编辑“︁C/2014 UN271”︁

{{noteTA|G1=Astronomy}}
{{DISPLAYTITLE:{{mp|C/2014 UN|271}} (伯納迪內利–伯恩斯坦)}}
{{Infobox Comet
 | name            = {{mp|C/2014 UN|271}}<br/>（伯納迪內利–伯恩斯坦）
 | image           = 2014 UN271 Jan 2022 Hubble crop.png
 | image_size      = 250
 | caption         = 2022年1月8日由[[哈伯太空望遠鏡]]於2022年1月8日拍攝的{{mp|C/2014 UN|271}}。
 | discoverer      = {{ubl|佩德羅·伯納迪內利|[[加里·伯恩斯坦]]|([[暗能量巡天]])}}
 | discovery_date  = 2014年10月20日<br/>（發現的第一張影像）
 | designations    = {{ubl|{{mp|2014 UN|271}}|伯納迪內利–伯恩斯坦彗星<ref name="NOIRLab"/>|"BB"<ref name="Bernardinelli2021"/>}}
 | epoch           = {{ubl|{{nowrap|1600年1月1日（入境）{{efn-la|name=epoch1600|1=曆元1600年1月1日，軌道週期為"PR = 1.00E+09 / 365.25日" = 〜275萬年<ref name="horizons-ssb"/>。1600年，這顆彗星距離太陽仍有310 AU，尚未進入太陽系的行星區域<ref name="1600-2500-dist"/>}}}}|{{nowrap|2500年1月1日（出境）{{efn-la|name=epoch2500|1=曆元2500年1月1日，軌道週期為"PR = 1.63E+09 / 365.25日" =〜447萬年<ref name="horizons-ssb"/>。在2,500年，這顆彗星距離太陽328 AU，將離開太陽系的行星區域<ref name="1600-2500-dist"/>}}。}}}}
 | obs_arc         = 7.50年（2,740日）
 | obs             = 133<ref name="MPC-object"/>
 | orbit           = [[歐特雲]]
 | source          = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%271600-01-01%27&STOP_TIME=%272500-01-01%27&STEP_SIZE=%27900%20years%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%27
 | aphelion        = ≈ 39,300 AU（入境）<br/>≈ 54,300 AU（出境）
 | perihelion      = {{convert|10.9502|AU|e9km|abbr=unit|sigfig=3}}<ref name="perihelion"/>{{efn-la|name=uncertainty|The [[3-sigma]] uncertainty in the perihelion distance is ±76,000 km.<ref name="perihelion"/>}}
 | next_p          = ≈ 23 January 2031年1月23日{{efn-la|name=perihelion|[[Apsis#Time of perihelion|Perihelion passage]]: Since perihelion has not yet occurred and the orbit is highly eccentric, an [[Epoch (astronomy)|epoch]] closer to 2031 will give a more accurate estimated perihelion date that better accounts for continuing planetary [[Perturbation (astronomy)|perturbations]]. The [[JPL SBDB]]'s epoch 2016 unperturbed [[二體問題|two-body]] solution (Sun+comet) gives a date of 2031-Jan-21. But properly integrating the orbit with [[JPL Horizons]] to perihelion passage accounts for all planetary perturbations and gives a date of 2031-Jan-23.<ref name="perihelion"/>}}
 | semimajor       = ≈ 19,600 AU（入境）<br/>≈ 27,200 AU（出境）
 | eccentricity    = 0.99942（入境）<br/>0.99960（出境）
 | period          = ≈ 275萬年（入境）<br/>≈ 447萬年（入境）
 | inclination     = 95.466°（入境）<br/>95.460°（出境）
 | node            = 190.003°（入境）<br/>190.009°（出境）
 | peri            = 326.280°（入境）<br/>326.246°（出境）
 | tjup            = –0.398<ref name="jpldata" />
 | Jupiter_moid    = 6.173 AU<ref name="jpldata"/>
 | dimensions      = {{val|119|15}}{{efn-la|name=diameter|The uncertainty in {{mp|C/2014 UN|271}}'s [[Thermal radiation|thermal emission]]-derived diameter largely comes from the unknown level of thermal contamination by [[Comet dust|cometary dust]] surrounding the nucleus. The lower-limit estimate {{val|119|15|u=km}} assumes maximal dust contamination, while the upper-limit estimate {{val|137|17|u=km}} assumes negligible dust contamination.<ref name="Hui2022"/>}} to {{val|137|17|u=km}}<ref name="Lellouch2022"/>
 | albedo          = {{val|0.033|0.009}}至{{val|0.044|0.012}}{{efn-la|name=albedo|As with the case of {{mp|C/2014 UN|271}}'s thermal-derived diameter, the uncertainty in {{mp|C/2014 UN|271}}'s visual ([[Photometric system|V-band]]) [[geometric albedo]] largely comes from the unknown level of thermal contamination by [[Comet dust|cometary dust]] surrounding the nucleus. The lower-limit albedo {{val|0.033|0.009}} is calculated from the upper-limit diameter assuming negligible dust contamination, while the upper-limit albedo {{val|0.044|0.012}} is calculated from the lower-limit diameter assuming maximal dust contamination.<ref name="Hui2022"/>}}
 | M1              = {{val|6.2|0.9}}<ref name="jpldata"/>
 | M2              = {{val|8.63|0.11}}<ref name="Hui2022"/>
}}

'''{{mp|C/2014 UN|271}}（伯納迪內利–伯恩斯坦）'''，簡稱為'''{{mp|C/2014 UN|271}}'''或'''伯納迪內利–伯恩斯坦彗星'''（暱稱為'''BB'''）<ref name="Bernardinelli2021"/>，是天文學家佩德羅·貝爾納迪內利和[[加里·伯恩斯坦]]在[[暗能量巡天]]的檔案影像中發現的一顆巨大的[[歐特雲]][[彗星]]<ref name="MPEC-2021-M53"/><ref name="NOIRLab"/>。在2014年10月首次發現其影像時，該物體與太陽的距離為{{convert|29|AU|e9km e9mi|sigfig=2|abbr=unit|lk=in}}，幾乎與[[海王星]]的軌道一樣遠，並且是發現時距離太陽最遠的一顆彗星<ref name="noirlab2119a"/>。它的[[彗核|核]]直徑至少為{{cvt|120|km|mi}}，是已知最大的歐特雲彗星。它正在接近太陽，並將在2031年1月到達其[[近日點]]，屆時距離為10.9AU（仍在[[土星]]軌道之外）<ref name="jpldata"/>。因為它不會進入[[太陽系#內太陽系|內太陽系]]，因此肉眼依然看不見它{{efn-la|name=brightness|Even though they have a large nucleus, comets such as {{mp|C/2014 UN|271}} (137&nbsp;km) at 11 AU, [[95P/Chiron]] (215&nbsp;km) at 8 AU, and [[C/2002 VQ94 (LINEAR)|{{mp|C/2002 VQ|94}}]] (96&nbsp;km) at 7 AU do not become visible to the naked eye because they stay outside of the [[inner Solar System]]. Comet [[Hale-Bopp]] (74&nbsp;km) was visible to the naked eye as it passed within 1 AU of the Sun.}}。

== 觀測史 ==
=== 發現 ===
[[File:Comet Bernardinelli-Bernstein annotated - noirlab2119b.jpg|缩略图|左|[[暗能量巡天]]於2017年10月拍攝的{{mp|C/2014 UN|271}}的彩色複合圖像。]]
{{mp|C/2014 UN|271}}是天文學家佩德羅·伯納迪內利（Pedro Bernardinelli）和加里·伯恩斯坦（Gary Bernstein）在[[算法|演算法]]協助搜索緩慢移動的[[海王星外天體]]時，從[[托洛洛山美洲際天文台]][[暗能量巡天]]（DES）的檔案圖像中發現的<ref name="Bernardinelli2022"/>。它在2014年10月10日至2018年11月26日的42張DES影像中，檢測到當時[[視星等]]僅有22等的彗星<ref name="Bernardinelli2021"/>。DES影像的長[[觀測弧]]顯示，儘管該天體在影像中看起來像小行星（點狀），但該天體是以近似[[抛物線軌道]]朝向太陽接近中，這意味著它起源於[[歐特雲]]<ref name="Bernardinelli2021"/><ref name="physicsworld"/>。在DES首次檢出的影像中，該物體位於[[南天 (天球)|南天]][[星座]][[玉夫座]]，與太陽的距離為{{ convert | 29.0 | AU | e9km e9mi | abbr=unit sigfig 2}}，已在[[海王星]]的軌道內側<ref name="2010-2023"/><ref name="NOIRLab"/>。從它的距離來看，該物體相對較高的亮度表明其直徑必須在{{cvt|100|km|mi}}的數量級上，對來自彗星起源地的物體來說，這是一個非常大的尺寸<ref name="Bernardinelli2021"/>。

