منابع مشابه
High mass - loss carbon stars and the evolution of the local 12 C / 13 C ratio
The 12 C/ 13 C ratio has been measured in a sample of 10 carbon stars with high mass-loss rates, of ≥ 10 −5 M yr −1. This sample is complete for northern hemisphere carbon stars within ∼ 1 kpc of the Sun. Using the J=2–1 rotational lines of CO and 13 CO, the intensity ratio of 12 CO/ 13 CO is found to be 17 ± 11 for the sample, and the deduced 12 C/ 13 C abundance ratio, after corrections for C...
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Isotope Ratio Mass Spectrometry (IRMS) is a specialized technique used to provide information about the geographic, chemical, and biological origins of substances. The ability to determine the source of an organic substance stems from the relative isotopic abundances of the elements which comprise the material. Because the isotope ratios of elements such as carbon, hydrogen, oxygen, sulfur, and...
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We first discuss the mass range of type IIP SN progenitors and how the upper and lower limits impose interesting constraints on stellar evolution. Then we discuss the possible implications of two SNe, 2002ap and 2006jc, for Wolf-Rayet star mass-loss rates and long Gamma-ray bursts.
متن کاملCepheid Mass-loss and the Pulsation – Evolutionary Mass Discrepancy
I investigate the discrepancy between the evolution and pulsation masses for Cepheid variables. A number of recent works have proposed that non-canonical mass-loss can account for the mass discrepancy. This mass-loss would be such that a 5M⊙ star loses approximately 20% of its mass by arriving at the Cepheid instability strip; a 14M⊙ star, none. Such findings would pose a serious challenge to o...
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The material described in this thesis is the result of an internship of the master study Business Analytics. It has been conducted at FRISS from April 5, 2015 until December 4, 2015. FRISS is a consultancy and software company specialized in fraudand risk management for the insurance sector and is located in Utrecht, the Netherlands. The main research problem described in this thesis is how to ...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1981
ISSN: 0252-9211
DOI: 10.1017/s0252921100095270