编辑“︁EBLM J0555-57”︁

{{Starbox begin|name=EBLM J0555-57}}
{{Starbox observe
|epoch=J2000
|constell=[[繪架座]]
|ra={{	RA|05|55|32.6868}}<ref name=Gaia>{{cite journal|bibcode=2016A&A...595A...2G|doi=10.1051/0004-6361/201629512|arxiv=1609.04172|title=Gaia Data Release 1|journal=Astronomy & Astrophysics|volume=595|pages=A2|year=2016|author=Gaia Collaboration}}</ref>
|dec={{DEC|-57|17|26.064}}<ref name=Gaia/>
|appmag_v=9.98 / 10.76<ref name="ebl"/>
}}
{{Starbox character
|class=F8<ref name=wds>{{cite journal|bibcode=2001AJ....122.3466M|title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog|url=https://archive.org/details/sim_astronomical-journal_2001-12_122_6/page/3466|journal=The Astronomical Journal|volume=122|issue=6|pages=3466|author1=Mason|first1=Brian D.|last2=Wycoff|first2=Gary L.|last3=Hartkopf|first3=William I.|last4=Douglass|first4=Geoffrey G.|last5=Worley|first5=Charles E.|year=2001|doi=10.1086/323920}}</ref>
|variable=[[食雙星]]<ref name=ebl/>
}}
{{Starbox astrometry
|radial_v=23.419 ± 0.74<ref name=rave>{{cite journal|bibcode=2017AJ....153...75K|title=The Radial Velocity Experiment (RAVE): Fifth Data Release|journal=The Astronomical Journal|volume=153|issue=2|pages=75|author1=Kunder|first1=Andrea|last2=Kordopatis|first2=Georges|last3=Steinmetz|first3=Matthias|last4=Zwitter|first4=Tomaž|last5=McMillan|first5=Paul J.|last6=Casagrande|first6=Luca|last7=Enke|first7=Harry|last8=Wojno|first8=Jennifer|last9=Valentini|first9=Marica|last10=Chiappini|first10=Cristina|last11=Matijevič|first11=Gal|last12=Siviero|first12=Alessandro|last13=De Laverny|first13=Patrick|last14=Recio-Blanco|first14=Alejandra|last15=Bijaoui|first15=Albert|last16=Wyse|first16=Rosemary F. G.|last17=Binney|first17=James|last18=Grebel|first18=E. K.|last19=Helmi|first19=Amina|last20=Jofre|first20=Paula|last21=Antoja|first21=Teresa|last22=Gilmore|first22=Gerard|last23=Siebert|first23=Arnaud|last24=Famaey|first24=Benoit|last25=Bienaymé|first25=Olivier|last26=Gibson|first26=Brad K.|last27=Freeman|first27=Kenneth C.|last28=Navarro|first28=Julio F.|last29=Munari|first29=Ulisse|last30=Seabroke|first30=George|display-authors=29|year=2017|doi=10.3847/1538-3881/153/2/75}}</ref>
|prop_mo_ra=3.858<ref name=Gaia/>
|prop_mo_dec=-39.713<ref name=Gaia/>
|parallax=5.16
|p_error=0.36
|parallax_footnote=<ref name=Gaia/>
}}
{{Starbox relpos
|epoch=1998
|primary=A
|component=B
|angdistsec=2.50
|angdistref=<ref name=wds/>
|posang=254
|posangref=<ref name=wds/>
|projsep=479
|projsepref=<ref name=ebl/>
}}
{{Starbox orbit
|reference=<ref name="ebl"/>
|primary=Aa
|name=Ab
|period_unitless={{val|7.757676|+0.000029|-0.000025}} d
|axis_unitless=0.0817 ± 0.0019 au
|eccentricity={{val|0.0894|+0.0035|-0.0036}}
|inclination={{val|89.84|+0.2|-1.8}}
|periarg={{val|−53.7|+1.5|-1.8}}
}}
{{Starbox detail
|source=<ref name="ebl"/>
|component1=EBLM J0555-57A
|temperature=6461 ± 124
|gravity=4.18 ± 0.21
|metal_fe=−0.24 ± 0.16
|rotational_velocity=7.60 ± 0.28
|mass=1.13 ± 0.08
|radius={{val|0.99|+0.15|-0.03}}
|component2=EBLM J0555-57Ab
|mass_mj2={{val|85.2|+4.0|-3.9}}
|radius_rj2={{val|0.84|+0.14|-0.04}}
|gravity2={{val|5.50|+0.03|-0.13}}
}}
{{Starbox detail|no_heading=
|component1=EBLM J0555-57B
|radius=0.94 ± 0.08
|temperature=5717 ± 124
|distance from Earth=632 ±0.1. ly}}
{{Starbox catalog
|names=[[科尔多瓦巡天星表|CD]]−57 1311, [[好望角照相星表|CPD]]−57 913, [[華盛頓雙星目錄|WDS]] J05555-5717, [[依巴谷星表|TYC]] 8528-926-1, [[2微米全天巡天|2MASS]] J05553262-5717261
}}
{{Starbox reference
|Simbad=CD-57+1311
}}
{{Starbox end}}
'''EBLM J0555-57'''是一個距離地球約600光年的三合星系統。系統中的'''EBLM J0555-57Ab'''是該系統中體積最小的成員星，軌道週期7.8日，並且自發現起該恆星是已知足以讓核心中進行氫核融合反應的恆星中質量最小者。
== 恆星系統 ==
EBLM J0555-57，即CD−57 1311，,是一個位於[[繪架座]]的三合星系統<ref name="ebl">{{Cite journal |last=von Boetticher |first=Alexander |last2=Triaud |first2=Amaury H. M. J. |last3=Queloz |first3=Didier |last4=Gill |first4=Sam |last5=Lendl |first5=Monika |last6=Delrez |first6=Laetitia |last7=Anderson |first7=David R. |last8=Collier Cameron |first8=Andrew |last9=Faedi |first9=Francesca |last10=Gillon |first10=Michaël |last11=Gómez Maqueo Chew |first11=Yilen |date=2017-08 |title=The EBLM project: III. A Saturn-size low-mass star at the hydrogen-burning limit⋆ |url=http://www.aanda.org/10.1051/0004-6361/201731107 |journal=Astronomy & Astrophysics |volume=604 |arxiv=1706.08781 |bibcode=2017A&A...604L...6V |doi=10.1051/0004-6361/201731107 |issn=0004-6361}}</ref><ref>{{cite web |last=Wenz |first=John |date=2017-07-11 |title=This Is the Smallest Star Ever Discovered |url=http://www.popularmechanics.com/space/deep-space/news/a27260/smallest-star-ever-discovered-by-astronomers/ |archive-url=https://web.archive.org/web/20190428030941/https://www.popularmechanics.com/space/deep-space/news/a27260/smallest-star-ever-discovered-by-astronomers/ |archive-date=2019-04-28 |accessdate=2017-07-17 |work={{link-en|大眾機械|Popular Mechanics|Popular Mechanics}} |dead-url=no }}</ref>，其中兩顆類太陽恆星是望遠鏡可辨認的[[目視聯星]]，在天球上距離2.5"。這兩顆恆星中，EBLM J0555-57Aa是視星等9.98的[[恆星光譜|F8]]恆星，另一顆EBLM J0555-57B的視星等為10.76。目前尚未觀測到這兩顆恆星之間的軌道運動，但它們有接近相等的徑向速度，並且兩者被認為有重力交互作用<ref name="ebl" />。

