Is $^ 6$ Li in metal-poor halo stars produced in situ by solar
... Li abundance measured in that star. However, Lemoine et al. (1997) have questioned this result on the basis of the 6 Li production efficiency: assuming the flaring activity of the contemporary Sun for one billion years, they found the amount of flareproduced 6 Li to be negligible as compared with the ...
... Li abundance measured in that star. However, Lemoine et al. (1997) have questioned this result on the basis of the 6 Li production efficiency: assuming the flaring activity of the contemporary Sun for one billion years, they found the amount of flareproduced 6 Li to be negligible as compared with the ...
Chemical Signatures in Dwarf Galaxies
... How these different types of galaxies are related to one another raises an interesting series of questions. Are dwarf gal axies related to protogalactic fragments, the low mass systems that formed in a L Cold Dark Matter (LCDM) Universe that later merged to build up the large spirals that we see to ...
... How these different types of galaxies are related to one another raises an interesting series of questions. Are dwarf gal axies related to protogalactic fragments, the low mass systems that formed in a L Cold Dark Matter (LCDM) Universe that later merged to build up the large spirals that we see to ...
Article PDF - IOPscience
... and therefore the observed abundances are averaged over the halo and disk gas, if not over the whole Galactic content. At early times, in the collapse scenario, it is reasonable to expect that there may be enough gas at low metallicity still present, thus reducing the observed integrated [FeyH]. Thi ...
... and therefore the observed abundances are averaged over the halo and disk gas, if not over the whole Galactic content. At early times, in the collapse scenario, it is reasonable to expect that there may be enough gas at low metallicity still present, thus reducing the observed integrated [FeyH]. Thi ...
The Sun's Crowded Delivery Room July 6, 2007
... Short-lived isotopes no longer actually exist in meteorites, except for a few produced by cosmic ray interactions. They formed in other stars (and perhaps close to the Sun in our Solar System), were incorporated into solids such as meteorite parent bodies and the planetesimals that accreted to form ...
... Short-lived isotopes no longer actually exist in meteorites, except for a few produced by cosmic ray interactions. They formed in other stars (and perhaps close to the Sun in our Solar System), were incorporated into solids such as meteorite parent bodies and the planetesimals that accreted to form ...
astronomy - Scioly.org
... -At 10m kelvin, stars will begin hydrogen fusion via the proton-proton chain reaction. Hydrogen is fused first into deuterium and then to helium. P-P chain is primarily found in the lower main sequence. -Stars with masses slightly over 1 solar mass (~>1.5) will generate a large portion of their ener ...
... -At 10m kelvin, stars will begin hydrogen fusion via the proton-proton chain reaction. Hydrogen is fused first into deuterium and then to helium. P-P chain is primarily found in the lower main sequence. -Stars with masses slightly over 1 solar mass (~>1.5) will generate a large portion of their ener ...
Basics about stars
... the pull of gravity. The Chandrasekhar limit prohibits WD‘s more massive than 1.44M • Neutron stars : Stars with initially up to 25M end their life as Neutron stars. A supernova Type II is associated with the formation of a neutron star • Black hole : For more massive stars even the neutron degene ...
... the pull of gravity. The Chandrasekhar limit prohibits WD‘s more massive than 1.44M • Neutron stars : Stars with initially up to 25M end their life as Neutron stars. A supernova Type II is associated with the formation of a neutron star • Black hole : For more massive stars even the neutron degene ...
Lecture 12- Stars: Distances and Magnitudes
... • Apparent magnitude is the brightness of an object as it appears to you • System due to Hipparchos (2nd century BC) • Nowadays system made more precise • Magnitude changes are “logarithmic”, each magnitude means factor of 2.512 in brightness • Brightness in magnitudes in Table 16.1 • Apparent magni ...
... • Apparent magnitude is the brightness of an object as it appears to you • System due to Hipparchos (2nd century BC) • Nowadays system made more precise • Magnitude changes are “logarithmic”, each magnitude means factor of 2.512 in brightness • Brightness in magnitudes in Table 16.1 • Apparent magni ...