這一發現於2021年6月19日由[[小行星中心]]宣佈，該天體的[[天文學臨時編號|臨時名稱]]是[[小行星]] {{mp | 2014 UN | 271}}<ref name="MPEC-2021-M53"/>{{efn-la|name=provisional|The [[Provisional designation in astronomy#New-style provisional designation|provisional designation]] of a minor planet indicates its discovery date and order.<ref name="MPC-DesDoc"/>}}。對於{{mp|2014 UN|271}}這名稱，2014年是拍攝第一張發現影像的時間，U是發現的那半個月（10月下旬），N271是該半月發現的第6788顆（N271=271*25+13）。該天體引起了全世界天文學家的極大關注：天文學家進行了後續觀測，並在宣佈后的幾天內發現了幾個[[回溯發現]]<ref name="MPEC-2021-M83"/>。回溯發現最早的{{mp | 2014 UN | 271}}觀測結果是來自[[帕瑞納天文台|帕拉納天文台]]的[[可見光和紅外巡天望遠鏡]]於2010年11月15日拍攝的影像，當時該天體距離太陽{{convert | 34.1 | AU | e9km e9mi | abbr=unit sigfig 2}}<ref name="Bernardinelli2021"/>。

=== 彗星活動 ===
2021年6月22日， {{link-en|拉斯坎布雷斯天文台|Las Cumbres Observatory]}}的天文學家{{link-en|Tim Lister|Tim Lister (astronomer)}}，使用南非天文台位在南非薩瑟蘭附近的觀測站，由盧卡·布茲設在納米比亞的遠程望遠鏡SkyGems，首次報導了{{mp | 2014 UN | 271}}的彗星活動。觀測結果發現這顆彗星比預測的要亮一個[[視星等|星等]]，稍不對稱的[[彗髮]]寬度高達15[[弧秒]]<ref name="ATel14733"/><ref name="MPEC-2021-M83"/>。當時，彗星與太陽的距離為{{convert | 20.2 | AU | e9km e9mi | abbr=unit sigfig=2}}<ref name="ATel14733"/>。2021年6月24日，小行星中心證實了彗星活動的觀測，彗星正式[[彗星的命名]]為{{mp|C/2014 UN|271}}（Bernardinelli–Bernstein）<ref name="MPEC-2021-M83"/>{{efn-la|name=designation|在官方的[[彗星的命名]]中，前綴的"C /"表示非週期性軌道，附加的姓氏稱許彗星的發現者。<ref name="IAU-naming"/>}}。

對[[NASA]]的[[凌日系外行星巡天衛星]]（Transiting Exoplanet Survey Satellite，TESS）存檔影像的分析表明，早在2018年9月，在距離太陽{{convert | 23.8 | AU | e9km | abbr=unit sigfig=2}}的觀測中，{{mp|C/2014 UN|271}}就有一個廣闊的、彌漫的彗髮，寬度至少為43弧秒<ref name="Bernardinelli2021"/><ref name="ATel14759"/>。在2018年至2020年的TESS觀測期間，彗星的亮度顯著增加了1.5個星等，這可能是持續活動而非自發爆發的結果<ref name="Bernardinelli2021"/><ref name="Farnham2021"/>。

對其他望遠鏡數據集的重新檢查也發現了從2017年開始的DES圖像（在25.1天文單位）和[[泛星計劃]]從2019年開始的圖像（在22.6天文單位）中，都有瀰漫性和明顯不對稱的彗髮。{{mp|C/2014 UN|271}}的彗發亮度自2017年以來呈指數級增長，而彗星的整體亮度在2014-2018年保持穩定，暗示在29.0天文單位發現這顆彗星發現之前，彗星的活動可能已經開始了<ref name="Bernardinelli2021"/><ref name="ATel14759"/>。從如此大的日心距觀測到彗星活動是罕見的，迄今只有另外三顆彗星：[[海爾-波普彗星]]（27.2天文單位出境）<ref name="Kramer2014"/>，[[C/2010 U3 (Boattini)]]（25.8 AU入境）和[[C/2017 K2 (泛星彗星)]]（24.0 AU入境），曾經被觀察到在日心距離大於20天文單位處表現出活動<ref name="Bernardinelli2021"/><ref name="Farnham2021"/>。{{Asof|2022}}，{{mp|C/2014 UN|271}} 保持著太陽系中發現彗星的最大距離的記錄<ref name="noirlab2119a"/>。

[[哈伯太空望遠鏡]]於2022年1月<ref name="Hui2022"/>和2022年3月<ref name="HST16878"/>觀測到{{mp | C/2014 UN | 271}}。

==== 2021爆發 ====
據9月14日報導，拉斯坎布雷斯天文臺在2021年9月9日，檢測到{{mp | C/2014 UN | 271}}的明顯爆發。與當天早些時候拍攝的影像相比，它變亮了0.65星等，達到了18.9等。基於這種增亮的計算表明{{convert | 10 to 100 | e6kg | e3ST | abbr=unit}}的灰塵在爆發期間被噴出<ref name="Marcin2022"/>。當時，這顆彗星與太陽的距離是{{convert|19.9|AU|e9km e9mi|abbr=unit sigfig=2}}<ref name="ATel14917"/>。到2021年12月，這顆彗星的亮度已經下降到19等<ref name="MPC-object"/>。

=== 掩星 ===
通過對{{mp|C/2014 UN | 271}}軌道和[[星曆]]的精確計算，發現2021-2025年間彗星幾乎沒有潜在的[[掩星]]事件，在此期間，彗星只會經過一顆明亮的恒星前面，並短暫遮擋恒星的光線<ref name="iota-85795610"/>。觀測這些掩星事件將有機會精確量測彗星的大小和位置，並蒐索周圍的塵埃和可能的衛星<ref name="Barry-wsaag"/>。2021年9月19日，澳大利亞和紐西蘭首次嘗試觀測其中一次掩星，但由於天氣條件惡劣而失敗<ref name="iota-85795610"/>。

== 可見性 ==
[[File:Comet-C2014-UN271-skypath.png|thumb|upright=2|從地球上看{{mp| C/2014 UN|271}}在天空上的路徑。這顆彗星目前正在南半球移動，將於2032年穿過[[天球赤道]]（黃色垂直線）。彗星路徑中的{{link-en|視運行環| Apparent retrograde motion}}是由地球圍繞太陽的周年運動引起的。]]
目前，{{mp|C/2014 UN|271}}的位置在[[天球赤道]]南方的赤緯{{val|-47|u=deg}}，很適合在南半球進行觀測。即將於2023年開始運作的[[薇拉·魯賓天文台]]將監測其彗星活動的演變<ref name="NOIRLab"/><ref name="physicsworld"/><ref name="spacecom"/>。因為彗星不會進入[[太陽系#內太陽系|內太陽系]]，因此這顆彗星不會變得更加活躍。預計彗星一旦到達近日點，不會比[[冥王星]]（視星等13–16）更亮，而且可能只會達到冥王星衛星[[冥衛一]]（視星等16.8）的亮度<ref name="Yoshida"/><ref name="atlasarticle"/><ref name="magnitude"/>。即使它達到冥王星的視星等，也需要大約一架{{val | 200 | u=mm}}望遠鏡才能看到<ref name="Pluto"/>。

== 彗核性質 ==
=== 大小和質量 ===
[[File:Largest comets size comparison.png|thumb|upright=2|已知最大彗星的大小和顏色比較，包括[[矮行星]][[冥王星]]和[[天然衛星|衛星]][[土衛一|米瑪斯]]、[[火衛一|佛波斯]]的尺度。{{mp|C/2014 UN|271}}是已知的第二大彗星，僅次於[[95P/開朗]]。]]

2021年，通過[[阿塔卡瑪大型毫米及次毫米波陣列]]（ALMA）進行的[[無線電波]]和[[熱輻射]]的量測估計{{mp | C/2014 UN | 271}}[[彗核]]的最大直徑為| 137±17公里（85±11英里）（假設看不見的塵埃、彗髮對彗核的熱輻射污染可以忽略不計。）<ref name="Lellouch2022"/>。ALMA的量測沒有排除塵埃與彗髮污染彗核熱輻射高達24%的可能性，因此實際直徑很可能更小<ref name="Hui2022"/>。在2022年，在設定塵埃與彗髮對彗核污染的最大值下，[[哈伯太空望遠鏡]]對{{mp | C/2014 UN | 271}}的觀測證實其最大尺寸下限為119±15公里（74±9英里）。

