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$doc.title

... universe was much more active in the past (z ~1 - 2) but what happens earlier is unclear There are many complications of interpretation, including the reliability of each SFR ...
Week 2
Week 2

A New Hypothesis On The Origin and Formation of The Solar And
A New Hypothesis On The Origin and Formation of The Solar And

PDF only - at www.arxiv.org.
PDF only - at www.arxiv.org.

... we also know that earlier answers were quite wrong. The problem of the source of solar energy became an important part of physics and astronomy only with the emergence of the law of energy conservation in the 1840s. The first theory of solar heat based on the new law, due to J. R. Mayer, assumed the ...
NuSeti_Harvard_CLub_8-31
NuSeti_Harvard_CLub_8-31

... This suggests use of neutrinos from the decay of Z as an ideal carrier. (open problem: how to make Z-clocks!) We imagine that an ETI is doing just that at distances of order of kiloparsecs in the galaxy for its own spread out outposts… We expect to see neutrinos of energy of about 45.5 GeV. To get ...
Untitled
Untitled

... sword form The Pot or The Saucepan, now tilted on its side. In early June Orion can be seen both in the west at dusk and in the east at dawn. The Orion Nebula is visible in binoculars as a misty glow around the middle stars of Orion's Sword or the handle of The Pot. It is a vast cloud of dust and ga ...
News from high-mass twin stars
News from high-mass twin stars

... The pomerons (wavy lines) couple to different quarks (solid lines) in quark matter (as in the hNJL Lagrangian) or to quarks in different baryons in nuclear matter (giving rise to repulsive 3- and 4- body interactions). ...
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... Stellar Response vs. Roche Radius • Since the more massive star evolves first, it will be the one to first fill the Roche Radius • The resulting transfer is thus from massive to less massive star (e.g. a 2M to a 1M ). • Secular stability requires that the donor star stay within the Roche radius a ...
Outlook: Disk structure models
Outlook: Disk structure models

... The basic model - disk masses: 10-4 - 0.01 M Sun - elemental abundances: molecular cloud abundances ...
In Pictures: Journey to the Stars
In Pictures: Journey to the Stars

... are many more in the universe. But did you know that a long, long time ago, there were no stars at all? Gravity is the force of attraction between all objects in the © AMNH ...
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Synthetic Stellar Populations Encyclopedia of Astronomy & Astrophysics eaa.iop.org Guy Worthey

... not unique. For instance, the spectrum of a G dwarf closely resembles that of a G giant, and replacement of one by the other probably will not noticeably affect the goodness of fit. Second, information on galaxy age or metal abundance requires interpretation. Suppose the synthesis says that G0 dwarf ...
Using First-Order Logic
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Chapter 14 The Solar System
Chapter 14 The Solar System

... Neptune is a cold, blue planet. Its atmosphere contains visible clouds. ...
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Unresolved Stellar Populations

... From theory, one can determine L̄ (the so-called SBF luminosity) for an SSP or CSP, provided its age and metallicity or the SFH are known, and an IMF is adopted. Once L̄ is determined, σ2 the observed F̄F immediately provides the distance D. The method clearly works best when observing the external ...
Bob Mathieu (Wisconsin) – Observations of Open Clusters
Bob Mathieu (Wisconsin) – Observations of Open Clusters

... Witte & Savonije 2002 Claret & Cunha 1997 (Zahn 1977) ...
Understanding Precession of the Equinox
Understanding Precession of the Equinox

BOSS	DR12:	Clustering	of galaxies	&Dark	Matter halos Sergio	Rodríguez-Torres
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... collisions effect. • HAM provides good predictions for 2-point and 3-point statistics, using one single parameter. • Halo occupation distribution and halo to stellar mass relation are in agreement with previous works. • Modification of the standard HAM can be a powerful tool to study the clustering ...
JSK_PPV_poster - The Formation & Evolution of Planetary
JSK_PPV_poster - The Formation & Evolution of Planetary

... assemblages around our target stars that are within factors of 2 - 3 of the observed fluxes. We infer that these systems have outer remnant planetesimal belts that are consistent in scale and starting masses to our KB. 6. The absence of a disk around the ~1 Gyr old star HD 13974 suggests that either ...
Introduction: The Night Sky
Introduction: The Night Sky

... At end of helium fusion star has lost all its outer layers ...
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... number in F isotopes ...
Introductory Presentation on Cosmic Rays
Introductory Presentation on Cosmic Rays

... are accelerated by shock waves traveling through the Corona and by magnetic energy released in Solar flares. The Solar Wind contains roughly equal numbers of electrons and protons along with heavier ions and blows continuously from the Sun at an average speed of 400 km/sec. This leads to a mass loss ...
Powerpoint for today
Powerpoint for today

... Escape velocity from Earth's surface is 11 km/sec. If Earth were crushed down to 1 cm size, escape velocity would be speed of light. Then nothing, including light, could escape Earth. This special radius, for a particular object, is called the Schwarzschild Radius, RS. RS  M. ...
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Standard solar model

The standard solar model (SSM) is a mathematical treatment of the Sun as a spherical ball of gas (in varying states of ionisation, with the hydrogen in the deep interior being a completely ionised plasma). This model, technically the spherically symmetric quasi-static model of a star, has stellar structure described by several differential equations derived from basic physical principles. The model is constrained by boundary conditions, namely the luminosity, radius, age and composition of the Sun, which are well determined. The age of the Sun cannot be measured directly; one way to estimate it is from the age of the oldest meteorites, and models of the evolution of the Solar System. The composition in the photosphere of the modern-day Sun, by mass, is 74.9% hydrogen and 23.8% helium. All heavier elements, called metals in astronomy, account for less than 2 percent of the mass. The SSM is used to test the validity of stellar evolution theory. In fact, the only way to determine the two free parameters of the stellar evolution model, the helium abundance and the mixing length parameter (used to model convection in the Sun), are to adjust the SSM to ""fit"" the observed Sun.
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