天鵝座X
天鵝座X是在星座天鵝座北部的一顆變星,英文縮寫為X Cyg。這是一顆仙王座δ型變星,其視星等的亮度範圍從5.85到6.91的,週期為16.386332天[3]。在最亮的時候,這顆恆星肉眼隱約可見。根據視差的量測,到這顆恆星的距離約為628光年[2]。它正以8.1km/s的徑向速度遠離我們[5]。這顆恆星很可能是疏散星團魯普雷希特173的成員[12]。
觀測資料 曆元 J2000 | |
---|---|
星座 | 天鵝座 |
星官 | |
赤經 | 20h 43m 24.192s[2] |
赤緯 | 35° 35′ 16.08″[2] |
視星等(V) | 5.85 to 6.91[3] |
特性 | |
光譜分類 | F7 Ib to G8 Ib[4] |
變星類型 | 仙王座δ[3] |
天體測定 | |
徑向速度 (Rv) | 8.1+0.2 −[5] km/s |
自行 (μ) | 赤經:−6.673 mas/yr 赤緯:−5.108 mas/yr |
視差 (π) | 0.8842 ± 0.0199[2] mas |
距離 | 3,690 ± 80 ly (1,130 ± 30 pc) |
絕對星等 (MV) | −4.53[6] |
詳細資料 | |
質量 | 7.9–8.9[7] M☉ |
半徑 | 95.9+1.6 −[8] R☉ |
表面重力 (log g) | 1.601[9] |
亮度 | 5,202[10] L☉ |
溫度 | 5,315+80 −[8] K |
金屬量 [Fe/H] | 0.10+0.08 −[8] dex |
自轉速度 (v sin i) | 8[7] km/s |
年齡 | 31[6] Myr |
其他命名 | |
參考資料庫 | |
SIMBAD | 資料 |
這顆恆星的變星光度是由小賽斯·卡羅·錢德勒於1886年發現的[13]。在1907年,埃德溫·布蘭特·弗羅斯特表明,天鵝座X是一顆F型恆星,具有不同的徑向速度,其行為類似於仙王座δ變星[14]。米歇爾·路易澤在1912年發現,這種變化的週期為16.38543天[15]。在1919年,弗蘭克·克雷格·喬丹確定恆星的色指數在每個週期中都會發生變化,隨着恆星變暗而變紅[16]。它被確定為滿足簡單周光關係的基準恆星類別經典造父變星的成員[17]。
在1954年,羅伯特·克拉夫特在峰值亮度下發現其恆星分類為F7-Ib[18],與F型超巨星的光譜相匹配。這顆恆星的光譜類型在脈動週期中變化,在最小亮度下低至G8 Ib[4]。在1956年,克拉夫特發現某些譜線加倍,他解釋說這是由於之前的脈動週期中,物質殼下落與光球碰撞的結果[19]。與大多數造父變星在每個週期經歷一次衝擊不同,天鵝座X被發現經歷了一次雙重衝擊[20]。
參考資料
編輯- ^ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, [30 December 2022], (原始內容存檔於2023-03-27).
- ^ 2.0 2.1 2.2 2.3 Brown, A. G. A.; et al. Gaia Early Data Release 3: Summary of the contents and survey properties. Astronomy & Astrophysics. 2021, 649: A1. Bibcode:2021A&A...649A...1G. S2CID 227254300. arXiv:2012.01533 . doi:10.1051/0004-6361/202039657 . 已忽略未知參數
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(幫助) (勘誤: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR. - ^ 3.0 3.1 3.2 Samus, N. N.; et al, General Catalogue of Variable Stars, Astronomy Reports, 5.1, 2017, 61 (1): 80–88, Bibcode:2017ARep...61...80S, S2CID 125853869, doi:10.1134/S1063772917010085.
- ^ 4.0 4.1 Kovtyukh, V. V.; et al, Phase-dependent Variation of the Fundamental Parameters of Cepheids. II. Periods Longer than 10 Days, The Astronomical Journal, January 2005, 129 (1): 433–453, Bibcode:2005AJ....129..433K, S2CID 120666782, doi:10.1086/426339 .
