開普勒186f

開普勒186f^[1]^[2]
	開普勒186f 同地球嘅對比
發現
發現人	艾麗莎·金塔納
發現地方	開普勒太空天文台
發現日子	2014年4月17號
檢測方法	凌日法
軌道參數
半長軸	0.432 ± 0.01 AU
離心率	0.04
軌道週期	129.9444 ± 0.0012 d; 0.355772 y
軌道傾角	89.9
物理特徵
平均半徑	地球嘅 1.17 ± 0.08 倍
質量	地球嘅 1.4 倍
溫度	Teq: 188 K（−85 °C；−121 °F）

開普勒186f（英文：Kepler-186f或者KOI-571.05）係一粒兜住紅矮星開普勒186^[4]^[5]^[6]轉嘅系外行星，距離地球大約 580 光年。^[7]

佢出名嘅原因係因為佢嘅環境可能好似地球，佢係喺另一粒恆星嘅宜居帶入面發現第一粒半徑同地球好似嘅行星。NASA嘅開普勒太空望遠鏡用凌日法探測到佢，仲有另外四顆兜住開普勒186轉嘅行星（嗰啲行星都大過地球少少）。

開普勒望遠鏡望咗三年先搵到佢嘅訊號。結果最初是喺2014年3月19號嘅一次會議上公佈，當時媒體報導咗一啲細節。呢份公告喺2014年4月17號發布，之後登咗喺《科學》雜誌度。

宜居

畫家想像嘅開普勒186f

開普勒186f雖然喺宜居帶入面，但係都未必係宜居，大氣特徵都係宜居嘅條件，而我哋仲未知。Kepler-186f嘅距離太遠，依家嘅望遠鏡（例如 NESSI）或者下一代儀器（例如詹士韋伯太空望遠鏡）^[5]^[8]分析唔到佢嘅大氣層。^[9]

開普勒186f嘅半徑大過地球11%。佢嘅質量、密度同位置未知；如果呢個星球全部都係鐵，質量預估0.32 M⊕─3.77 M⊕（全為水或者冰嘅狀態）；如果組成同地球相近（1/3鐵、2/3矽組成嘅岩石），質量有可能會係1.44 M⊕。由氫同氦組成嘅厚重大氣層畀人認為冇可能喺半徑小過1.5 R⊕嘅行星形成。後生嘅紅矮星輻射嘅極紫外線量遠高過年老紅矮星，所以行星嘅原始大氣可能會喺紅矮星輻射大量極紫外線時遭到光致蒸發，令到大氣層入面大量嘅氫同氦剝離。

2018年6月，有一個研究發現開普勒186f可能有同地球上相似嘅季節同氣候，所以可能宜居。^[10]^[11]

研究

NASA系外行星探索計劃開普勒186f嘅「旅行海報」

搵外星人

SETI研究所試過用望遠鏡喺開普勒186f搵外星生命，截至2014年4月17號，艾倫望遠鏡陣列已經監聽咗開普勒186系統嘅無線電訊號大約一個月，最尾得個桔，乜嘢都搵唔到。

未來科技

Kepler-186f 距離我哋大約 580 光年（180 pc），距離依家嘅望遠鏡或者下一代計劃緊嘅望遠鏡嚟講太遠同埋佢嘅恆星太暗，確定唔到佢嘅質量或者佢有冇大氣層。但係Kepler-186f嘅發現令我哋知道，喺宜居帶入面仲有其他地球大細嘅行星。開普勒望遠鏡專注喺天空嘅一個細區，但係下一代行星搜尋太空望遠鏡，好似TESS同埋CHEOPS，會檢查成個天空入面嘅恆星。然後，詹士韋伯太空望遠鏡同未來嘅大型地面望遠鏡可以研究附近有行星嘅恆星，分析大氣、確定質量同埋推斷成分。^[12]除此之外，平方公里陣列可以顯著改善阿雷西博天文台同埋綠岸望遠鏡嘅射電觀測。^[13]

改名

一開始，呢粒行星入咗入開普勒輸入目錄（KIC）中，因為越嚟越多人研究佢，就入咗開普勒感興趣天體（KOI），開普勒186就由KIC 8120608變咗做KOI 571。開普勒186f喺度叫咗KOI-571-05 或者KOI-571.05。2013年，開普勒統一咗改名方法，就改咗做開普勒186f。

對比

以前知道喺宜居帶入面最接近地球大細嘅行星係有1.4 個地球咁大嘅開普勒62f。開普勒186f兜住著一粒M矮星轉，而開普勒62f就兜住一顆K型星轉。對G星（例如太陽）宜居帶入面地球大小行星嘅大氣演化研究發現，G星對啲行星來講啱啱好，咁樣可以冇咗初始吸積嘅氫包層，但留得返次級大氣，好似地球咁。^[14]