Draft A101 Slide Set #1 - Astronomical Society of the Pacific
... The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a partnership of NASA and the German Aerospace Center (DLR), consisting of an extensively modified Boeing 747SP aircraft carrying a reflecting telescope with an effective diameter of 2.5 meters (100 inches). Based at NASA's Armstrong Fl ...
... The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a partnership of NASA and the German Aerospace Center (DLR), consisting of an extensively modified Boeing 747SP aircraft carrying a reflecting telescope with an effective diameter of 2.5 meters (100 inches). Based at NASA's Armstrong Fl ...
The Properties of Stars
... It is useful to measure the magnitude of a star through colored filters. One standard set (called the UBV system) consists of filters that transmit a narrow range around 350 nm (ultraviolet), 435 nm (blue), and 555nm (green = visual). The apparent magnitudes measured through these filters are denote ...
... It is useful to measure the magnitude of a star through colored filters. One standard set (called the UBV system) consists of filters that transmit a narrow range around 350 nm (ultraviolet), 435 nm (blue), and 555nm (green = visual). The apparent magnitudes measured through these filters are denote ...
9.1 Introduction 9.2 Static Models
... not always the case in astrophysics. For example, the interstellar medium in galaxies is a very complex environment and we are still a long way from being able to satisfactorily model it in our computers. On the other hand, the evolution of the whole Universe can be described with the Friedmann equa ...
... not always the case in astrophysics. For example, the interstellar medium in galaxies is a very complex environment and we are still a long way from being able to satisfactorily model it in our computers. On the other hand, the evolution of the whole Universe can be described with the Friedmann equa ...
7/3 Some stars were found in regions above the main sequence
... Giant Stars — about the same mass as main sequence stars but much larger — small densities — range form a hundredth to a tenth of the density of water. Supergiant Stars — still no more massive than main sequence stars but much much larger — 0.00000001 to 0.001 times the density of water. White Dwarf ...
... Giant Stars — about the same mass as main sequence stars but much larger — small densities — range form a hundredth to a tenth of the density of water. Supergiant Stars — still no more massive than main sequence stars but much much larger — 0.00000001 to 0.001 times the density of water. White Dwarf ...
AS 701 - INTRODUCTION TO ASTROPHYSICS COURSE OVERVIEW - FALL 2013
... and gravitational physics, properties of stars, stellar structure, stellar evolution, dynamics of binary stars systems and star clusters, types of galaxies, galactic structure and dynamics, active galaxies and some cosmological topics. COURSE STRUCTURE AND PHILOSOPHY: The course is intended to provi ...
... and gravitational physics, properties of stars, stellar structure, stellar evolution, dynamics of binary stars systems and star clusters, types of galaxies, galactic structure and dynamics, active galaxies and some cosmological topics. COURSE STRUCTURE AND PHILOSOPHY: The course is intended to provi ...
The Properties of Stars
... Giant stars are larger and less dense than main sequence stars, so their absorption lines are narrower than those of main sequence stars. The spectra shown above illustrate this effect. Notice that the absorption lines in the spectra of the giant (13 Mono ) and supergiant (HR 1040) stars are narrowe ...
... Giant stars are larger and less dense than main sequence stars, so their absorption lines are narrower than those of main sequence stars. The spectra shown above illustrate this effect. Notice that the absorption lines in the spectra of the giant (13 Mono ) and supergiant (HR 1040) stars are narrowe ...
P1a_Revision_lesson
... as a fuel. During its main sequence a star will release energy by combining hydrogen and helium nuclei (light elements) into _________ elements. Any element in space that is heavier than helium is thought to have been made in a star. Words – heavier, balanced, hydrogen, nuclear, temperatures ...
... as a fuel. During its main sequence a star will release energy by combining hydrogen and helium nuclei (light elements) into _________ elements. Any element in space that is heavier than helium is thought to have been made in a star. Words – heavier, balanced, hydrogen, nuclear, temperatures ...
Mass loss in semi-detached binaries
... (c) Tracks (small dashed curves) of pre-Main-Sequence contracting single stars of various masses (marked on the curves) according to Iben (1965). (d) Tracks (long-dashed curves) of post-Main-Sequence single stars of various masses (marked on the curves) due to Iben (1964). (e) Track of a rapidly mas ...