即使在估計的最小直徑下，{{mp|C/2014 UN|271}}也是發現的最大歐特雲彗星，比直徑小於{{cvt | 2 | km | mi}}的典型彗星大50多倍。之前已知的最大[[彗星#長週期|長週期彗星]]是{{link-en|C/2002 VQ94 (LINEAR)}}，直徑為{{cvt | 96 | km |mi}}<ref name="Korsun2014"/>，其次是[[海爾-波普彗星]]，直徑為 {{cvt|74|km|mi}}<ref name="Lellouch2022"/><ref name="spacecom"/>{{efn| [[1729年大彗星]]（C/1729 P1）也是一顆直徑可能高達{{cvt | 100 | km | mi}}的大型彗星，但這一估計非常不確定<ref name="S&T"/>。}}。唯一已知大於{{mp|C/2014 UN|271}}的彗星是[[活躍小行星|活躍]]的[[半人馬小行星]][[95P/開朗]]，其直徑約為{{cvt|215|km|mi}}<ref name="Lellouch2022"/>。

媒體稱{{mp|C/2014 UN|271}} 一顆「巨型彗星」<ref name="spacecom"/><ref name="gizmodo"/>，有些人甚至聲稱它可能是一顆[[矮行星]]<ref name="atlasarticle"/><ref name="earthsky"/><ref name="universetoday"/>。 然而，{{mp|C/2014 UN | 271}}遠遠低於[[流體靜力平衡]]的{{cvt | 400–1000 | km | mi}}直徑閾值；因此它的質量不足以通過自身引力變成球形，所以它不可能是矮行星<ref name="Grundy2019"/><ref name="scientificamerican"/>。此外，以{{mp|C/2014 UN|271}}彗核的大小，具有{{val|1|u=g/cm3}}以下的低密度；表明與矮行星的固體和[[行星分化|分化]]的內部相比，其結構具有高度多孔性<ref name="Grundy2019"/>。 

{{mp|C/2014 UN|271}}的質量和密度雖然尚未測量<ref name="Bernardinelli2021"/>，NASA粗略估計其質量為{{convert|500|e12ST|e15kg|abbr=unit|order=flip}}，大約是典型彗星的10萬倍<ref name="NASA2022"/>。

=== 反照率和顏色 ===
[[File:Illustration of Comet Bernardinelli-Bernstein.jpg|thumb|藝術家對伯納迪內利–伯恩斯坦彗星的想象。]]

根據其距離和視星等計算得出，沒有彗髮的{{mp|C/2014 UN|271}}彗核，在視覺（[[測光系統|V波段]]）上的[[絕對星等#太陽系天體的绝对星等H|絕對星等]]為{{val|8.63|0.11}}<ref name="Hui2022"/>。以給定最小的估計直徑（119公里）和絕對星等，計算出彗核具有非常低的視覺[[幾何反照率]]，上限值為{{val|4.4|1.2|u=%}}，這意味著它僅反射{{val|4.4|1.2|u=%}}的可見光，使其表面比[[煤]]更暗<ref name="NASA2022"/>。對於最大估計直徑（137公里），彗核的最小反照率為{{val|3.3|0.9|u=%}}<ref name="Hui2022"/>。{{mp|C/2014 UN|271}}的低反照率也是短週期和長週期群體的小彗星核的特徵，表明太陽系彗星的反照率、核大小和軌道類型之間缺乏相關性<ref name="Lellouch2022"/>。彗星核的低反照率通常歸因於[[宇宙線]][[離解|解離]]分子在核表面產生的[[碳]]、[[有機化合物]]和[[硫化物]]的沉積<ref name="Lellouch2022"/><ref name="NYT"/>。

對{{mp|C/2014 UN|271}}在其進入太陽系路徑中進行的光學觀測表明，其核對較長的波長似乎更具反射性，表明其呈中等紅色（儘管紅色略低於），與大多數長週期彗星相似<ref name="Bernardinelli2021"/><ref name="Lellouch2022"/>。由於彗星活動，預計{{mp|C/2014 UN|271}}彗核的反照率和顏色會隨著時間的推移而改變，特別是在通過近日點後溫度降低時；它的核質量足够大，可以在引力作用下將[[凝華]]的冰冷噴射物重新捕獲到其表面，這會與海爾-波普彗星通過近日點後觀察到的情况類似<ref name="Lellouch2022"/>。

=== 自轉 ===
因為它的亮度沒有顯示出任何顯著是因為自轉而變化的[[自轉週期|週期]]，因此{{mp|C/2014 UN|271}}的自轉週期仍是未知的。TESS在2018年和2020年進行的連續觀測沒有發現{{mp|C/2014 UN|271}}的[[光變曲線]]有週期性變化的迹象，為彗核的[[振幅]]變化設定了0.3星等的上限<ref name="Ridden-Harper2021"/><ref name="Farnham2021"/>。對2018年及之前的地面望遠鏡數據集的分析顯示，{{mp|C/2014 UN|271}}核的絕對星等有0.2等的明顯變化，但由於數據稀疏，不能確定出任何的週期性。其它因素，如小規模的塵埃爆發，尚未被排除，也可能有助於這種絕對星等的變化，這意味著核的真正自轉變化甚至可能小於0.2星等<ref name="Bernardinelli2021"/>。反之，如果這種變化完全是由彗核的自轉引起的，那麼彗核必須是近似球形的，或者旋轉軸的指向是朝著地球<ref name="Bernardinelli2021"/><ref name="Farnham2021"/>。

== 彗星屬性 ==
{{mp|C/2014 UN|271}}的彗髮在20–25AU時指數型的增亮，與來自彗核表面冰凍的[[二氧化碳]]（CO<sub>2</sub>）或[[氨]]（NH<sub>3</sub>）[[昇華]]產生的指數增亮一致<ref name="Bernardinelli2021"/>。較不豐富的[[揮發成分]]物質，如[[一氧化碳]]（CO）可能存在於{{mp|C/2014 UN | 271}}中，並可能對其遠距離活動起到額外作用，但它們的排放仍有待檢測<ref name="Bernardinelli2021"/>。 2020年11月，[[廣域紅外線巡天探測衛星#近地天体观测（NEOWISE）| NEOWISE]]以紅外線觀測，沒有檢測到來自在{{mp|C/2014 UN|271}}釋出的CO氣體；但在相同的日心距離下，20.9天文單位， CO[[釋氣|排放速率]]的上限約為海爾-波普彗星的10倍<ref name="Farnham2021"/>。

對2018-2020年TESS影像中{{mp|C/2014 UN|271}}彗髮形狀的分析表明，彗髮由次毫米級[[彗星塵|塵埃顆粒]]組成，以範圍在{{cvt|10|m/s|ft/s}}的低速噴射在附近，這表明彗星在2018年前2至10年間變得活躍<ref name="Farnham2021"/><ref name="Hui2022"/>。根據2022年1月哈伯觀測到的彗髮亮度，在20天文單位的{{mp|C/2014 UN|271}}正在以大約1,000 kg/s（1.1 short ton/s）的速度損失質量；與海爾-波普彗星在這個距離上的相似<ref name="Hui2022"/>。

== 軌道和起源 ==
[[File:2014 UN271.jpg|thumb| {{mp |C/2014 UN | 271}}以近抛物線軌道垂直穿過外太陽系的軌跡圖。]]

{{mp|C/2014 UN|271}}來自歐特雲，自2014年3月以來一直在海王星（29.9AU）軌道內，並將於2022年9月進入[[天王星]]（18.3AU）軌道內{{efn-la|name=in-out|這些行星的軌道是偏心的，所以行星軌道內的日心距離小於其近日點，而行星軌道外的日心距離大於其遠日點。}}<ref name="2010-2023"/><ref name="planetaryfactsheet"/>。[[拱點#近日點時間|近日點通過時間]]自2021年6月以來一直廣為人知<ref name="perihelion"/>。目前，彗星距離太陽的[[68–95–99.7法則|3-sigma]]不確定性為±60,000公里<ref name="2010-2023"/>。

