Doomed, Insignificant, and Ignorant
... orbital rotation speed disagrees with observed rotation speed Also observed in other near by galaxies. Result was viewed with great skepticism during ‘70’s and ‘80’s ...
... orbital rotation speed disagrees with observed rotation speed Also observed in other near by galaxies. Result was viewed with great skepticism during ‘70’s and ‘80’s ...
Chapter 25.2 - Planet Earth
... longer has enough pressure to support itself against the inward force of gravity. As a result, the core begins to contract. As the core contracts, it grows hotter by converting gravitational energy into heat energy. Some of this energy is radiated outward, increasing hydrogen fusion in the star’s ou ...
... longer has enough pressure to support itself against the inward force of gravity. As a result, the core begins to contract. As the core contracts, it grows hotter by converting gravitational energy into heat energy. Some of this energy is radiated outward, increasing hydrogen fusion in the star’s ou ...
The dance of elements in space: from clouds to planets
... helium with a sparkling of lithium and beryllium. The Universe could have remained as such, a place with no chemistry and no life, were it not that a first star was born. A big star, not one as the many that surround us today, but much bigger than that. She lived little but shone as no other star to ...
... helium with a sparkling of lithium and beryllium. The Universe could have remained as such, a place with no chemistry and no life, were it not that a first star was born. A big star, not one as the many that surround us today, but much bigger than that. She lived little but shone as no other star to ...
High-mass stars in the Galactic center Quintuplet cluster
... the luminous late-type WN stars (WNL) are an interphase between O stars leaving the main-sequence and WR stars of the carbon sequence (WC), before these massive stars explode as supernova (SN). As shown in the HRD (Fig. 4) the WNL stars in the Quintuplet form a group of relatively cool but very lumi ...
... the luminous late-type WN stars (WNL) are an interphase between O stars leaving the main-sequence and WR stars of the carbon sequence (WC), before these massive stars explode as supernova (SN). As shown in the HRD (Fig. 4) the WNL stars in the Quintuplet form a group of relatively cool but very lumi ...
ASTR-1020: Astronomy II Course Lecture Notes - Faculty
... Initially, this protogalaxy had only H (90% by number) and He (10%) from the Big Bang — no metals =⇒ the so-called Population III stars, which are no longer in existence, were actually the very first stars to form in the Universe. ...
... Initially, this protogalaxy had only H (90% by number) and He (10%) from the Big Bang — no metals =⇒ the so-called Population III stars, which are no longer in existence, were actually the very first stars to form in the Universe. ...
Available online www.jsaer.com Journal of Scientific and
... A lot of research literatures have been published about stars. This section is a retrospective light of existing star literatures on their energy creation, colours and formation. Energy (light) creation by stars The most apparent astrophysical fact is that stars emit electromagnetic radiations and h ...
... A lot of research literatures have been published about stars. This section is a retrospective light of existing star literatures on their energy creation, colours and formation. Energy (light) creation by stars The most apparent astrophysical fact is that stars emit electromagnetic radiations and h ...
Lecture 21
... •In most stars there are two main partial ionisation zones. •The hydrogen partial ionisation zone is a broad region with a characteristic temperature of 1 to 1.5 × 104 K, in which the ...
... •In most stars there are two main partial ionisation zones. •The hydrogen partial ionisation zone is a broad region with a characteristic temperature of 1 to 1.5 × 104 K, in which the ...
Lecture 26 Pre-Main Sequence Evolution
... Due to Lada & Wilking (ApJ 287 610 1984), Adams, Lada & Shu (ApJ 312 788 1987) etc. Based on the fact that, when YSOs emerge as optically visible stars, they remain partially obscured. • Class I YSOs – (stage 2) Completely embedded objects have SEDs with positive spectral index in the far-IR: the yo ...
... Due to Lada & Wilking (ApJ 287 610 1984), Adams, Lada & Shu (ApJ 312 788 1987) etc. Based on the fact that, when YSOs emerge as optically visible stars, they remain partially obscured. • Class I YSOs – (stage 2) Completely embedded objects have SEDs with positive spectral index in the far-IR: the yo ...
Star Formation in the Galactic Center
... ‘old ‘ low-mass stars Artymowicz et al (1993) showed that star clusters close to quasars can be captured by the disk……Stars can then grow by accretion. Good: disk does not need to be self gravitating to work provided: There is enough stars Stars are trapped quickly ...
... ‘old ‘ low-mass stars Artymowicz et al (1993) showed that star clusters close to quasars can be captured by the disk……Stars can then grow by accretion. Good: disk does not need to be self gravitating to work provided: There is enough stars Stars are trapped quickly ...
14_MilkyWay_advanced_2014may
... •Postulates globular clusters orbit galactic core •More in direction of Sagittarius •Estimates core is 15kpc away from sun (error: its 9 kpc) ...
... •Postulates globular clusters orbit galactic core •More in direction of Sagittarius •Estimates core is 15kpc away from sun (error: its 9 kpc) ...
Acting Out the Life Cycle of Stars - University of Texas Astronomy
... so they have a summary of what they just did • you can film the entire activity (all 6 stages) from above for later review • this activity is currently written only for single stars; if you have a very large group you can do binary evolution and add in novae, SNe Ia, etc. • you can follow-up this ac ...
... so they have a summary of what they just did • you can film the entire activity (all 6 stages) from above for later review • this activity is currently written only for single stars; if you have a very large group you can do binary evolution and add in novae, SNe Ia, etc. • you can follow-up this ac ...
