{{Short description|Star in the constellation Hydra}} {{lowercasetitle}} {{about-distinguish2|m Hydrae|[[Mu Hydrae|μ (Mu) Hydrae]]}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Libra constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=54 Hydrae |x=685|y=705 }} | caption = Location of 54 Hydrae (circled in red) }} {{Starbox observe | epoch = J2000 | constell = [[Hydra (constellation)|Hydra]] | ra = {{RA|14|46|00.08}}<ref name=SIMBAD>{{cite simbad |title=54 Hya | accessdate=2026-01-17 }}</ref> | dec = {{DEC|-25|26|35.44}}<ref name=SIMBAD /> | appmag_v = 4.95<ref name=skylive>https://theskylive.com/sky/stars/54-hydrae-star</ref> {{nowrap|(5.2 + 7.4)}}<ref name=dibonsmith/> }} {{Starbox character | type = [[Asymptotic Giant Branch|AGB]]+main sequence<ref name=skylive/> | class = F2III+G1V<ref name=skylive/> | b-v = +0.35<ref name=hr /> | u-b = | variable = }} {{Starbox astrometry | radial_v = {{Val|5.4|3.8}}<ref name=SIMBAD/> | prop_mo_ra = 151.50<ref name=SIMBAD /> | prop_mo_dec = 107.28<ref name=SIMBAD /> | parallax = 33.02 | p_error = 0.92 | parallax_footnote = <ref name=SIMBAD /> | absmag_v = 2.73<ref name=hr>{{cite book|title=The Bright Star Catalogue|last1=Hoffleit|first1=Dorrit|last2=Jaschek|first2=Carlos|author-link=Dorrit Hoffleit|author2-link=Carlos Jaschek|bibcode=1991bsc..book.....H|publisher=[[Yale University Observatory]]|year=1991}} [http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=5050&-corr=PK=HR&-out.max=9999&HR=2875 VizieR Detail Page]</ref> }} {{Starbox detail | source = | component1 = 54 Hya A | mass = {{Val|1.35|0.15}} | radius = 1.71 | luminosity = | temperature = 7,158 | metal_fe = | gravity = | rotational_velocity = 112.5 | rotation = | age_gyr = | component2 = 54 Hya B | mass2 = {{Val|1.3|0.1}} | radius2 = {{Val|1.2|0.1}} | luminosity2 = | temperature2= | metal_fe2 = | gravity2 = | rotational_velocity2 = | rotation2 = | age_gyr2 = }} {{Starbox catalog | names = {{odlist | B=m Hya | F=54 Hya | CD=−24°11661 | HD=129926 | HIP=72197 | HR=5497 | SAO=182855 | ADS=9375 | WDS=J14460-2527 | GJ=9494 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=m+Hya }} {{Starbox end}} '''54 Hydrae''', also known by its [[Bayer designation]] '''m Hydrae''', is a binary star 99 light-years from Earth, easily divisible in small amateur telescopes. The primary is a yellow star of magnitude 5.2 and the secondary is a purple star of magnitude 7.4. They are separated by 8.4 arcseconds.<ref name=dibonsmith>http://www.dibonsmith.com/hya_54.htm</ref>
==Nomenclature== ''54 Hydrae'' is the star’s [[Flamsteed designation]], while it also has the Bayer designation '''m Hydrae''', which was not given by [[Johann Bayer]], but by [[Benjamin Apthorp Gould]], which he included in his Uranometria Argentina.<ref>http://www.uranometriaargentina.com/</ref> It should not be confused with 42 Hydrae, which has the Bayer designation [[Mu Hydrae]]. Before Gould, it was also included in the obsolete constellation of [[Turdus Solitarius]], where it was designated Delta (δ) Turdii Solitarii.<ref name=ridpath>http://www.ianridpath.com/startales/solitaire.html Ian Ridpath's Star Tales - Turdus Solitarius]</ref>
In [[Chinese astronomy|Chinese]], {{lang|zh|折威}} ({{lang|zh-Latn|Shé Wēi}}), meaning ''[[Neck (Chinese constellation)|Executions]] (asterism)'', refers to an asterism consisting of [[Sigma Librae|σ Librae]], [[50 Hydrae]], [[3 Librae]], [[4 Librae]] and [[12 Librae]].<ref>{{in lang|zh}} ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}.</ref> It was considered as an “extra” star, and was given the [[Chinese star names|Chinese name]] {{lang|zh|折威增三}} ({{lang|zh-Latn|Shé Wēi Zēng Sān}}, {{langx|en|the Third Extra Star of Executions}}).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060628.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 28 日] {{Webarchive|url=https://web.archive.org/web/20110716122210/http://aeea.nmns.edu.tw/2006/0606/ap060628.html |date=2011-07-16 }}</ref>
==References== {{reflist}} {{Hydra (constellation)}}
[[Category:G-type main-sequence stars]] [[Category:Hydra (constellation)]] [[Category:Bayer objects|Hydrae, m]] [[Category:Durchmusterung objects|CD-24 11661]] [[Category:Flamsteed objects|Hydrae, 54]] [[Category:Henry Draper Catalogue objects|129926]] [[Category:Hipparcos objects|072197]] [[Category:Bright Star Catalogue objects|5497]] [[Category:Gliese and GJ objects|9494]]