歐特雲彗星接近和遠離太陽的[[軌道週期]]，受到行星[[攝動]]導致的軌道變化永遠不會完全相同。對於歐特雲彗星來說，在行星區域內定義的軌道可能會產生誤導性的結果。因此，應該在進入行星區域之前和離開行星區域之後，分別計算接近和遠離的軌道。使用幾年來經由數十次觀測的[[觀測弧]]，{{mp|C/2014 UN|271}}的軌道是可靠的{{efn-la|name=secure|1=[https://web.archive.org/web/20210622042200/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2014UN271 JPL 1]定義在曆元"2021年7月1日"的（4年弧），得到遠日點（Q）=14,300 AU，週期=604,000年。 [https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%272021-Jul-01%27&STOP_TIME=%272100-01-01%27&STEP_SIZE=%27150%20years%27&CENTER=%27@sun%27&OUT_UNITS=%27AU-D%27 current orbit]定義在曆元"2021年7月1日"的（6年弧），也得到遠日點（AD）=14,200 AU，和週期= ~600,000年。解決方案基本上是相同的。}} ，根據[[噴氣推進實驗室線上曆書系統]]的計算，它在1,600年的進入軌道半長軸為{{convert | 20000 | AU | ly | sigfig=1 | lk=on | abbr=on}}<ref name="horizons-ssb"/>。這表示{{mp | C/2014 UN | 271}}大約於140萬年前處在歐特雲中的最遠距離（{{convert|39000|AU|ly|sigfig=1|lk=on|abbr=on}}）<ref name="horizons-ssb"/>{{efn-la|name=epoch1600}}{{efn-la|name=near-planets|然而，像{{mp|C/2014 UN|271}}這樣一顆束縛鬆散的長週期彗星，是以最早進入太陽系行星區域的那一年來定義[[曆元]]，[[噴射推進實驗室小天體資料庫]]可能會顯示一個誤導性的日心軌道解決方案，該解決方案不會顯示真實的接近或遠離太陽的軌道週期或真實的遠日點距離<ref name="jpldata"/>。當使用太陽系[[質心]]作為其參考系，在離開行星區域之前和/或之後的那個曆元計算密切軌道時，可以獲得長週期彗星正確的軌道。使用1600年（入境）和2500年（出境）的曆元將產生更有意義的結果<ref name="horizons-ssb"/>。}}。它將在2031年1月23日左右到達[[近日點]]（最接近太陽），距離{{convert|10.95|AU| e9km e9mi| abbr=unit sigfig=2}}<ref name="perihelion"/>，就在[[土星]]軌道的遠日點（10.1天文單位之外<ref name="perihelion"/><ref name="planetaryfactsheet"/>。它將於2031年4月5日最接近地球，距離在{{convert|10.1|AU| e9km e9mi | abbr=unit sigfig=2}}左右<ref name="Earth"/>。它將於2033年8月8日越過[[黃道面]]，此時它與太陽的距離遠達{{val | 12.0 | u=AU}}<ref name="ecliptic-cross"/>。它離開太陽（出境）的軌道週期將約為450萬年，遠日點距離約為{{convert | 54000 | AU | ly | sigfig=1 | abbr=on}}<ref name="horizons-ssb"/>。在歐特雲中，該物體與壽島太陽約束的引力非常鬆散，並受到[[星系潮汐]][[攝動]]的影響<ref name="Dybczynski2021"/>。

像{{mp|C/2014 UN|271}}這樣的大型長週期彗星很少被發現，這是因為一種被稱為"衰退"的現象：在圍繞太陽運行的束縛軌道上的彗星，在每一次近日點的活動中週期性地失去質量和揮發性成分，導致其大小、亮度和活動性隨著年齡的增長而逐漸减小<ref name="Vokrouhlicky2019"/><ref name="spacecom"/>。這進一步證明{{mp | C/2014 UN | 271}}是一顆動態的新彗星<ref name="Vokrouhlicky2019"/>。 

{| class="wikitable sortable" style="text-align:center; font-size:1.0em;"
|+來自外層歐特雲的彗星
! 彗星
! 以1600年曆元入境的質心軌道遠日點<br />（天文單位）
! 以2500年曆元出境的質心軌道遠日點<br />（天文單位）
|-
| [[C/1980 E1 (Bowell)]] || 74,000 || 雙曲
|-
| [[C/1999 F1 (Catalina)]] || 55,000 || 66,000
|-
| [[C/2003 A2 (Gleason)]] || 47,000 || 15,000
|-
| [[麥克諾特彗星|C/2006 P1 (McNaught)]] || 67,000 || 4,100
|-
| [[C/2010 U3 (Boattini)]] || 34,000 || 9,900
|-
| [[C/2011 L4|C/2011 L4 (PanSTARRS)]] || 68,000 || 4,500
|-
| [[艾桑彗星|Comet ISON]] || 雙曲 || 雙曲
|-
| [[C/2013 A1|C/2013 A1 (Siding Spring)]] || 52,000 || 13,000
|-
| [[C/2013 US10|{{mp|C/2013 US|10}} (Catalina)]] || 38,000 || 雙曲
|-bgcolor=#c2c2c2
| '''{{mp|C/2014 UN|271}} (Bernardinelli–Bernstein)'''<ref name="horizons-ssb"/> || '''39,000''' || '''54,000'''
|-
| [[C/2017 K2|C/2017 K2 (PanSTARRS)]] || 46,000 || 1,800
|-
| [[C/2017 T2 (PanSTARRS)]] || 74,000 || 2,900
|}

== 勘探 ==
{{Asof | 2022}}沒有對{{mp | C/2014 UN | 271}}提出任務建議，也沒有任何即將進行的任務可以針對該彗星進行探勘。[[歐洲太空總署]]即將進行的[[彗星攔截器]]任務將於2029年發射，並在地球軌道內對一顆長週期彗星進行[[逼近飛行|飛越]]，但由於{{mp|C/2014 UN|271}}的近日點距離遙遠，將無法前往<ref name="CometInterceptor"/>。

根據[[星際研究倡議協會]]在2021年的一項研究，在2022-2029年的9月至10月期間，每年都可以有一個直接飛往{{mp|C/2014 UN|271}}的低能軌道飛越任務最佳發射窗口，與地球的最大[[ΔV|速度差]]為20公里/秒。在所有情况下，當{{mp|C/2014 UN|271}}在2033年8月以距離太陽11.9AU的距離穿過黃道面時，是最理想的時間，讓太空船將能以12-14公里/秒的相對速飛越彗星<ref name="Hibberd2021"/><ref name="Davies2021"/>。或者，可以在2020-2027年和2034-2037年發射，利用木星進行[[重力助推]]和[[重力助推#奧伯特效應|奧伯思機制]]的組合，飛行到{{mp|C/2014 UN|271}}進行探測。後一個窗口內的發射可以在完成1:1地球[[軌道共振|共振軌道]]後，利用地球飛越木星，這將顯著降低地球發射時的[[特徵能量]]（Characteristic energy），並可以在黃道上方抵達目標<ref name="Hibberd2021"/>。利用內行星連續的重力助推和軌道共振，進行飛越軌道也是可能的，但2028年之前的發射日期提供了最理想的遭遇組合，即2033年晚些時候的時間抵達彗星<ref name="Hibberd2021"/>。

雖然彗星幾乎垂直於黃道的軌道使得任何從黃道直接會合的軌道都不可行，但到{{mp|C/2014 UN|271}}的[[太空交會|交會]]軌道已被考慮<ref name="Davies2021"/>。儘管如此，在彗星越過黃道後，與{{mp|C/2014 UN|271}}的交會可以在木星重力助推下進行，最佳發射日期為2030-2034年，飛行持續時間約為14-15年<ref name="Hibberd2021"/>。

== 相關條目 ==
* {{link-en|按遠日點距離排列的太陽系天體列表|List of Solar System objects by greatest aphelion}}

== 註釋 ==
{{Reflist|group=lower-alpha|refs=

{{efn|name=perihelion|[[Apsis#Time of perihelion|Perihelion passage]]: Given perihelion is still 10 years away and the orbit is highly eccentric, an [[曆元|epoch]] closer to 2031 will give a more accurate estimated perihelion date that better accounts for continuing planetary [[攝動|perturbations]]. The [[噴射推進實驗室小天體資料庫|JPL SBDB]]'s epoch 2016 unperturbed [[二體問題|two-body]] solution (Sun+comet) gives a date of 2031-Jan-21. But properly integrating the orbit with [[噴氣推進實驗室線上曆書系統|JPL Horizons]] to perihelion passage accounts for all planetary perturbations and gives a date of 2031-Jan-23.}}

{{efn|name=epoch1950|1=For epoch 1950-Jan-01 orbit period is "PR= 9.99E+08 / 365.25 days" = ~2.7 million years. In 1950 the comet was still 95 AU from the Sun and had not entered the planetary region of the Solar System.}}

{{efn|name=epoch2100|1=For epoch 2100-Jan-01 orbit period is "PR= 1.61E+09 / 365.25 days" = ~4.4 million years. In 2100 the comet will be 84 AU from the Sun and will have exited the planetary region of the Solar System.}}

}}

== 參考資料 ==
{{reflist|30em|refs=

<!-- databases/archives -->

<ref name="jpldata">{{cite web
 |type         = 2022-02-13 last obs.
 |title        = JPL Small-Body Database Browser: C/2014 UN271 (Bernardinelli–Bernstein)
 |url          = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1003787
 |publisher    = [[Jet Propulsion Laboratory]]
 |accessdate   = 14 February 2022
 |archive-date = 2022-11-18
 |archive-url  = https://web.archive.org/web/20221118233034/https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1003787
 |dead-url     = no
}}</ref>

