Element Segregation in Low Metallicity Stars and the Primordial
... stars, they found the following characteristic behavior : for very small mass loss rates, the surface lithium abundance is depleted due to element settling. Increasing the mass loss rate contradicts the settling and the surface lithium abundance first increases. It goes through a maximum for a rate ...
... stars, they found the following characteristic behavior : for very small mass loss rates, the surface lithium abundance is depleted due to element settling. Increasing the mass loss rate contradicts the settling and the surface lithium abundance first increases. It goes through a maximum for a rate ...
Comparison of low- and high-mass star formation
... are evolving constantly, with mass growing (from converging or collapsing flow) and depleting (into one or more collapsed objects) at the same time. The replenishment of dense gas in the “core” is the key to the long duration of high mass accretion rate for the most massive object, which is many tim ...
... are evolving constantly, with mass growing (from converging or collapsing flow) and depleting (into one or more collapsed objects) at the same time. The replenishment of dense gas in the “core” is the key to the long duration of high mass accretion rate for the most massive object, which is many tim ...
1. The catalogue structure
... the tip of the tail” in the Almagest. In the canonical version of the Almagest ([1339]) verbal descriptions of stars were taken from the Latin edition of 1528 translated by Trebizond. They were verified by the Greek edition. It is believed that the initial language of the Almagest was Greek. See Cha ...
... the tip of the tail” in the Almagest. In the canonical version of the Almagest ([1339]) verbal descriptions of stars were taken from the Latin edition of 1528 translated by Trebizond. They were verified by the Greek edition. It is believed that the initial language of the Almagest was Greek. See Cha ...
Ancient Egyptian Astronomy
... Early Indian Astronomers and their Discoveries Many of the earliest Indian astronomers made discoveries that were far ahead of their western counterparts. Aryabhatta - was born in 476 A.D., and is widely recognized as the father of Indian astronomy. When he was about 25 years old, he presented astro ...
... Early Indian Astronomers and their Discoveries Many of the earliest Indian astronomers made discoveries that were far ahead of their western counterparts. Aryabhatta - was born in 476 A.D., and is widely recognized as the father of Indian astronomy. When he was about 25 years old, he presented astro ...
Origin of the Chemical Elements
... Chemical elements are central for the existence of life and the richness and variety of our environment. Therefore, one of the basic questions concerns the origin of the chemical elements. The answer is complex because it relies on dynamical processes from elementary particles and nuclei to stars an ...
... Chemical elements are central for the existence of life and the richness and variety of our environment. Therefore, one of the basic questions concerns the origin of the chemical elements. The answer is complex because it relies on dynamical processes from elementary particles and nuclei to stars an ...
PDF - Department of Statistics
... As we state above, the strict validity of this method of determining a threshold assumes that the statistics Yksh have the same distribution, for fixed k. In reality this will probably not be exactly the case, in particular because of the effects of crowding. Although our standardization takes accou ...
... As we state above, the strict validity of this method of determining a threshold assumes that the statistics Yksh have the same distribution, for fixed k. In reality this will probably not be exactly the case, in particular because of the effects of crowding. Although our standardization takes accou ...
Stars & Galaxies - newmanlib.ibri.org
... they tend to have a rather spherical shape. • They are much larger and more tightly packed than galactic clusters,typically having tens of thousands of stars. • They move in a halo around the galaxy rather than in the galactic plane. ...
... they tend to have a rather spherical shape. • They are much larger and more tightly packed than galactic clusters,typically having tens of thousands of stars. • They move in a halo around the galaxy rather than in the galactic plane. ...
The 2008 RBSE Journal - National Optical Astronomy Observatory
... that is produced by jets produced by active galactic nucleus that is not in the Milky Way. This happens when an accretion disk forms around a black hole and spins, converts gravitational and rotational energy into excess perpendicular to the disk. Although DRAGNs are found in starburst galaxies, whi ...
... that is produced by jets produced by active galactic nucleus that is not in the Milky Way. This happens when an accretion disk forms around a black hole and spins, converts gravitational and rotational energy into excess perpendicular to the disk. Although DRAGNs are found in starburst galaxies, whi ...
1 A Re-appraisal of the Habitability of Planets Around M Dwarf Stars
... IV, V runs from Supergiant to dwarf. Our own Sun is spectral type G2 and luminosity class V (or dwarf). Less massive dwarf stars are cool, such as M dwarfs. The length of time a particular star remains on the main sequence, and the rate at which the end phases of its evolution cause it to expand, co ...
... IV, V runs from Supergiant to dwarf. Our own Sun is spectral type G2 and luminosity class V (or dwarf). Less massive dwarf stars are cool, such as M dwarfs. The length of time a particular star remains on the main sequence, and the rate at which the end phases of its evolution cause it to expand, co ...
Stellar Metamorphosis as Alternative to Nebular Hypothesis
... momentum loss of the Sun.[5] If the nebular model were correct and all the material in the solar system was formed from a giant spinning gas/dust cloud, then the Sun should have the majority of the angular momentum. This means it should spin much more rapidly. The mathematical models have failed to ...
... momentum loss of the Sun.[5] If the nebular model were correct and all the material in the solar system was formed from a giant spinning gas/dust cloud, then the Sun should have the majority of the angular momentum. This means it should spin much more rapidly. The mathematical models have failed to ...