出名嘅系外行星
喺宜居帶嘅系外行星（開普勒-62e、開普勒62f、開普勒186f、開普勒296e、開普勒296f、開普勒438b、開普勒440b、開普勒442b） (開普勒望遠鏡喺2015年1月6號影嘅相).^[15]

流行文化

Kepler-186f係《文明：超越地球》遊戲入面其中一張系外行星地圖。^[16]

Kepler-186f係荷蘭搖滾樂隊 The Hubschrauber 2017年嘅專輯。^[17]

Kepler-186f喺Drew Haden Taylor寫嘅短篇小說《星星》入面，未來地球嘅殖民地。

睇埋

參考

↑ Quintana, E. V.; 等 (2014-04-18). Science. 344 (6181): 277–280. arXiv:1404.5667. Bibcode:2014Sci...344..277Q. PMID 24744370. S2CID 1892595. {{cite journal}}: Missing or empty |title= (help)
↑ Johnson, Michele; Harrington, J.D. (17 April 2014). "NASA's Kepler Discovers First Earth-Size Planet in The 'Habitable Zone' of Another Star". NASA. 原先內容歸檔喺2014-04-17.
↑ "Kepler-186 f". NASA Exoplanet Archive. 喺19 July 2016搵到.
↑ Chang, Kenneth (17 April 2014). "Scientists Find an 'Earth Twin', or Maybe a Wife". The New York Times.
↑ ^5.0 ^5.1 Chang, Alicia (17 April 2014). "Astronomers spot most Earth-like planet yet". Associated Press. 原先內容歸檔喺2014-04-18.
↑ Morelle, Rebecca (17 April 2014). "'Most Earth-like planet yet' spotted Helper the Kepler". BBC News. 原先內容歸檔喺2014-04-18.
↑ Bailer-Jones, C. A. L.; 等 (August 2018). "Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2". The Astronomical Journal. 156 (2): 58. arXiv:1804.10121. Bibcode:2018AJ....156...58B. doi:10.3847/1538-3881/aacb21. S2CID 119289017. Distance to Kepler 186, after taking into account light extinction
↑ Greenfieldboyce, Nell (17 April 2014). "Scientists Spot A Planet That Looks Like 'Earth's Cousin'". National Public Radio. 原先內容歸檔喺2014-04-18.
↑ Clark, Stephen (17 April 2014). "Earth's 'cousin' planet lies 500 light-years away". Spaceflight Now. 原先內容歸檔喺2014-04-18.
↑ Mack, Eric (29 June 2018). "Two Earth-like exoplanets (Kepler 186f and Kepler 62f) now even better spots to look for life – Two of the earliest Earth-ish exoplanet finds are now more exciting targets in the search for habitable worlds beyond this rock". CNET. 喺29 June 2018搵到.
↑ Shan, Yutong; Li, Gongjie (2018-05-16). "Obliquity Variations of Habitable Zone Planets Kepler-62f and Kepler-186f". The Astronomical Journal. 155 (6): 237. arXiv:1710.07303. Bibcode:2018AJ....155..237S. doi:10.3847/1538-3881/aabfd1. ISSN 1538-3881. S2CID 59033808.
↑ 引用錯誤無效嘅<ref>標籤；無文字提供畀叫做SETI-video嘅參照
↑ 引用錯誤無效嘅<ref>標籤；無文字提供畀叫做arxiv=1302.0845v1嘅參照
↑ Lammer, H.; Stökl, A.; Erkaev, N.V.; Dorfi, E.A.; Odert, P.; Güdel, M.; Kulikov, Yu.N.; Kislyakova, K.G.; Leitzinger, M. (13 January 2014). "Origin and Loss of nebula-captured hydrogen envelopes from "sub"- to "super-Earths" in the habitable zone of Sun-like stars". Monthly Notices of the Royal Astronomical Society. 439 (4): 3225. arXiv:1401.2765. Bibcode:2014MNRAS.439.3225L. doi:10.1093/mnras/stu085. S2CID 118620603.
↑ Clavin, Whitney; Chou, Felicia; Johnson, Michele (6 January 2015). "NASA's Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones". NASA. 喺6 January 2015搵到.
↑ "Civilization: Beyond Earth". Steam.
↑ "Nijmeegse band schiet album naar de maan". NOS op 3 (荷蘭文). Nederlandse Omroep Stichting. 25 January 2017. 喺31 July 2017搵到. Vernoemd naar de eerst ontdekte planeet waar misschien wel menselijk leven mogelijk is; Template:Google translation

出面網站

NASA – Mission overview.
NASA – Kepler Discoveries – Summary Table.
The NASA Exoplanet Archive 上面對 Kepler-186f 嘅講解.
The Exoplanet Data Explorer 對NASA – Kepler-186f 嘅講解.
NASA – Kepler-186f at The Extrasolar Planets Encyclopaedia.
Habitable Exolanets Catalog at UPR-Arecibo.
NASA – Kepler 186f – SETI Institute – A Planet in the Habitable Zone (video) 2014.
NASA – NASA Press kit.

