Isotopes Tell Origin and Operation of the Sun
... significance of lightweight neon in the solar wind could not be deciphered in 1969, when isotopic anomalies from stellar nuclear reactions and mass fractionation were not resolved, decay products of only two extinct nuclides had been found in meteorites [4, 5], and it was still widely believed that ...
... significance of lightweight neon in the solar wind could not be deciphered in 1969, when isotopic anomalies from stellar nuclear reactions and mass fractionation were not resolved, decay products of only two extinct nuclides had been found in meteorites [4, 5], and it was still widely believed that ...
Carbon, nitrogen, oxygen and lithium abundances of six
... chemical evolution. A mean deficiency of the carbon-to-iron ratio of [C/Fe] ≈–0.3 dex and a nitrogen-to-iron ratio [N/Fe] ≈+0.22 dex might imply a mixing signature, which is confirmed by the low 12 C/13 C ratio measured in three stars. In terms of chemical evolution, carbon plus nitrogen abundances ...
... chemical evolution. A mean deficiency of the carbon-to-iron ratio of [C/Fe] ≈–0.3 dex and a nitrogen-to-iron ratio [N/Fe] ≈+0.22 dex might imply a mixing signature, which is confirmed by the low 12 C/13 C ratio measured in three stars. In terms of chemical evolution, carbon plus nitrogen abundances ...
The Life Cycles of Stars
... various elements are formed within the core of the star, with the heaviest sustainable material being iron, when a massive star forms an iron core. However, any elements heavier and denser than iron cannot be produced internally by stellar bodies (stars). The only way to create such substances is th ...
... various elements are formed within the core of the star, with the heaviest sustainable material being iron, when a massive star forms an iron core. However, any elements heavier and denser than iron cannot be produced internally by stellar bodies (stars). The only way to create such substances is th ...
L and T Dwarfs - Indiana University
... Free-free opacities – Thomson and Rayleigh scattering In metal-poor low mass stars, pressure induced absorption of H2H2 is important in the IR (longer than 1 micron) H2 molecules have allowed transitions only at electric quadrupole and higher order moments, so H2 itself is not significant Also signi ...
... Free-free opacities – Thomson and Rayleigh scattering In metal-poor low mass stars, pressure induced absorption of H2H2 is important in the IR (longer than 1 micron) H2 molecules have allowed transitions only at electric quadrupole and higher order moments, so H2 itself is not significant Also signi ...
Resolved SPs : simulations
... •The model CMDs may NOT contain the solution •The method requires a lot of computing: Does this really improve the solution? (apart from giving a quantitative estimate of the quality of the fit) Dolphin: “ The solution with RGB+HB was extremely successful, measuring …the SFH with nearly the same acc ...
... •The model CMDs may NOT contain the solution •The method requires a lot of computing: Does this really improve the solution? (apart from giving a quantitative estimate of the quality of the fit) Dolphin: “ The solution with RGB+HB was extremely successful, measuring …the SFH with nearly the same acc ...
Answer Key: Big Bang Balloon Analysis Questions
... were devising an experiment to look for this predicted, but before they could carry it out, this radiation was actually found by accident! Right here in New Jersey, a couple of engineers were using a microwave antenna in order to try to detect emissions from gas in the Milky Way Galaxy. They encount ...
... were devising an experiment to look for this predicted, but before they could carry it out, this radiation was actually found by accident! Right here in New Jersey, a couple of engineers were using a microwave antenna in order to try to detect emissions from gas in the Milky Way Galaxy. They encount ...
Abundance Anomalies In Tidal Disruption Events
... find that extreme hydrogen to helium line ratios are achievable at Solar metallicity using broad line widths and radiation transfer models better suited to high optical depths than CLOUDY. All these calculations have assumed that the debris has Solar composition. This may be true at birth on the zer ...
... find that extreme hydrogen to helium line ratios are achievable at Solar metallicity using broad line widths and radiation transfer models better suited to high optical depths than CLOUDY. All these calculations have assumed that the debris has Solar composition. This may be true at birth on the zer ...
Life Cycle of stars
... comes near it. Black holes are so massive that their own gravity consumes everything in its vicinity such as stars, planets, and even light cannot escape. Black holes cannot be seen thus making them not visible. Scientist can only observe what's around the black holes. Black holes can however be de ...
... comes near it. Black holes are so massive that their own gravity consumes everything in its vicinity such as stars, planets, and even light cannot escape. Black holes cannot be seen thus making them not visible. Scientist can only observe what's around the black holes. Black holes can however be de ...
X-ray studies of star and planet formation Eric Feigelson
... turbulent. Protoplanets interact with the gas in complex ways (e.g. migration). ...
... turbulent. Protoplanets interact with the gas in complex ways (e.g. migration). ...
Maximum Mass Limit of Stars on the Main Sequence
... Competitive accretion is also a viable method for creation of massive stars. Bonnell presents 3D simulations of stellar mass growth by competitive accretion in small young clusters. In this method, growth is promoted by the size and composition of the stars accretion domain. As mass increases, the ...
... Competitive accretion is also a viable method for creation of massive stars. Bonnell presents 3D simulations of stellar mass growth by competitive accretion in small young clusters. In this method, growth is promoted by the size and composition of the stars accretion domain. As mass increases, the ...
Neutron Stars
... C: The total mass of the two pulsars must be more than 10 solar masses. D: Each of the pulsars was produced by a massive star that exploded in a Supernova event. ...
... C: The total mass of the two pulsars must be more than 10 solar masses. D: Each of the pulsars was produced by a massive star that exploded in a Supernova event. ...
Section I - General Information Proposal Title: Mass and Radius of a
... for accurate pulse-phase folding of the NICER data across its 18-month mission duration, enabling the essential X-ray pulse profile modeling required to infer the stellar mass-to-radius ratio. Outreach Abstract: An outstanding question in nuclear physics is how the matter that makes up the nuclei of ...
