He I and He II Intensities in Planetary Nebulae
نویسندگان
چکیده
منابع مشابه
HE I 2.06 Micron Emission from Nebulae
The spectrum emitted by any astronomical plasma is sensitive to a variety of details, some of which may not be obviously important. This paper describes the sensitivity of the He I 2.06 km line to the gas opacity at ionizing energies. The intensity of the line relative to a hydrogen line depends on the He`/H` ratio, but also on the ratio of continuous to He I Lya line opacity, since this determ...
متن کاملThe He ( I ) and He ( II ) Photoelectron Spectra of
U V photoelectron spectra of the title com pounds are rep orted . A ssignm ents are m ade with the help of H e(I)/H e(II) intensity differences, shift effects upon substitu tion and com parison with re la ted m olecules. Previously draw n conclusions about the electronic structure of similar com plexes also hold for the com pounds. It is indicated that the ionization energy for the sym m etri...
متن کاملTheoretical calculations of the H I , He I and He II free - bound continuous emission spectra
We present coefficients for the calculation of the continuous emission spectra of H I, He I and He II due to electron-ion recombination. Coefficients are given for photon energies from the first ionization threshold for each ion to the n = 20 threshold of hydrogen (36.5μ), and for temperatures 100 K ≤ T ≤ 10 K. The emission coefficients for He I are derived from accurate ab initio photoionizati...
متن کاملExperimental Stark Profile Determination of Some Plasma Broadened He I- and He II-Lines
für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...
متن کاملPatchy intergalactic He ii absorption in HE 2347 − 4342 ⋆
We report on observations of redshifted He ii 303.8 ˚ A absorption in the high-redshift QSO HE 2347−4342 (z = 2.885, V = 16.1) with the Goddard High Resolution Spectrograph on board HST in its low resolution mode (△λ = 0.7 ˚ A). With f λ = 3.6 10 −15 erg cm −2 s −1Å −1 at the expected position of He ii 304Å absorption it is the most UV-bright high redshift QSO discovered so far. We show that th...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1960
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/120.4.326