- ^ 5.0 5.1 Gontcharov, G. A., Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system, Astronomy Letters, November 2006, 32 (11): 759–771, Bibcode:2006AstL...32..759G, S2CID 119231169, arXiv:1606.08053 , doi:10.1134/S1063773706110065.
- ^ 6.0 6.1 Acharova, I. A.; et al, Galactic restrictions on iron production by various types of supernovae, Monthly Notices of the Royal Astronomical Society, 2012, 420 (2): 1590, Bibcode:2012MNRAS.420.1590A, S2CID 118404944, arXiv:1111.2152 , doi:10.1111/j.1365-2966.2011.20161.x.
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- ^ 8.0 8.1 8.2 Trahin, B.; et al, Inspecting the Cepheid parallax of pulsation using Gaia EDR3 parallaxes. Projection factor and period-luminosity and period-radius relations, Astronomy & Astrophysics, December 2021, 656, Bibcode:2021A&A...656A.102T, S2CID 244173657, arXiv:2111.09125 , doi:10.1051/0004-6361/202141680, A102.
- ^ Sprague, Dani; et al, APOGEE Net: An Expanded Spectral Model of Both Low-mass and High-mass Stars, The Astronomical Journal, March 8, 2022, 163 (4): 152, Bibcode:2022AJ....163..152S, ISSN 0004-6256, arXiv:2201.03661 , doi:10.3847/1538-3881/ac4de7 , eISSN 1538-3881.
- ^ Groenewegen, M. A. T., The flux-weighted gravity-luminosity relation of Galactic classical Cepheids, Astronomy and Astrophysics, 2020, 640: A113, Bibcode:2020A&A...640A.113G, S2CID 220364506, arXiv:2007.02148 , doi:10.1051/0004-6361/202038292.
- ^ [ 請檢查
|url=
值 (幫助). SIMBAD. 斯特拉斯堡天文資料中心. X Cyg] - ^ Anderson, Richard I.; et al, Cepheids in open clusters: an 8D all-sky census, Monthly Notices of the Royal Astronomical Society, September 2013, 434 (3): 2238–2261, Bibcode:2013MNRAS.434.2238A, arXiv:1212.5119 , doi:10.1093/mnras/stt1160.
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- ^ Frost, E. B., Nine stars having variable radial velocities, Astrophysical Journal, 1907, 25: 59–65, Bibcode:1907ApJ....25R..59F, doi:10.1086/141465.
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- ^ Kraft, Robert P., Double Lines in the Spectrum of the Classical Cepheid X Cygni, Publications of the Astronomical Society of the Pacific, April 1956, 68 (401): 137, Bibcode:1956PASP...68..137K, S2CID 122849355, doi:10.1086/126897 .
- ^ Gillet, D., Atmospheric dynamics in long-period Cepheids. Hα profile variations, Astronomy & Astrophysics, August 2014, 568, Bibcode:2014A&A...568A..72G, doi:10.1051/0004-6361/201423486 , A72.
- ^ Hintz, Eric G.; et al, An Examination of Pulsational Changes in the Classical Cepheid X Cygni, The Astronomical Journal, October 2021, 162 (4): 149, Bibcode:2021AJ....162..149H, S2CID 237553133, doi:10.3847/1538-3881/ac167f , 149.
- ^ Barmby, P.; et al, Galactic Cepheids with Spitzer. II. Search for Extended Infrared Emission, The Astronomical Journal, February 2011, 141 (2): 42, Bibcode:2011AJ....141...42B, S2CID 118581168, arXiv:1011.3386 , doi:10.1088/0004-6256/141/2/42, 42.
進階讀物
編輯- Wallerstein, G.; et al, The Behavior of the Paschen and Calcium Triplet Lines in Cepheid Variables II: The 16-day Variable X Cygni, Publications of the Astronomical Society of the Pacific, September 2019, 131 (1003): 094203, Bibcode:2019PASP..131i4203W, S2CID 201259492, doi:10.1088/1538-3873/ab1ec2 .
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- Wallerstein, G.; et al, A search for evidence of the neon-sodium cycle in the Cepheid X Cygni, Publications of the Astronomical Society of the Pacific, August 1984, 96: 613–617, Bibcode:1984PASP...96..613W, S2CID 120641485, doi:10.1086/131392.
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