scholarly journals The chemical composition of the Sun

2010 ◽  
pp. 177-182
Author(s):  
N. Grevesse ◽  
M. Asplund ◽  
A. J. Sauval ◽  
P. Scott
Keyword(s):  
Chemical Composition ◽  
The Sun

The chemical composition of solar-type stars in comparison with that of the Sun

2010 ◽  
pp. 183-189
Author(s):  
Bengt Gustafsson ◽  
Jorge Meléndez ◽  
Martin Asplund ◽  
David Yong
Keyword(s):  
Chemical Composition ◽  
The Sun ◽  
Solar Type

Note on the Chemical Composition of the Sun.

1950 ◽  
Vol 111 ◽  
pp. 446
Author(s):  
Marjorie Hall Harrison
Keyword(s):  
Chemical Composition ◽  
The Sun

scholarly journals Unprecedented accurate abundances: signatures of other Earths?

2009 ◽  
Vol 5 (S265) ◽  
pp. 412-415
Author(s):  
Jorge Meléndez ◽  
Martin Asplund ◽  
Bengt Gustafsson ◽  
David Yong ◽  
Iván Ramírez
Keyword(s):  
Chemical Composition ◽  
Giant Planets ◽  
Elemental Abundance ◽  
The Sun ◽  
Volatile Elements ◽  
Solar Abundance ◽  
Abundance Pattern ◽  
Refractory Elements ◽  
Solar Type ◽  
Solar Analogs

AbstractFor more than 140 years the chemical composition of our Sun has been considered typical of solar-type stars. Our highly differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to solar twins, shows that the Sun has a peculiar chemical composition with a ≈20% depletion of refractory elements relative to the volatile elements in comparison with solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. A similar study of solar analogs from planet surveys shows that this peculiarity also holds in comparisons with solar analogs known to have close-in giant planets while the majority of solar analogs without detected giant planets show the solar abundance pattern. The peculiarities in the solar chemical composition can be explained as signatures of the formation of terrestrial planets like our own Earth.

scholarly journals Pu-erh tea: Fermentative process as a potentialized of sensory aspects and bioactive profile – a review

2021 ◽  
Vol 10 (8) ◽  
pp. e3510816999
Author(s):  
Rafaela Julyana Barboza Devos ◽  
Cristina de Araújo Barth ◽  
Aline Dettmer ◽  
Telma Elita Bertolin ◽  
Luciane Maria Colla
Keyword(s):  
Amino Acids ◽  
Chemical Composition ◽  
Green Tea ◽  
Scientific Evidence ◽  
Market Value ◽  
Chemical Components ◽  
The Sun ◽  
Red Color ◽  
Tea Production ◽  
Fermentative Process

Pu-erh is a fermented Chinese tea with characteristics of mild, woody flavor and dark red color. The preparation of the tea starts from leaves of Camellia sinensis in natura that undergo a drying in the sun. Its classification is given in two categories: a raw tea similar to green tea and a matured tea that is fermented. Matured tea has a higher market value due to the processes involved in manufacturing, especially in terms of aging. Pu-erh has numerous benefits for human health, which are closely related to the bioactive profile of the main chemical components of tea, being polyphenols, theabrownins, flavonols, polysaccharides, amino acids and alkaloids. The increasing introduction of Pu-erh tea in the diet of consumers results in the need to explore information associated with consumption through analysis of the available literature, addressing current scientific evidence. Therefore, the present review sought to elucidate the fermentative process of Pu-erh tea production, its chemical composition, its sensory aspects and health benefits.

Differential Curve-of-Growth Analyses of Mn-Hg Stars

1976 ◽  
Vol 32 ◽  
pp. 521-531
Author(s):  
Keiichi Kodaira
Keyword(s):  
Chemical Composition ◽  
Effective Temperature ◽  
Narrow Range ◽  
Enrichment Factors ◽  
Surface Gravity ◽  
List Type ◽  
The Sun ◽  
Type Number ◽  
Growth Method ◽  
Growth Analyses

SummarySpectra of eleven Mn-Hg stars (α And,μ Lep, 129 Tau, 14 Hya,κCnc, 30 UMa, πBoo, ι CrB, ϕ Her, ν Her, 46 Dra) are analyzed by the curve-of-growth method. The effective temperature and the surface gravity are estimated from the |u-b|- and the β-indexes and fall into ranges O.346 ≤ θe≤0.451 and 3.4≤log g≤3.8. The microturbulence velocity is found to be in a narrow range of 2 ≲ vt≲ 4.5 km/sec. The resulting chemical composition is very similar among the eleven Mn-Hg stars and shows following characteristics:1)The abundance ratios N(C):N(Si):N(Ca):N(Fe), N(Ti):N(Cr) and N(Sr):N(Y):N(Zr) are nearly identical to those of the sun.2)The enrichment factors relative to Fe are about 10 for Ti and Cr, about 100 for P, Sc, Mn, Sr, Y, and Zr, about 105for Ga, and about 103~106(varying among stars) for Hg.

scholarly journals The most oxygen-poor planetary nebula: AGB nucleosynthesis at low metallicities

2009 ◽  
Vol 5 (S265) ◽  
pp. 94-97
Author(s):  
G. Stasińska ◽  
C. Morisset ◽  
G. Tovmassian ◽  
T. Rauch ◽  
T. Decressin
Keyword(s):  
Chemical Composition ◽  
Planetary Nebula ◽  
Galactic Halo ◽  
The Sun ◽  
Stellar Rotation ◽  
Abundance Pattern ◽  
Oxygen Abundance

AbstractTS01 is an exceptional planetary nebula (PN) in the Galactic halo: it is the most oxygen-poor and has a double-degenerate core with mass close to 1.4M⊙, possibly a Supernova Ia progenitor. With data from the far UV to the IR we can pin down the abundances of half a dozen of elements. The oxygen abundance is by 1.9(±0.3) dex lower than in the Sun. Standard AGB models with appropriate mass and metallicity cannot explain the observed chemical composition. We find that additional mixing, induced by stellar rotation and/or by the presence of the close companion can explain most of the features of the abundance pattern in TS01.

Earth's thermospheric evolution and implications for planetary habitability

2020 ◽  
Author(s):  
Colin Johnstone
Keyword(s):  
Carbon Dioxide ◽  
Solar Wind ◽  
Chemical Composition ◽  
Solar System ◽  
Planetary Atmospheres ◽  
Upper Atmosphere ◽  
The Sun ◽  
The Earth ◽  
First Time ◽  
Planetary Habitability

<p>During the Archean eon from 3.8 to 2.5 billion years ago, the Earth's upper atmosphere and interactions with the magnetosphere and the solar wind were likely significantly different to how it is today due to major differences in the chemical composition of the atmosphere and the younger Sun being signifcantly more active. Understanding these factors is important for understanding the evolution of planetary atmospheres within our solar system and beyond. While the higher activity of the Sun would have caused additional heating and expansion of the atmosphere, geochemical measurements show that carbon dioxide was far more abundant during this time and this would have led to significantly thermospheric cooling which would have protected the atmosphere from losses to space. I will present a study of the effects of the carbon dioxide composition and the Sun's activity evolution on the thermosphere and ionosphere of the Archean Earth, studying for the first time the effects of different scenarios for the Sun's activity evolution. I will show the importance of these factors for the exosphere and escape processes of the Earth and terrestrial planets outside our solar system.</p>

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