PowerPoint Presentation - The Origin of the Universe
... – Independently developed by James Peebles and George Gamov – They suggested that the universe started off in an extremely hot state – As the universe expands, the energy within the universe is spread over in increasing volume of space… – Thus the Universe cools down as it expands ...
... – Independently developed by James Peebles and George Gamov – They suggested that the universe started off in an extremely hot state – As the universe expands, the energy within the universe is spread over in increasing volume of space… – Thus the Universe cools down as it expands ...
Signatures of the first stars in the 21cm Emission and Absorption
... creating an HII region of ~ 107 Msun of gas, of physical radius ~ 1 kpc at z=30. Probably only one metal-free star forms per halo. • Star formation occurring after the HII region recombines and merges is probably from metal enriched gas. ...
... creating an HII region of ~ 107 Msun of gas, of physical radius ~ 1 kpc at z=30. Probably only one metal-free star forms per halo. • Star formation occurring after the HII region recombines and merges is probably from metal enriched gas. ...
Lecture 24 Early Universe - University of Maryland
... – Iron has the most stable nucleus – Fusing hydrogen to (eventually) iron releases energy (thus powers the star) – Further fusion of iron to give heavier elements requires energy to be put in… – Can only happen in the energetic environment of a supernova explosion – So, all heavier elements are crea ...
... – Iron has the most stable nucleus – Fusing hydrogen to (eventually) iron releases energy (thus powers the star) – Further fusion of iron to give heavier elements requires energy to be put in… – Can only happen in the energetic environment of a supernova explosion – So, all heavier elements are crea ...
Snímek 1
... Neutron scattering (mass distribution) larger r0. Larger volume of neutron matter is done by larger number of neutrons at nuclei (in the other case the volume of protons should be larger because Coulomb repulsion). Distribution of mass density connected with charge ρ = f(r) measured by electron sc ...
... Neutron scattering (mass distribution) larger r0. Larger volume of neutron matter is done by larger number of neutrons at nuclei (in the other case the volume of protons should be larger because Coulomb repulsion). Distribution of mass density connected with charge ρ = f(r) measured by electron sc ...
Presentazione di PowerPoint
... After the starting guesses of the centroids (FIND) and brightness (PHOTOMETRY) are measured, and the PSF model determined (PSF), the PSF is first shifted and scaled to the position and brightness of each star, and each profile is subtracted, out to the profile radius, from the original image. This ...
... After the starting guesses of the centroids (FIND) and brightness (PHOTOMETRY) are measured, and the PSF model determined (PSF), the PSF is first shifted and scaled to the position and brightness of each star, and each profile is subtracted, out to the profile radius, from the original image. This ...
COMPONENTS OF THE UNIVERSE
... communicates his ideas through an electronic device that converts the movements of muscles in his cheeks into words. Hawking argues that black holes were created at the birth of the universe and have been with us ever since. In the beginning, they may have been no larger than single protons. Today, ...
... communicates his ideas through an electronic device that converts the movements of muscles in his cheeks into words. Hawking argues that black holes were created at the birth of the universe and have been with us ever since. In the beginning, they may have been no larger than single protons. Today, ...
The Deaths of Very Massive Stars
... structure. For very degenerate cores with energetic shells at their edges, the presupernova structure resembles that of an asymptotic giant branch star - a compact core surrounded by thin burning shells and a low density envelope with little gravitational binding energy. The matter outside of the ir ...
... structure. For very degenerate cores with energetic shells at their edges, the presupernova structure resembles that of an asymptotic giant branch star - a compact core surrounded by thin burning shells and a low density envelope with little gravitational binding energy. The matter outside of the ir ...
Unresolved Stellar Populations
... age t, Φ(M )dM is the IMF (assumed to be the Salpeter IMF here). while Ml and Mu are the lower and upper limit to the mass of the stars. The choice of Ml , as long as sufficiently small, should not affect significantly the value of Fλ , whereas Mu is not an independent parameter and is the function ...
... age t, Φ(M )dM is the IMF (assumed to be the Salpeter IMF here). while Ml and Mu are the lower and upper limit to the mass of the stars. The choice of Ml , as long as sufficiently small, should not affect significantly the value of Fλ , whereas Mu is not an independent parameter and is the function ...
JeopardyCh21StarsGalaxiesUniverse
... The Hertzsprung-Russell Diagram for 1600 Stars found in the upper right-hand corner of the HR diagram are known as the ____________________ ...
... The Hertzsprung-Russell Diagram for 1600 Stars found in the upper right-hand corner of the HR diagram are known as the ____________________ ...
Chapter 21 Jeopardy
... The Hertzsprung-Russell Diagram for 1600 Stars found in the upper right-hand corner of the HR diagram are known as the ____________________ ...
... The Hertzsprung-Russell Diagram for 1600 Stars found in the upper right-hand corner of the HR diagram are known as the ____________________ ...
High-precision abundances of elements in solar twin stars: Trends
... the Sun has an unusual low ratio between refractory and volatile elements. This has led to the suggestion that the relation between abundance ratios, [X/Fe], and elemental condensation temperature, T C , can be used as a signature of the existence of terrestrial planets around a star. > 600 for 21 s ...
... the Sun has an unusual low ratio between refractory and volatile elements. This has led to the suggestion that the relation between abundance ratios, [X/Fe], and elemental condensation temperature, T C , can be used as a signature of the existence of terrestrial planets around a star. > 600 for 21 s ...
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.