Results 131 to 140 of about 1,995 (163)
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Seismological measurement of stellar ages
Nature, 1987Accurate measurements of stellar acoustic oscillation frequencies, which are likely to be obtained in the coming years, will provide important new data enabling us to diagnose the internal structure of stars. The ages of main-sequence stars are likely to be determined to a higher precision than has been possible in the past and much more accurate ...
D O Gough, Gough Douglas
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Preparation of Ag Stellar Dendrites: Modeling the Growth of Stellar Snowflakes
Crystal Growth & Design, 2014The synthesis of Ag stellar dendrites was achieved using a solution-phase method by modeling the growth of stellar snowflakes. In the synthesis, 2,3-bis(2-pyridyl)pyrazine (dpp) acted as the growth-directing agent, forming hexagonal structures that served as the nuclei for the growth of stellar dendrites.
Choon Hwee Bernard Ng, Wai Yip Fan
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THE OLDEST STELLAR POPULATIONS AND THE AGE OF THE UNIVERSE
EAS Publications Series, 2002The study of the oldest stellar populations in the Galaxy provides important cosmological information (e.g. a lower limit to the age of the Universe) and helps constraining models of galaxy formation. The most commonly used stellar age indicators are reviewed and discussed, and the impact of GAIA on these topics is estimated.
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Stellar Age and Mass Determination
2012We outline a Bayesian method to determine stellar ages and masses from observationally derived surface luminosities and effective temperatures. We then illustrate the procedure with two test stars.
{Mowlavi} N., {Eyer} L.
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Stellar Rotation and Age Determination
EAS Publications Series, 2010In this preliminary analysis we discuss on a statistical inversion method applied to the measured stellar V rot sin i . Our goal is to obtain the V rot of the cluster stars which is a key parameter of stellar evolution computations.
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Stellar ages and their cosmological context
EAS Publications Series, 2014Stellar ages have traditionally been used to constrain cosmological models by setting lower limits to the age of the universe. We quickly review the basic cosmological concepts that underpin the derivation of a finite age, and the constraints given by the measure of cosmological parameters at a redshift z ∼ 1000.
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Variation of stellar coronal activity with age
Astrophysics and Space Science, 1988We investigate the variation in coronal activity of late-type stars with age. We determine the age of the star from the colour-colour diagram (U-B vsB-V). We show that the ratio of X-ray luminosity (Lx) to bolometric luminosity (Lbol) is well correlated with age over several orders of magnitude variations. We find thatLx/Lbol) decreases with age with a
P. K. Kunte, A. R. Rao, M. N. Vahia
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On local stellar age distributions and the history of the stellar birthrate in the galactic disk
Astronomische Nachrichten, 1991AbstractThe fraction of nearby stars born at different galactocentric radii is roughly estimated using the epicyclic approximation of stellar orbits in the galactic disk. Especially, the question of a possible burst origin of features in the local stellar age distribution is discussed.
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