... for accurate pulse-phase folding of the NICER data across its 18-month mission duration, enabling the essential X-ray pulse profile modeling required to infer the stellar mass-to-radius ratio. Outreach Abstract: An outstanding question in nuclear physics is how the matter that makes up the nuclei of ...
PROBLEM SET #6 AST142 Due in class Tuesday Mar 17, 2015 First
... 1. Initial mass function Star formation regions contain both low and high mass stars but they are not born with equal probability. The mass distribution at birth is described with a function called the initial mass function (IMF). Consider the initial mass function with number of stars in a mass bin ...
... 1. Initial mass function Star formation regions contain both low and high mass stars but they are not born with equal probability. The mass distribution at birth is described with a function called the initial mass function (IMF). Consider the initial mass function with number of stars in a mass bin ...
S-process in extremely metal-poor, low-mass stars
... the beginning of the thermally pulsating asymptotic giant branch (TP-AGB) phase. Similar to the occurrence of the PIE during the core He-flash, proton-rich material is dragged down into the He-burning zone during the development of a thermal runaway in the He-shell. After the ensuing dredge-up event ...
... the beginning of the thermally pulsating asymptotic giant branch (TP-AGB) phase. Similar to the occurrence of the PIE during the core He-flash, proton-rich material is dragged down into the He-burning zone during the development of a thermal runaway in the He-shell. After the ensuing dredge-up event ...
Globular Clusters - University of Dayton
... * The homogeneity of the stars in these clusters (note the similar colours of all the stars in the image of NGC104 above) indicates that they have similar chemical compositions and similar ages. This makes them the simplest systems to use to test theoretical models of star formation and evolution. * ...
... * The homogeneity of the stars in these clusters (note the similar colours of all the stars in the image of NGC104 above) indicates that they have similar chemical compositions and similar ages. This makes them the simplest systems to use to test theoretical models of star formation and evolution. * ...
and mass loss
... • In normal circumstances n p + e + ne on a time scale of 15 min • Electrons and neutrinos have a combined energy of 1.3 Mev (the mass-energy difference between n and p) • When neutrons decay, electrons with energies up to 1.3 Mev are produced it follows that neutrons cannot decay if the electro ...
... • In normal circumstances n p + e + ne on a time scale of 15 min • Electrons and neutrinos have a combined energy of 1.3 Mev (the mass-energy difference between n and p) • When neutrons decay, electrons with energies up to 1.3 Mev are produced it follows that neutrons cannot decay if the electro ...
Emission and reflection nebula are two types of star forming
... spectrometry. Through photographing specific nebula using visible light and Hydrogen Alpha filters, calibrating and processing the images[omit for abstract], and analyzing their light emission graphs[weber calls these “junk words”], differences between emission and reflection nebula are analyzed.[Th ...
... spectrometry. Through photographing specific nebula using visible light and Hydrogen Alpha filters, calibrating and processing the images[omit for abstract], and analyzing their light emission graphs[weber calls these “junk words”], differences between emission and reflection nebula are analyzed.[Th ...
Chapter12 (with interactive links)
... in the expanding outer layers, causing the planetary nebula that we can observe. Planetary nebulae do not last forever – eventually the gas disperses. ...
... in the expanding outer layers, causing the planetary nebula that we can observe. Planetary nebulae do not last forever – eventually the gas disperses. ...
26.3 Life Cycles of Stars
... Small nebulas produce small, cool stars that are long-lived. A star can have a mass as low as a tenth of the sun’s mass. The gravitational force in such low-mass stars is just strong enough to create a small core where nuclear fusion takes place. This lower energy production results in red stars, th ...
... Small nebulas produce small, cool stars that are long-lived. A star can have a mass as low as a tenth of the sun’s mass. The gravitational force in such low-mass stars is just strong enough to create a small core where nuclear fusion takes place. This lower energy production results in red stars, th ...
dm - The Institute of Mathematical Sciences
... we do not know what it is. In fact we know more about what it is not. In principle they could be dead stars which have stopped emitting light or any other form of radiation, known as white dwarfs. They could be brown stars, stars which failed to ignite in the first place. There are many millions or ...
... we do not know what it is. In fact we know more about what it is not. In principle they could be dead stars which have stopped emitting light or any other form of radiation, known as white dwarfs. They could be brown stars, stars which failed to ignite in the first place. There are many millions or ...
Dr.Sinha - Indico
... Arrow of Time Emission of cosmic background radiation Dark ages First stars First supernovae and black holes ...
... Arrow of Time Emission of cosmic background radiation Dark ages First stars First supernovae and black holes ...
Section 7 The Big Bang Theory
... Today, CMB radiation is very cold, only 2.725 K above absolute zero and this cooling of the photon means its frequency has reduced until the radiation shines primarily in the microwave portion of the electromagnetic spectrum and is invisible to the naked eye. However, it can be detected everywhere w ...
... Today, CMB radiation is very cold, only 2.725 K above absolute zero and this cooling of the photon means its frequency has reduced until the radiation shines primarily in the microwave portion of the electromagnetic spectrum and is invisible to the naked eye. However, it can be detected everywhere w ...
Chapter 18 - Stars - University of New Mexico
... • Some consists of dim objects (brown dwarfs, white dwarfs, neutron stars, black holes, i.e. “MACHOs”), but not all. Limits on this from “gravitational microlensing” in the halo. Result: few to 20% of dark matter at most. ...
... • Some consists of dim objects (brown dwarfs, white dwarfs, neutron stars, black holes, i.e. “MACHOs”), but not all. Limits on this from “gravitational microlensing” in the halo. Result: few to 20% of dark matter at most. ...
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.