<ref name="MPC-object">{{cite web
  |title      = C/2014 UN271 (Bernardinelli–Bernstein)
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=C%2F2014+UN271
  |publisher  = Minor Planet Center
  |accessdate = 19 June 2021}}</ref>

<ref name="Yoshida">{{cite web
 |title        = C/2014 UN271 (Bernardinelli–Bernstein)
 |url          = http://www.aerith.net/comet/catalog/2014UN271/2014UN271.html
 |first        = Seiichi
 |last         = Yoshida
 |website      = aerith.net
 |accessdate   = 12 February 2022
 |archive-date = 2022-02-14
 |archive-url  = https://web.archive.org/web/20220214234940/http://www.aerith.net/comet/catalog/2014UN271/2014UN271.html
 |dead-url     = no
}}</ref>

<ref name="HST16878">{{cite journal
 |type         = HST Proposal 16878
 |title        = Determining the coma contents of the incoming Oort Cloud comet C/2014 UN271
 |url          = https://archive.stsci.edu/proposal_search.php?mission=hst&id=16878
 |first        = Bryce
 |last         = Bolin
 |journal      = Mikulski Archive for Space Telescopes
 |publisher    = Space Telescope Science Institute
 |date         = November 2021
 |page         = 16878
 |accessdate   = 14 February 2022
 |bibcode      = 2021hst..prop16878B
 |archive-date = 2022-12-01
 |archive-url  = https://web.archive.org/web/20221201073939/https://archive.stsci.edu/proposal_search.php?mission=hst&id=16878
 |dead-url     = no
}}</ref>

<ref name="HST16886">{{cite journal
 |type         = HST Proposal 16886
 |title        = A Remarkable Inbound Long-Period Comet at Record Heliocentric Distances
 |url          = https://archive.stsci.edu/proposal_search.php?mission=hst&id=16886
 |first        = Man-To
 |last         = Hui
 |journal      = Mikulski Archive for Space Telescopes
 |publisher    = Space Telescope Science Institute
 |date         = November 2021
 |page         = 16886
 |accessdate   = 14 February 2022
 |bibcode      = 2021hst..prop16886H
 |archive-date = 2022-02-14
 |archive-url  = https://web.archive.org/web/20220214090027/https://archive.stsci.edu/proposal_search.php?mission=hst&id=16886
 |dead-url     = no
}}</ref>

<!-- fact sheets -->
<ref name="MPC-DesDoc">{{cite web
  |title      = New- And Old-Style Minor Planet Designations
  |url      = https://minorplanetcenter.net/iau/info/DesDoc.html
  |publisher      = Minor Planet Center
  |accessdate      = 20 February 2022
  |archive-date      = 2021-05-06
  |archive-url      = https://web.archive.org/web/20210506221829/https://www.minorplanetcenter.net/iau/info/DesDoc.html
  |dead-url      = no
  }}</ref>

<ref name="IAU-naming">{{cite web
  |title      = Naming of Astronomical Objects
  |url      = https://www.iau.org/public/themes/naming/
  |publisher      = International Astronomical Union
  |accessdate      = 20 February 2022
  |archive-date      = 2013-10-31
  |archive-url      = https://web.archive.org/web/20131031154417/https://www.iau.org/public/themes/naming/
  |dead-url      = no
  }}</ref>

<ref name="planetaryfactsheet">{{cite web
 |title        = Planetary Fact Sheet - Metric
 |first        = David R.
 |last         = Williams
 |url          = https://nssdc.gsfc.nasa.gov/planetary/factsheet/
 |work         = NASA Space Science Data Coordinated Archive
 |publisher    = [[NASA]]
 |date         = 27 December 2021
 |accessdate   = 20 February 2022
 |archive-date = 2019-08-26
 |archive-url  = https://web.archive.org/web/20190826054410/https://nssdc.gsfc.nasa.gov/planetary/factsheet/
 |dead-url     = no
}}</ref>

<ref name="magnitude">{{cite web
 |title        = Pluto Fact Sheet
 |first        = David R.
 |last         = Williams
 |url          = https://nssdc.gsfc.nasa.gov/planetary/factsheet/plutofact.html
 |work         = NASA Space Science Data Coordinated Archive
 |publisher    = [[NASA]]
 |date         = 23 December 2021
 |accessdate   = 20 February 2022
 |archive-date = 2019-03-11
 |archive-url  = https://web.archive.org/web/20190311225810/https://nssdc.gsfc.nasa.gov/planetary/factsheet/plutofact.html
 |dead-url     = no
}}</ref>

<ref name="Pluto">{{cite web
  |title       = See Pluto in 2015
  |url       = https://skyandtelescope.org/observing/lets-find-pluto/
  |last       = Johnson-Roehr
  |work       = [[Sky & Telescope]]
  |date       = 4 July 2021
  |accessdate       = 4 July 2021
  |archive-date       = 2022-06-27
  |archive-url       = https://web.archive.org/web/20220627112549/https://skyandtelescope.org/observing/lets-find-pluto/
  |dead-url       = no
  }}</ref>

<!-- circulars -->

<ref name="MPEC-2021-M53">{{cite journal
 |title        = MPEC 2021-M53 : 2014 UN271
 |url          = https://minorplanetcenter.net/mpec/K21/K21M53.html
 |journal      = Minor Planet Electronic Circulars
 |publisher    = Minor Planet Center
 |date         = 19 June 2021
 |accessdate   = 19 June 2021
 |bibcode      = 2021MPEC....M...53B
 |archive-date = 2022-08-20
 |archive-url  = https://web.archive.org/web/20220820030856/https://www.minorplanetcenter.net/mpec/K21/K21M53.html
 |dead-url     = no
}}</ref>

<ref name="MPEC-2021-M83">{{cite web
 |title        = MPEC 2021-M83 : COMET C/2014 UN271 (Bernardinelli–Bernstein)
 |url          = https://minorplanetcenter.net/mpec/K21/K21M83.html
 |work         = Minor Planet Electronic Circulars
 |publisher    = Minor Planet Center
 |date         = 24 June 2021
 |accessdate   = 24 June 2021
 |archive-date = 2022-08-08
 |archive-url  = https://web.archive.org/web/20220808202537/https://minorplanetcenter.net//mpec/K21/K21M83.html
 |dead-url     = no
}}</ref>

<ref name="ATel14733">{{cite journal
 |title        = Newly discovered object 2014 UN271 observed as active at 20.18 au
 |url          = https://www.astronomerstelegram.org/?read=14733
 |first1       = Rosita
 |last1        = Kokotanekova
 |first2       = Tim
 |last2        = Lister
 |first3       = Michele
 |last3        = Bannister
 |first4       = Colin
 |last4        = Snodgrass
 |first5       = Cyrielle
 |last5        = Opitom
 |first6       = Meg
 |last6        = Schwamb
 |first7       = Michael S. P.
 |last7        = Kelley
 |journal      = The Astronomer's Telegram
 |date         = 22 June 2021
 |volume       = 14733
 |page         = 1
 |accessdate   = 22 June 2021
 |bibcode      = 2021ATel14733....1K
 |archive-date = 2021-06-22
 |archive-url  = https://web.archive.org/web/20210622185025/https://www.astronomerstelegram.org/?read=14733
 |dead-url     = no
}}</ref>

<ref name="ATel14759">{{cite journal
 |title        = Comet C/2014 UN271 (Bernardinelli–Bernstein) exhibited activity at 23.8 au
 |url          = https://www.astronomerstelegram.org/?read=14759
 |first        = Tony
 |last         = Farnham
 |journal      = The Astronomer's Telegram
 |date         = 6 July 2021
 |volume       = 14759
 |page         = 1
 |accessdate   = 6 July 2021
 |bibcode      = 2021ATel14759....1F
 |archive-date = 2022-05-25
 |archive-url  = https://web.archive.org/web/20220525060344/https://www.astronomerstelegram.org/?read=14759
 |dead-url     = no
}}</ref>

<ref name="ATel14917">{{cite journal
 |title        = Apparent Outburst of Comet C/2014 UN271 (Bernardinelli–Bernstein)
 |url          = https://www.astronomerstelegram.org/?read=14917
 |first1       = Michael S. P.
 |last1        = Kelley
 |first2       = Tim
 |last2        = Lister
 |first3       = Carrie E.
 |last3        = Holt
 |journal      = The Astronomer's Telegram
 |date         = 14 September 2021
 |volume       = 14917
 |page         = 1
 |accessdate   = 15 September 2021
 |bibcode      = 2021ATel14917....1K
 |archive-date = 2022-10-01
 |archive-url  = https://web.archive.org/web/20221001113050/https://www.astronomerstelegram.org/?read=14917
 |dead-url     = no
}}</ref>