系統中的EBLM J0555-57A本身是一個食聯星系統（伴星EBLM J0555-57Ab環繞主星EBLM J0555-57Aa）。天文學家在近紅外線波段觀測到[[食 (天文現象)|恆星食]]，即搜尋系外行星時觀測的[[凌 (天體)|凌星]]現象，並且現象發生時主星亮度下降0.05%。光變曲線的形狀與恆星食持續時間讓天文學家得以判定兩顆恆星的半徑。該聯星系的軌道完整解為周期7日18時，[[軌道離心率]]0.09，[[軌道傾角]]則是幾乎完全以側面面對觀測者的89.84°，軌道[[半長軸]]則是0.08天文單位<ref name="ebl" />。

== EBLM J0555-57Ab ==
EBLM J0555-57Ab的質量大約是85 ± 4 [[木星質量]]，或[[太陽質量]]的0.081307189倍。它的半徑與[[土星]]相當。EBLM J0555-57Ab的狀態位於當前恆星模型中核心可發生氫融合的天體質量下限。EBLM J0555-57Ab是由[[劍橋大學]]與EBLM計畫（低質量食聯星，Eclipsing Binary, Low Mass）的天文學家團隊<ref name="ebl" />分析[[超廣角尋找行星]]計畫的凌星觀測資料時發現<ref>{{cite news|title=Smallest-ever star discovered by astronomers|url=https://phys.org/news/2017-07-smallest-ever-star-astronomers.html|accessdate=2017-07-12|publisher=Phys.org|date=2017-07-12|archive-date=2017-07-12|archive-url=https://web.archive.org/web/20170712134228/https://phys.org/news/2017-07-smallest-ever-star-astronomers.html|dead-url=no}}</ref>。天文學家另外使用[[都卜勒光譜學]]法測定該系統恆星的其他特性，即量測主星受到半星重力影響產生的徑向速度變化<ref name="ebl" />。
{{wikinews|Astronomers discover smallest known star}}

== 參考資料 ==
{{reflist}}

== 外部連結 ==
*[https://www.cam.ac.uk/research/news/smallest-ever-star-discovered-by-astronomers Smallest ever star discovered by astronomers]{{Wayback|url=https://www.cam.ac.uk/research/news/smallest-ever-star-discovered-by-astronomers |date=20170822133628 }} University of Cambridge

{{Stars of Pictor}}

[[Category:2MASS天體|J05553262-5717261]]
[[Category:BD、CD和CP天体|CD-57 1311]]
[[Category:三星系統]]
[[Category:食雙星]]
[[Category:繪架座]]
[[Category:F型主序星]]