大溪天文台觀測日誌:2019年11月09日大溪 晴 近滿月 東北季風強陣風
溫度:18.7度c. 濕度:63% 視狀 1/5 透明度 1/5 (1-5 最差到最佳程度)
天鵝座 CYG 狐狸座 VUL 脈動變星群
MEADE 10" SCT F/6.3 曝光 60秒 SBIG ST2000XM V FILTER 自由追蹤 (POLEMASTER 2017 0805 校對) Showa 20E kai +Vixen Skysensor 2000PC +TheSky GOTO system
觀測變星數:17顆 CCD:11顆 目視:6顆
Observations submitted since last login:
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Name JD CalendarDate Mag V/VIS a b inst SQM
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R CYG 2458796.98472 2019 Nov 9.4847 10.4 V 17.3
U CYG 2458797.00556 2019 Nov 9.5056 10.7 V 17.46
V CYG 2458797.01250 2019 Nov 9.5125 8.9 V 17.41
Z CYG 2458797.03333 2019 Nov 9.5333 11.6 V 17.36
CH CYG 2458797.04514 2019 Nov 9.5451 8.9 V 17.46
CH CYG 2458797.04931 2019 Nov 9.5493 8.6 Vis. 6.51 8.8 8cm REFRACTOR 19X 17.46
T CYG 2458796.96667 2019 Nov 9.4667 5.3 Vis. 5.47 6.42 8X30 BINOCULAS NIKON FOV 8.3d -----
W CYG 2458796.97361 2019 Nov 9.4736 6.05 Vis. 3.98 6.27 8X30 BINOCULAS NIKON 17.38
X CYG 2458796.98125 2019 Nov 9.4813 6.4 Vis. 4.53 6.7 8CM REFRACTOR 19X 17.51
Y CYG 2458796.98750 2019 Nov 9.4875 6.9 Vis. 6.64 7.95 8CM REFRACTOR 19X 17.46
T VUL 2458797.06389 2019 Nov 9.5639 5.6 Vis. 5.03 6.5 8X30 BINOCULAS NIKON 17.22
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10" SCT F/6.3 +ST2000XM 直焦點 溫度+0度C 曝光 60-70秒 JOHNSON V FILTER
AAVSO Observatory Code : TYGA TW (大溪天文台 台灣)
當晚極限星等 取樣 1109:14.72mag
大溪及世界各地業餘觀測者的觀測資料及曲線可參考 http://www.aavso.org/data/lcg
*.Vmag=photometry RADEC=astrometry by Astroart5.0
CH CYG:The symbiotic variable star CH Cygni is a rewarding star to observe and a puzzling one to study due to its erratic light variations and peculiar spectra. This month, observers in the northern latitudes are best situated to find CH Cyg flying high in the constellation Cygnus just under the western wingtip of the Swan, two degrees south-southwest of Iota Cygni. The American Association of Variable Star Observers has recorded the brightness of CH Cyg from as bright as magnitude 5.6, when it can be seen with the naked eye, to as faint as 10.5 in 1997, when it became a challenge for binoculars. For the past decade or so, it has stayed around the faint end of this range, but this unpredictable star often rises or fades sharply in just a month or two providing a treat to watchful observers.
How can one star exhibit a spectral profile that exhibits features from two very different types of stars? The generally accepted answer is simply that a symbiotic system is two very different stars, stars that are close enough to each other to form an interacting binary system. Paul Merrill borrowed the term "symbiosis" from biology, where it signifies the co-existence of different types of organisms to their mutual advantage. The astronomical analogy is appropriate since a symbiotic star system is usually comprised of two very different types of stars - a cool red giant star and a hot compact object (probably a white dwarf)- existing together by exchanging mass in their evolutionary stages. These stars are embedded in a gas shell, or nebula. The source of the nebulosity is the red giant star, which loses considerable amounts of mass either through a stellar wind or through pulsation. Moreover, symbiotic stars can be divided into two main types: those with dust emission and those without it. Some of those with dust emission also have radio emission (CH Cyg is an example).
天鵝座CH 變星本身是一顆非常有趣的共生雙星形變星(symbiosis variable star).簡單說就是兩顆性質不同的恆星(如這顆變星ＣＨ CYG 是由紅巨星和一顆高密度的恆星(白矮星所組成)),因為兩顆距離粉近到會互相影響吸引.產生一些讓變星觀測者粉有看頭的亮度變化 (5.6-10.5 等範圍)...通常這顆變星處於黯淡的狀態,等到白矮星產生吸收紅巨星能量到臨界點產生爆炸!(本年7月產生一次爆發)於是會在一個月內亮度急速上升到達最亮的亮度階段.也類同的新星的現象.
紅巨星通常是 提供大量的能量轉移到白矮星的爆發活動期間,可由觀測光譜的短波長藍色光譜和金屬等 H，He，FeII和CaII的發射譜位移變化作為共生雙星的性質.
翻譯 de 曹大貓咪
https://www.aavso.org/vsots_chcyg
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