<!-- horizons ephemerides -->

<ref name="horizons-ssb">{{cite web
  |title      = JPL Horizons On-Line Ephemeris for 2014 UN271 at epoch 1600 and 2500
  |url        = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%271600-01-01%27&STOP_TIME=%272500-01-01%27&STEP_SIZE=%27900%20years%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%27
  |work       = [[JPL Horizons On-Line Ephemeris System]]
  |publisher  = [[Jet Propulsion Laboratory]]
  |accessdate = 20 February 2022}} Solution using the Solar System [[Barycenter]]. Ephemeris Type: Elements and Center: @0 (To be outside planetary region, inbound epoch 1600 and outbound epoch 2500. Aphelia/orbital periods defined while in the planetary-region are misleading for knowing the long-term inbound/outbound solutions.)</ref>

<ref name="2010-2023">{{cite web
 |type         = Range, radial velocity/range rate, Constellation, and range 3-sigma uncertainties
 |title        = Distance from Sun from 2010 to 2023 (1 month interval)
 |url          = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%272010-01-01%27&STOP_TIME=%272023-01-01%27&STEP_SIZE=%271%20month%27&QUANTITIES=%2719,29,39%27&CENTER=%27@sun%27
 |work         = JPL Horizons On-Line Ephemeris System
 |publisher    = Jet Propulsion Laboratory
 |accessdate   = 20 February 2022
 |archive-date = 2022-11-20
 |archive-url  = https://web.archive.org/web/20221120210202/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%272010-01-01%27&STOP_TIME=%272023-01-01%27&STEP_SIZE=%271%20month%27&QUANTITIES=%2719%2C29%2C39%27&CENTER=%27%40sun%27
 |dead-url     = no
}}</ref>

<ref name="1600-2500-dist">{{cite web
  |type       = Range, radial velocity/range rate, and range 3-sigma uncertainties
  |title      = Distance from Sun in 1600 and 2500
  |url        = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%271600-01-01%27&STOP_TIME=%272500-01-01%27&STEP_SIZE=%27900%20years%27&QUANTITIES=%2719,39%27&CENTER=%27@sun%27
  |work       = JPL Horizons On-Line Ephemeris System
  |publisher  = Jet Propulsion Laboratory
  |accessdate = 20 February 2022}}</ref>

<ref name="perihelion">{{cite web
  |type       = Perihelion occurs when rdot flips from negative to positive at 00:32 UT
  |title      = Perihelion in January 2031 (1 minute interval)
  |url        = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%272031-01-23%27&STOP_TIME=%272031-01-24%27&STEP_SIZE=%2701%20minutes%27&QUANTITIES=%2719,39%27
  |work       = JPL Horizons On-Line Ephemeris System
  |publisher  = Jet Propulsion Laboratory
  |archive-url = https://web.archive.org/web/20220220041541/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%272031-01-23%27&STOP_TIME=%272031-01-24%27&STEP_SIZE=%2701+minutes%27&QUANTITIES=%2719%27
  |archive-date = 20 February 2022
  |url-status = live
  |accessdate = 20 February 2022}}</ref>

<ref name="Earth">{{cite web
 |type         = Closest Earth approach occurs when deldot flips from negative to positive
 |title        = Closest Approach to Earth in 2031 (3 hour interval)
 |url          = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%272031-03-15%27&STOP_TIME=%272031-04-15%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2720%27
 |work         = JPL Horizons On-Line Ephemeris System
 |publisher    = Jet Propulsion Laboratory
 |accessdate   = 25 June 2021
 |archive-date = 2021-07-06
 |archive-url  = https://web.archive.org/web/20210706231210/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&START_TIME=%272031-03-15%27&STOP_TIME=%272031-04-15%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2720%27
 |dead-url     = no
}}</ref>

<ref name="ecliptic-cross">{{cite web
  |type       = Ecliptic crossing occurs when Z flips from negative to positive
  |title      = Ecliptic crossing in August 2033 (1 hour interval)
  |url        = https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272014+UN271%27&TABLE_TYPE=%27VECTORS%27&START_TIME=%272033-08-08%27&STOP_TIME=%272033-08-09%27&STEP_SIZE=%271%20hours%27%20&QUANTITIES=%271%27&OUT_UNITS=%27AU-D%27&CENTER=%27@sun%27
  |work       = JPL Horizons On-Line Ephemeris System
  |publisher  = Jet Propulsion Laboratory
  |accessdate = 20 February 2022}}</ref>

<!-- news articles -->

<ref name="atlasarticle">{{cite news
 |title        = Extremely eccentric minor planet to visit inner solar system this decade
 |url          = https://newatlas.com/space/2014-un271-comet-solar-system-close-pass/
 |first        = Michael
 |last         = Irving
 |work         = New Atlas
 |date         = 20 June 2021
 |accessdate   = 21 June 2021
 |archive-date = 2022-11-26
 |archive-url  = https://web.archive.org/web/20221126201311/https://newatlas.com/space/2014-un271-comet-solar-system-close-pass/
 |dead-url     = no
}}</ref>

<ref name="S&T">{{cite news
 |title        = Giant Oort Cloud Comet Lights Up in the Outer Solar System
 |url          = https://skyandtelescope.org/astronomy-news/giant-oort-cloud-comet-lights-up-in-the-outer-solar-system/
 |first        = Jeff
 |last         = Hecht
 |work         = Sky & Telescope
 |date         = 22 June 2021
 |accessdate   = 14 April 2022
 |archive-date = 2022-11-29
 |archive-url  = https://web.archive.org/web/20221129203428/https://skyandtelescope.org/astronomy-news/giant-oort-cloud-comet-lights-up-in-the-outer-solar-system/
 |dead-url     = no
}}</ref>

<ref name="physicsworld">{{cite news
 |title        = Huge Oort Cloud object has been spotted entering the solar system
 |url          = https://physicsworld.com/a/huge-oort-cloud-object-has-been-spotted-entering-the-solar-system/
 |first        = Will
 |last         = Gater
 |work         = PhysicsWorld
 |date         = 24 June 2021
 |accessdate   = 24 June 2021
 |archive-date = 2023-01-07
 |archive-url  = https://web.archive.org/web/20230107232632/https://physicsworld.com/a/huge-oort-cloud-object-has-been-spotted-entering-the-solar-system/
 |dead-url     = no
}}</ref>

<ref name="earthsky">{{cite news
 |title        = Mega comet inbound from Oort Cloud
 |url          = https://earthsky.org/space/2014-un271-mega-comet-discovery/
 |first        = Kelly Kizer
 |last         = Whitt
 |work         = EarthSky
 |date         = 24 June 2021
 |accessdate   = 12 February 2022
 |archive-date = 2022-12-27
 |archive-url  = https://web.archive.org/web/20221227075724/https://earthsky.org/space/2014-un271-mega-comet-discovery/
 |dead-url     = no
}}</ref>

<ref name="universetoday">{{cite news
 |title        = A Newly-Discovered (Almost) Dwarf Planet Will Come Surprisingly Close in 2031
 |url          = https://www.universetoday.com/151624/a-newly-discovered-almost-dwarf-planet-will-come-surprisingly-close-in-2031/
 |first        = Andy
 |last         = Tomaswick
 |work         = Universe Today
 |date         = 24 June 2021
 |accessdate   = 12 February 2022
 |archive-date = 2022-10-03
 |archive-url  = https://web.archive.org/web/20221003171914/https://www.universetoday.com/151624/a-newly-discovered-almost-dwarf-planet-will-come-surprisingly-close-in-2031/
 |dead-url     = no
}}</ref>

<ref name="NOIRLab">{{cite news
 |title        = Giant Comet Found in Outer Solar System by Dark Energy Survey
 |url          = https://noirlab.edu/public/news/noirlab2119/
 |first        = Amanda
 |last         = Kocz
 |publisher    = NOIRLab
 |date         = 25 June 2021
 |accessdate   = 25 June 2021
 |archive-date = 2021-07-10
 |archive-url  = https://web.archive.org/web/20210710153504/https://noirlab.edu/public/news/noirlab2119/
 |dead-url     = no
}}</ref>

<ref name="noirlab2119a">{{cite web
 |title        = Illustration of Comet Bernardinelli–Bernstein
 |url          = https://noirlab.edu/public/images/noirlab2119a/
 |publisher    = NOIRLab
 |date         = 25 June 2021
 |accessdate   = 14 July 2021
 |archive-date = 2023-01-06
 |archive-url  = https://web.archive.org/web/20230106124907/https://noirlab.edu/public/images/noirlab2119a/
 |dead-url     = no
}}</ref>