[SCI-20140418-1] Quintana, E. V.; 等 (2014-04-18). Science. 344 (6181): 277–280. arXiv:1404.5667. Bibcode:2014Sci...344..277Q. PMID 24744370. S2CID 1892595. {{cite journal}}: Missing or empty |title= (help)

[NASA-20140417-2] Johnson, Michele; Harrington, J.D. (17 April 2014). "NASA's Kepler Discovers First Earth-Size Planet in The 'Habitable Zone' of Another Star". NASA. 原先內容歸檔喺2014-04-17.

[NASAExoplanet-3] "Kepler-186 f". NASA Exoplanet Archive. 喺19 July 2016搵到.

[NYT-20140417-4] Chang, Kenneth (17 April 2014). "Scientists Find an 'Earth Twin', or Maybe a Wife". The New York Times.

[AP-20140417-5] 5.0 ^5.1 Chang, Alicia (17 April 2014). "Astronomers spot most Earth-like planet yet". Associated Press. 原先內容歸檔喺2014-04-18.

[BBC-20140417-6] Morelle, Rebecca (17 April 2014). "'Most Earth-like planet yet' spotted Helper the Kepler". BBC News. 原先內容歸檔喺2014-04-18.

[Gaia_DR2_Specific4Distances-7] Bailer-Jones, C. A. L.; 等 (August 2018). "Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2". The Astronomical Journal. 156 (2): 58. arXiv:1804.10121. Bibcode:2018AJ....156...58B. doi:10.3847/1538-3881/aacb21. S2CID 119289017. Distance to Kepler 186, after taking into account light extinction

[NPR-303806575-8] Greenfieldboyce, Nell (17 April 2014). "Scientists Spot A Planet That Looks Like 'Earth's Cousin'". National Public Radio. 原先內容歸檔喺2014-04-18.

[Clark-2014-9] Clark, Stephen (17 April 2014). "Earth's 'cousin' planet lies 500 light-years away". Spaceflight Now. 原先內容歸檔喺2014-04-18.

[CNET-20180629-10] Mack, Eric (29 June 2018). "Two Earth-like exoplanets (Kepler 186f and Kepler 62f) now even better spots to look for life – Two of the earliest Earth-ish exoplanet finds are now more exciting targets in the search for habitable worlds beyond this rock". CNET. 喺29 June 2018搵到.

[11] Shan, Yutong; Li, Gongjie (2018-05-16). "Obliquity Variations of Habitable Zone Planets Kepler-62f and Kepler-186f". The Astronomical Journal. 155 (6): 237. arXiv:1710.07303. Bibcode:2018AJ....155..237S. doi:10.3847/1538-3881/aabfd1. ISSN 1538-3881. S2CID 59033808.

[SETI-video-12] 引用錯誤無效嘅<ref>標籤；無文字提供畀叫做SETI-video嘅參照

[arxiv=1302.0845v1-13] 引用錯誤無效嘅<ref>標籤；無文字提供畀叫做arxiv=1302.0845v1嘅參照

[arXiv-2765-14] Lammer, H.; Stökl, A.; Erkaev, N.V.; Dorfi, E.A.; Odert, P.; Güdel, M.; Kulikov, Yu.N.; Kislyakova, K.G.; Leitzinger, M. (13 January 2014). "Origin and Loss of nebula-captured hydrogen envelopes from "sub"- to "super-Earths" in the habitable zone of Sun-like stars". Monthly Notices of the Royal Astronomical Society. 439 (4): 3225. arXiv:1401.2765. Bibcode:2014MNRAS.439.3225L. doi:10.1093/mnras/stu085. S2CID 118620603.

[NASA-20150106-15] Clavin, Whitney; Chou, Felicia; Johnson, Michele (6 January 2015). "NASA's Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones". NASA. 喺6 January 2015搵到.

[16] "Civilization: Beyond Earth". Steam.

[17] "Nijmeegse band schiet album naar de maan". NOS op 3 (荷蘭文). Nederlandse Omroep Stichting. 25 January 2017. 喺31 July 2017搵到. Vernoemd naar de eerst ontdekte planeet waar misschien wel menselijk leven mogelijk is; Template:Google translation

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