{{Stars of Hydra|state=collapsed}}
[[Category:F-type main-sequence stars]] [[Category:Binary stars]] [[Category:Hydra (constellation)]] [[Category:Bayer objects|Hydrae, Chi1]] [[Category:Bright Star Catalogue objects|4314]] [[Category:Henry Draper Catalogue objects|096202]] [[Category:Hipparcos objects|054204]] [[Category:Flamsteed objects|Crateris, 9]] [[Category:Durchmusterung objects|CD-26 08338]]