<ref name="scientificamerican">{{cite news
 |title        = Astronomers Thrill at Giant Comet Flying into Our Solar System
 |url          = https://www.scientificamerican.com/article/astronomers-thrill-at-giant-comet-flying-into-our-solar-system/
 |first        = Jonathan
 |last         = O'Callaghan
 |work         = Scientific American
 |date         = 30 June 2021
 |accessdate   = 12 February 2022
 |archive-date = 2022-12-27
 |archive-url  = https://web.archive.org/web/20221227105937/https://www.scientificamerican.com/article/astronomers-thrill-at-giant-comet-flying-into-our-solar-system/
 |dead-url     = no
}}</ref>

<ref name="spacecom">{{cite web
 |title        = The 'megacomet' Bernardinelli–Bernstein is the find of a decade. Here's the discovery explained.
 |url          = https://www.space.com/giant-comet-bernardinelli-bernstein-discovery-size-activity
 |first        = Bartels
 |last         = Meghan
 |website      = Space.com
 |date         = 7 September 2021
 |accessdate   = 15 February 2022
 |archive-date = 2022-12-06
 |archive-url  = https://web.archive.org/web/20221206074005/https://www.space.com/giant-comet-bernardinelli-bernstein-discovery-size-activity
 |dead-url     = no
}}</ref>

<ref name="gizmodo">{{cite news
 |title        = Mega Comet Arriving From the Oort Cloud Is 85 Miles Wide
 |url          = https://gizmodo.com/bernardinelli-bernstein-biggest-comet-ever-1848502226
 |first        = George
 |last         = Dvorsky
 |work         = Gizmodo
 |date         = 8 February 2021
 |accessdate   = 12 February 2022
 |archive-date = 2023-01-17
 |archive-url  = https://web.archive.org/web/20230117045253/https://gizmodo.com/bernardinelli-bernstein-biggest-comet-ever-1848502226
 |dead-url     = no
}}</ref>

<ref name="Barry-wsaag">{{cite web
 |title        = Occultation by the Big Comet C/2014 UN271 from the Oort Cloud predicted for Sun 19th September at 2:45am AEST Sydney time.
 |url          = https://wsaag.org/images/events/2021-09-19_Predicted_Occultation_by_2014_UN271.pdf
 |first        = Tony
 |last         = Barry
 |publisher    = Western Sydney Amateur Astronomy Group
 |date         = 8 February 2021
 |accessdate   = 13 February 2022
 |archive-date = 2022-03-15
 |archive-url  = https://web.archive.org/web/20220315002125/https://wsaag.org/images/events/2021-09-19_Predicted_Occultation_by_2014_UN271.pdf
 |dead-url     = no
}}</ref>

<ref name="NASA2022">{{cite news
 |title        = Hubble Confirms Largest Comet Nucleus Ever Seen
 |url          = https://www.nasa.gov/feature/goddard/2022/hubble-confirms-largest-comet-nucleus-ever-seen
 |first        = Andrea
 |last         = Gianopoulos
 |work         = NASA
 |date         = 12 April 2022
 |accessdate   = 12 April 2022
 |archive-date = 2022-04-14
 |archive-url  = https://web.archive.org/web/20220414102506/https://www.nasa.gov/feature/goddard/2022/hubble-confirms-largest-comet-nucleus-ever-seen/
 |dead-url     = no
}}</ref>

<ref name="NYT">{{cite news
 |title        = Hubble Telescope Zooms In on the Biggest Comet Ever Spotted
 |url          = https://www.nytimes.com/2022/04/14/science/biggest-comet-hubble.html
 |first        = Robin George
 |last         = Andrews
 |work         = The New York Times
 |date         = 14 April 2022
 |accessdate   = 14 April 2022
 |archive-date = 2022-11-17
 |archive-url  = https://web.archive.org/web/20221117000852/https://www.nytimes.com/2022/04/14/science/biggest-comet-hubble.html
 |dead-url     = no
}}</ref>

<!-- blog/forum -->

<ref name="CometInterceptor">{{cite tweet
  |title      = There's understandably a _lot_ of excitement about the newly-discovered, apparently huge comet, 2014 UN271. Many people are asking whether our mission could reach it. After all, encountering a long-period comet is Comet Interceptor's main aim. Unfortunately,...
  |user       = CometIntercept
  |number     = 1407761815220674571
  |date       = 23 June 2021
  |accessdate = 12 February 2022}}</ref>

<ref name="iota-85795610">{{cite web
 |title        = C/2014 UN271 a bust
 |url          = https://groups.io/g/IOTAoccultations/topic/85795610
 |first        = Marshall
 |last         = Eubanks
 |work         = International Occultation Timing Association Group
 |date         = 22 September 2021
 |accessdate   = 13 February 2022
 |archive-date = 2022-02-13
 |archive-url  = https://web.archive.org/web/20220213090951/https://groups.io/g/IOTAoccultations/topic/85795610
 |dead-url     = no
}}</ref>

<!-- journal publications -->

<ref name="Korsun2014">{{cite journal |first1 = Pavlo P. |last1 = Korsun |first2 = Philippe |last2 = Rousselot |first3 = Irina V. |last3 = Kulyk |first4 = Viktor L. |last4 = Afanasiev |first5 = Oleksandra V. |last5 = Ivanova |title = Distant activity of Comet C/2002 VQ94 (LINEAR): Optical spectrophotometric monitoring between 8.4 and 16.8 au from the Sun |url = https://arxiv.org/ftp/arxiv/papers/1401/1401.3137.pdf |journal = Icarus |date = April 2014 |volume = 232 |pages = 88–96 |doi = 10.1016/j.icarus.2014.01.006 |arxiv = 1401.3137 |bibcode = 2014Icar..232...88K |s2cid = 118462955 |access-date = 2022-05-16 |archive-date = 2022-11-05 |archive-url = https://web.archive.org/web/20221105090628/https://arxiv.org/ftp/arxiv/papers/1401/1401.3137.pdf |dead-url = no }}</ref>

<ref name="Kramer2014">{{cite journal
 |first1       = Emily A.
 |last1        = Kramer
 |first2       = Yanga R.
 |last2        = Fernandez
 |first3       = Carey M.
 |last3        = Lisse
 |first4       = Michael S. P.
 |last4        = Kelley
 |first5       = Laura M.
 |last5        = Woodney
 |title        = A dynamical analysis of the dust tail of Comet C/1995 O1 (Hale–Bopp) at high heliocentric distances
 |url          = https://arxiv.org/ftp/arxiv/papers/1404/1404.2562.pdf
 |journal      = Icarus
 |date         = July 2014
 |volume       = 236
 |pages        = 136–145
 |doi          = 10.1016/j.icarus.2014.03.033
 |arxiv        = 1404.2562
 |bibcode      = 2014Icar..236..136K
 |s2cid        = 119201510
 |access-date  = 2022-05-16
 |archive-date = 2022-10-07
 |archive-url  = https://web.archive.org/web/20221007113100/https://arxiv.org/ftp/arxiv/papers/1404/1404.2562.pdf
 |dead-url     = no
}}</ref>

<ref name="Vokrouhlicky2019">{{cite journal
  |first1 = David |last1 = Vokrouhlický
  |first2 = David |last2 = Nesvorný
  |first3 = Luke |last3 = Dones
  |title      = Origin and Evolution of Long-period Comets
  |journal    = The Astronomical Journal
  |date       = May 2019
  |volume     = 157
  |issue      = 5
  |page       = 10
  |id         = 181
  |doi-access = free
  |doi        = 10.3847/1538-3881/ab13aa
  |arxiv      = 1904.00728
  |bibcode    = 2019AJ....157..181V
  |s2cid      = 90261947}}</ref>

<ref name="Grundy2019">{{cite journal
  |first1 = W. M. |last1 = Grundy
  |first2 = K. S. |last2 = Noll
  |first3 = M. W. |last3 = Buie
  |first4 = S. D. |last4 = Benecchi
  |first5 = D. |last5 = Ragozzine
  |first6 = H. G. |last6 = Roe
  |title      = The mutual orbit, mass, and density of transneptunian binary Gǃkúnǁʼhòmdímà ({{mp|(229762) 2007 UK|126}})
  |journal    = Icarus
  |date       = December 2019
  |volume     = 334 
  |pages      = 30–38
  |doi        = 10.1016/j.icarus.2018.12.037
  |bibcode    = 2019Icar..334...30G
  |s2cid      = 126574999
  |url        = http://www2.lowell.edu/users/grundy/abstracts/preprints/2019.G-G.pdf
  |url-status = live
  |archive-url = https://web.archive.org/web/20190407045339/http://www2.lowell.edu/~grundy/abstracts/preprints/2019.G-G.pdf
  |archive-date = 7 April 2019}}</ref>