A Compilation of Relevant Articles from MMM`s first 25 years, issues
... the Full Moon, or some 10,000 times brighter than Sirius. To receive only as much sunlight as Earth does, a planet would have to orbit Deneb or Rigel more than 8 times farther out than Neptune from the Sun! In our corner of the Galaxy, F+ Deneb, Rigel, and Canopus dominate all the space within 2,000 ...
... the Full Moon, or some 10,000 times brighter than Sirius. To receive only as much sunlight as Earth does, a planet would have to orbit Deneb or Rigel more than 8 times farther out than Neptune from the Sun! In our corner of the Galaxy, F+ Deneb, Rigel, and Canopus dominate all the space within 2,000 ...
The figure below shows what scientists over 1000 years ago thought
... Use words or phrases from the box to complete the sentences contained in the diagram. black hole ...
... Use words or phrases from the box to complete the sentences contained in the diagram. black hole ...
Project Description - SDSS-III
... on a consistent cosmological model that incorporates cold dark matter, a baryon-to-dark-matter ratio ∼1:6, flat space, and primordial fluctuations with the statistical properties predicted by inflation. This model requires one very surprising ingredient, “dark energy,” which drives accelerating expa ...
... on a consistent cosmological model that incorporates cold dark matter, a baryon-to-dark-matter ratio ∼1:6, flat space, and primordial fluctuations with the statistical properties predicted by inflation. This model requires one very surprising ingredient, “dark energy,” which drives accelerating expa ...
The fate of black hole singularities and the parameters of the
... A theory that asks that only one member of an (ill-defined, and possibly infinite) ensemble exist with a particular property can have no predictive power, because it is possible that a member with any set of logically possible properties exist in such an ensemble7 The theory presented here makes cer ...
... A theory that asks that only one member of an (ill-defined, and possibly infinite) ensemble exist with a particular property can have no predictive power, because it is possible that a member with any set of logically possible properties exist in such an ensemble7 The theory presented here makes cer ...
Using Parallax to Measure the Distance of Stars
... One of the most difficult problems in astronomy is determining the distances to objects in the sky. There are four basic methods of determining distances: radar, parallax, standard candles, and the Hubble Law. Each of these methods is most useful at certain distances, with radar being useful nearby ...
... One of the most difficult problems in astronomy is determining the distances to objects in the sky. There are four basic methods of determining distances: radar, parallax, standard candles, and the Hubble Law. Each of these methods is most useful at certain distances, with radar being useful nearby ...
Determination of accurate stellar radial
... convection (Dravins & Nordlund 1990). On the contrary, empirical determinations of such shifts might be a powerful diagnostic for the study of dynamical phenomena in stellar atmospheres (Dravins 1999). This requires that the true velocity can be established by other means, which was previously possi ...
... convection (Dravins & Nordlund 1990). On the contrary, empirical determinations of such shifts might be a powerful diagnostic for the study of dynamical phenomena in stellar atmospheres (Dravins 1999). This requires that the true velocity can be established by other means, which was previously possi ...
Sample pages 1 PDF
... nuclear physics is occurring. Therefore, most AGB stars are classified as M, R, N or S, designations that have mostly been replaced by a collective term C, or “carbon stars.” Such stars have an abundance of carbon or oxygen in their photospheres, as there is an exchange of material between the core a ...
... nuclear physics is occurring. Therefore, most AGB stars are classified as M, R, N or S, designations that have mostly been replaced by a collective term C, or “carbon stars.” Such stars have an abundance of carbon or oxygen in their photospheres, as there is an exchange of material between the core a ...
The Be/X-ray transient V0332153: evidence for a tilt between the
... binaries can present very different states of X-ray activity (Stella, White & Rosner 1986). In quiescence, they display persistent low-luminosity (Lx & 1036 erg s21 ) X-ray emission or no detectable emission at all. Occasionally, they show series of periodical (Type I) X-ray outbursts (Lx < 1036 2 1 ...
... binaries can present very different states of X-ray activity (Stella, White & Rosner 1986). In quiescence, they display persistent low-luminosity (Lx & 1036 erg s21 ) X-ray emission or no detectable emission at all. Occasionally, they show series of periodical (Type I) X-ray outbursts (Lx < 1036 2 1 ...
the next decade - Lowell Observatory
... Today “Mount Wilson S” is universally recognized as a standard measure of stellar activity, but it contains a color term (due to its dependence on nearby continua) that render it unsuitable for direct physical comparison of stars of different temperature, or for interpretation in the context of abso ...
... Today “Mount Wilson S” is universally recognized as a standard measure of stellar activity, but it contains a color term (due to its dependence on nearby continua) that render it unsuitable for direct physical comparison of stars of different temperature, or for interpretation in the context of abso ...
Stellar kinematics
Stellar kinematics is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects. The motion of a star relative to the Sun can provide useful information about the origin and age of a star, as well as the structure and evolution of the surrounding part of the Milky Way.In astronomy, it is widely accepted that most stars are born within molecular clouds known as stellar nurseries. The stars formed within such a cloud compose open clusters containing dozens to thousands of members. These clusters dissociate over time. Stars that separate themselves from the cluster's core are designated as members of the cluster's stellar association. If the remnant later drifts through the Milky Way as a coherent assemblage, then it is termed a moving group.