... (c) Tracks (small dashed curves) of pre-Main-Sequence contracting single stars of various masses (marked on the curves) according to Iben (1965). (d) Tracks (long-dashed curves) of post-Main-Sequence single stars of various masses (marked on the curves) due to Iben (1964). (e) Track of a rapidly mas ...
Document
... • The cosmic timeline: – Observations go back to t~3 minutes – Reasonably firm physics back to tt~10 ...
... • The cosmic timeline: – Observations go back to t~3 minutes – Reasonably firm physics back to tt~10 ...
double shell–burning
... Star Clusters and Stellar Lives • Our knowledge of the life stories of stars comes from comparing mathematical models of stars with observations. • Star clusters are particularly useful because they contain stars of different mass that were born about the same time. © 2010 Pearson Education, Inc. ...
... Star Clusters and Stellar Lives • Our knowledge of the life stories of stars comes from comparing mathematical models of stars with observations. • Star clusters are particularly useful because they contain stars of different mass that were born about the same time. © 2010 Pearson Education, Inc. ...
Chemical tagging of three distinct populations of red giants in the
... The abundances of aluminium were derived from GIRAFFE spectra (obtained with FLAMES, Pasquini et al. 2002, mounted at the ESO VLT-UT2 telescope) with the high resolution grating HR21. This set-up is centred at 8757 Å and the spectral resolution is R=17,300 at the center of spectra. The pointing was ...
... The abundances of aluminium were derived from GIRAFFE spectra (obtained with FLAMES, Pasquini et al. 2002, mounted at the ESO VLT-UT2 telescope) with the high resolution grating HR21. This set-up is centred at 8757 Å and the spectral resolution is R=17,300 at the center of spectra. The pointing was ...
Linking Asteroids and Meteorites through Reflectance
... flattened spheroid • This is a high density region where red stars predominate, which are very old and about 10 billion years old • There is growing evidence for a very massive black hole at its center ...
... flattened spheroid • This is a high density region where red stars predominate, which are very old and about 10 billion years old • There is growing evidence for a very massive black hole at its center ...
An automated 2 epoch Proper Motion search of UKIDSS and VISTA
... finding very cold brown dwarfs. Objects too faint for normal multiband colour selection, or those with unusual colours (e.g. recent WISE 300 K object). brown dwarf companions to stars. These are benchmark objects with known age, metallicity and Hipparcos distance that can be used to test model atmos ...
... finding very cold brown dwarfs. Objects too faint for normal multiband colour selection, or those with unusual colours (e.g. recent WISE 300 K object). brown dwarf companions to stars. These are benchmark objects with known age, metallicity and Hipparcos distance that can be used to test model atmos ...
Massive stars as thermonuclear reactors and their explosions
... universe resulting from the Big Bang, contains many more photons per particle of matter with mass, e.g. protons and neutrons. Because of the high entropy as the universe expanded, there was time to manufacture elements only upto helium and the major products of cosmic nucleosynthesis remained the li ...
... universe resulting from the Big Bang, contains many more photons per particle of matter with mass, e.g. protons and neutrons. Because of the high entropy as the universe expanded, there was time to manufacture elements only upto helium and the major products of cosmic nucleosynthesis remained the li ...
Examples of ERC Starting Grant Projects 2015
... One of the least understood aspects of the chemical evolution of the cosmos is the making of elements heavier than iron. Professor Almudena Arcones Segovia from the Technische Universitat Darmstadt is set to change this. There are two favoured astrophysical production sites of heavy elements: neutri ...
... One of the least understood aspects of the chemical evolution of the cosmos is the making of elements heavier than iron. Professor Almudena Arcones Segovia from the Technische Universitat Darmstadt is set to change this. There are two favoured astrophysical production sites of heavy elements: neutri ...
The Big Bang and Stellar Evolution
... or a planet, or anything else. Since both hydrogen and helium are gases, they are good at spreading out, but not at clumping together. 2 - Careful analysis has revealed that there is not enough matter in gas clouds to produce stars. 3 - There would not be enough time for the gas to reach the current ...
... or a planet, or anything else. Since both hydrogen and helium are gases, they are good at spreading out, but not at clumping together. 2 - Careful analysis has revealed that there is not enough matter in gas clouds to produce stars. 3 - There would not be enough time for the gas to reach the current ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.