<ref name="Ridden-Harper2021">{{cite journal
  |first1 = Ryan |last1 = Ridden-Harper
  |first2 = Michele T. |last2 = Bannister
  |first3 = Rosita |last3 = Kokotanekova
  |title      = No Rotational Variability in C/2014 UN271 (Bernardinelli–Bernstein) at 23.8 au and 21.1 au as Seen by TESS
  |journal    = Research Notes of the AAS
  |date       = July 2021
  |volume     = 5
  |issue      = 7
  |page       = 161
  |doi-access = free
  |doi        = 10.3847/2515-5172/ac1512
  |bibcode    = 2021RNAAS...5..161R
  |s2cid      = 236166621}}</ref>

<ref name="Davies2021">{{cite journal
 |first        = John I.
 |last         = Davies
 |title        = News Feature: Mission to 2014 UN271 using OITS
 |url          = https://i4is.org/wp-content/uploads/2021/08/Principium34-print-2108231132opt.pdf
 |journal      = Principium
 |publisher    = Initiative for Interstellar Studies
 |date         = 24 August 2021
 |issue        = 34
 |pages        = 38–41
 |accessdate   = 12 February 2022
 |archive-date = 2022-03-13
 |archive-url  = https://web.archive.org/web/20220313102037/https://i4is.org/wp-content/uploads/2021/08/Principium34-print-2108231132opt.pdf
 |dead-url     = no
}}</ref>

<ref name="Hibberd2021">{{cite journal
 |first        = Adam
 |last         = Hibberd
 |title        = {{mp|2014 UN|271}} Spacecraft Missions
 |url          = https://i4is.org/wp-content/uploads/2021/08/2014-UN271-Spacecraft-Missions-Principium34-print-2108231132opt-7-1.pdf
 |journal      = Principium
 |publisher    = Initiative for Interstellar Studies
 |date         = 24 August 2021
 |issue        = 34
 |pages        = 42–48
 |accessdate   = 12 February 2022
 |archive-date = 2022-03-13
 |archive-url  = https://web.archive.org/web/20220313005319/https://i4is.org/wp-content/uploads/2021/08/2014-UN271-Spacecraft-Missions-Principium34-print-2108231132opt-7-1.pdf
 |dead-url     = no
}}</ref>

<ref name="Bernardinelli2021">{{cite journal
  |display-authors = etal
  |first1 = Pedro H. |last1 = Bernardinelli
  |first2 = Gary M. |last2 = Bernstein
  |first3 = Benjamin T. |last3 = Montet
  |first4 = Robert |last4 = Weryk
  |first5 = Richard |last5 = Wainscoat
  |title      = C/2014 UN271 (Bernardinelli–Bernstein): The Nearly Spherical Cow of Comets
  |journal    = The Astrophysical Journal Letters
  |date       = November 2021
  |volume     = 921
  |issue      = 2
  |pages      = 14
  |id         = L37
  |doi-access = free
  |doi        = 10.3847/2041-8213/ac32d3
  |arxiv      = 2109.09852
  |bibcode    = 2021ApJ...921L..37B
  |osti       = 1829535
  |s2cid      = 237581632}}</ref>

<ref name="Farnham2021">{{cite journal
  |first1 = Tony L. |last1 = Farnham
  |first2 = Michael S. P. |last2 = Kelley
  |first3 = James M. |last3 = Bauer
  |title      = Early Activity in Comet C/2014 UN271 Bernardinelli–Bernstein as Observed by TESS
  |journal    = The Planetary Science Journal
  |date       = December 2021
  |volume     = 2
  |issue      = 6
  |pages      = 8
  |id         = 236
  |doi-access = free
  |doi        = 10.3847/PSJ/ac323d
  |bibcode    = 2021PSJ.....2..236F
  |s2cid      = 244727277}}</ref>

<ref name="Bernardinelli2022">{{cite journal
  |display-authors = etal
  |first1 = Pedro H. |last1 = Bernardinelli
  |first2 = Gary M. |last2 = Bernstein
  |first3 = Masao |last3 = Sako
  |first4 = Brian |last4 = Yanny
  |title      = A search of the full six years of the Dark Energy Survey for outer Solar System objects
  |journal    = The Astrophysical Journal Supplement Series
  |date       = February 2022
  |volume     = 258
  |issue      = 2
  |pages      = 20
  |id         = 41
  |doi-access = free
  |doi        = 10.3847/1538-4365/ac3914
  |arxiv      = 2109.03758
  |bibcode    = 2022ApJS..258...41B
  |osti       = 1833281
  |s2cid      = 237440391}}</ref>

<ref name="Dybczynski2021">{{cite journal
  |first1 = Piotr A. |last1 = Dybczyński
  |first2 = Małgorzata |last2 = Królikowska
  |title      = The influence of individual stars on the long-term dynamics of comets C/2014 UN271 and C/2017 K2
  |url        = https://www.aanda.org/articles/aa/pdf/forth/aa43018-21.pdf
  |journal    = Astronomy & Astrophysics
  |date       = February 2022
  |volume     = forthcoming
  |pages      = 11
  |id         = 
  |doi-access = free
  |doi        = 10.1051/0004-6361/202143018
  |arxiv      = 2112.15353
  |bibcode    = 2022A&A...660A.100D
  |s2cid      = 245634341}}</ref>

<ref name="Lellouch2022">{{cite journal
 |first1       = E.
 |last1        = Lellouch
 |first2       = R.
 |last2        = Moreno
 |first3       = D.
 |last3        = Bockelée-Morvan
 |first4       = N.
 |last4        = Biver
 |first5       = P.
 |last5        = Santos-Sanz
 |title        = Size and albedo of the largest detected Oort-cloud object: comet C/2014 UN271 (Bernardinelli–Bernstein)
 |url          = https://www.aanda.org/articles/aa/pdf/2022/03/aa43090-22.pdf
 |journal      = Astronomy & Astrophysics
 |date         = March 2022
 |volume       = 659
 |pages        = 8
 |id           = L1
 |doi-access   = free
 |doi          = 10.1051/0004-6361/202243090
 |arxiv        = 2201.13188
 |bibcode      = 2022A&A...659L...1L
 |s2cid        = 246430382
 |access-date  = 2022-05-16
 |archive-date = 2022-05-18
 |archive-url  = https://web.archive.org/web/20220518122302/https://www.aanda.org/articles/aa/pdf/2022/03/aa43090-22.pdf
 |dead-url     = no
}}</ref>

<ref name="Marcin2022">{{cite journal
  |first = Wesołowski |last = Marcin
  |title      = Dust mass loss during the recent outburst of comet C/2014 UN271 Bernardinelli–Bernstein
  |journal    = Monthly Notices of the Royal Astronomical Society
  |date       = March 2022
  |volume     = 512
  |issue      = 4
  |pages      = 4683–4688
  |doi        = 10.1093/mnras/stac682
  |bibcode    = 2022MNRAS.tmp..662M
  |s2cid      = }}</ref>

<ref name="Hui2022">{{cite journal
  |first1 = Man-To |last1 = Hui
  |first2 = David |last2 = Jewitt
  |first3 = Liang-Liang |last3 = Yu
  |first4 = Max J. |last4 = Mutchler
  |title      = Hubble Space Telescope Detection of the Nucleus of Comet C/2014 UN271 (Bernardinelli–Bernstein)
  |journal    = The Astrophysical Journal Letters
  |date       = April 2022
  |volume     = 929
  |issue      = 1
  |pages      = 7
  |id         = L12
  |doi-access = free
  |arxiv      = 2202.13168
  |doi        = 10.3847/2041-8213/ac626a
  |bibcode    = 2022ApJ...929L..12H
  |s2cid      = 247158849}}</ref>

}} <!-- end of reflist -->

== 外部連結 ==
{{Commons|Category:C/2014 UN271 (Bernardinelli–Bernstein)}}
* [http://www.aerith.net/comet/catalog/2014UN271/2014UN271.html C/2014 UN271 (Bernardinelli–Bernstein)] {{Wayback|url=http://www.aerith.net/comet/catalog/2014UN271/2014UN271.html |date=20220214234940 }} – comet catalog page by Seiichi Yoshida, updated 5 February 2022
* [https://noirlab.edu/public/news/noirlab2119/ Giant Comet Found in Outer Solar System by Dark Energy Survey] {{Wayback|url=https://noirlab.edu/public/news/noirlab2119/ |date=20210710153504 }} – NOIRLab press release, 25 June 2021
* {{AstDys|2014UN271}}
* {{JPL small body|id=54161348}}

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[[Category:非週期彗星]]
[[Category:2014年發現的天體|20141020]]
[[Category:歐特雲]]
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