Anna Frebel nucleosynthesis, stars + chemical evolution
... Most likely production site: SNe II => pre-enrichment Chemical “fingerprint” of previous nucleosynthesis event (only “visible” in the oldest stars because of low metallicity) ~5% of metal-poor stars with [Fe/H] < 2.5 (Barklem et al. 05) Only 15-20 stars known so ...
... Most likely production site: SNe II => pre-enrichment Chemical “fingerprint” of previous nucleosynthesis event (only “visible” in the oldest stars because of low metallicity) ~5% of metal-poor stars with [Fe/H] < 2.5 (Barklem et al. 05) Only 15-20 stars known so ...
Binary Stars/Star Clusters
... Assumption: all stars of a given cluster formed from same Nebula ∴ All stars of a single cluster are (1) the same distance from Earth & (2) the same age ...
... Assumption: all stars of a given cluster formed from same Nebula ∴ All stars of a single cluster are (1) the same distance from Earth & (2) the same age ...
Document
... does now and hasn’t changed. The trouble is that the night sky would be completely lit up because of the billions of stars, but it’s not, so… The “Big Bang” theory This theory states that the universe started off with an explosion and everything has been moving away ever since. There are two main pi ...
... does now and hasn’t changed. The trouble is that the night sky would be completely lit up because of the billions of stars, but it’s not, so… The “Big Bang” theory This theory states that the universe started off with an explosion and everything has been moving away ever since. There are two main pi ...
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... • The thin disk: stars formed out of the thin gas disk, it gets gradually puffed up (thicker) due to dynamical effects • The thick disk: it could be a thin disk that was dynamically heated by minor mergers with other galaxies • The bulge: the original, self-enriched stellar population that formed ...
... • The thin disk: stars formed out of the thin gas disk, it gets gradually puffed up (thicker) due to dynamical effects • The thick disk: it could be a thin disk that was dynamically heated by minor mergers with other galaxies • The bulge: the original, self-enriched stellar population that formed ...
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 ...
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. ...
Week 5 - OSU Astronomy
... Nuclear thermostat • Nuclear reactions are very sensitive to temperature – small increase in temperature produces large increase in reaction rates and energy production – this is good! It provides stability to the star – If core temperature too low, gravity forces it to contract, temperature goes up ...
... Nuclear thermostat • Nuclear reactions are very sensitive to temperature – small increase in temperature produces large increase in reaction rates and energy production – this is good! It provides stability to the star – If core temperature too low, gravity forces it to contract, temperature goes up ...
Lecture 29: Ellipticals and Irregulars
... Integrated light/spectra Emission lines, particularly from neutral hydrogen and molecular gas. ...
... Integrated light/spectra Emission lines, particularly from neutral hydrogen and molecular gas. ...
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 ...
... 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 ...
Exoplanets: The search for planets beyond our
... team recently announced the discovery of a planet in a nearby Sun-like system. The planet had a mass of 10 to 12 Earth masses and a period of about 350 Earth days. The telltale RV signal is about 1.6 m/s. However, to find true “Earths” in a habitable zone would require extracting a signal of only 0. ...
... team recently announced the discovery of a planet in a nearby Sun-like system. The planet had a mass of 10 to 12 Earth masses and a period of about 350 Earth days. The telltale RV signal is about 1.6 m/s. However, to find true “Earths” in a habitable zone would require extracting a signal of only 0. ...
The Milky Way II AST 112
... Star-Gas-Star Cycle • Matter in the Milky Way goes in cycles – Matter is taken out of the ISM when stars are born – Matter is altered and returned to the ISM throughout the star’s life and when it dies – This is called the Star-Gas-Star Cycle ...
... Star-Gas-Star Cycle • Matter in the Milky Way goes in cycles – Matter is taken out of the ISM when stars are born – Matter is altered and returned to the ISM throughout the star’s life and when it dies – This is called the Star-Gas-Star Cycle ...
Document
... around a white dwarf • Type 1a Supernova: collapse and explosion of a white dwarf that has accreted enough mass to go overcome electron degeneracy ...
... around a white dwarf • Type 1a Supernova: collapse and explosion of a white dwarf that has accreted enough mass to go overcome electron degeneracy ...
P1 The Earth in the Universe
... does now and hasn’t changed. The trouble is that the night sky would be completely lit up because of the billions of stars, but it’s not, so… The “Big Bang” theory This theory states that the universe started off with an explosion and everything has been moving away ever since. There are two main pi ...
... does now and hasn’t changed. The trouble is that the night sky would be completely lit up because of the billions of stars, but it’s not, so… The “Big Bang” theory This theory states that the universe started off with an explosion and everything has been moving away ever since. There are two main pi ...
A minimum column density of 1gcm(
... them both the only type of young star we can observe in distant galaxies and the dominant energy sources in the Universe today. They form rarely because efficient radiative cooling keeps most star-forming gas clouds close to isothermal as they collapse, and this favours fragmentation into stars of o ...
... them both the only type of young star we can observe in distant galaxies and the dominant energy sources in the Universe today. They form rarely because efficient radiative cooling keeps most star-forming gas clouds close to isothermal as they collapse, and this favours fragmentation into stars of o ...
Document
... Two GR correction terms (Rg/R): Yu.L.Vartanian (1972), Diss. For nonrotating stars. ...
... Two GR correction terms (Rg/R): Yu.L.Vartanian (1972), Diss. For nonrotating stars. ...
fact sheet about the Andromeda galaxy
... the chemical composition of stars in Andromeda, remarkable though that sounds. You can literally take the light of individual stars, spread them out into the colours of the rainbow, much more finely than a typical rainbow, into thousands of colours and from that you can measure the doppler shift of ...
... the chemical composition of stars in Andromeda, remarkable though that sounds. You can literally take the light of individual stars, spread them out into the colours of the rainbow, much more finely than a typical rainbow, into thousands of colours and from that you can measure the doppler shift of ...
Distances
... its effects must be independently determined, for example by use of reddening-free indicies (BM98, Ch. 3.7.1), before reliable results can be obtained. Further uncertainties arise if the clusters compared have different metallicities or ages. Nonetheless, the technique of main sequence fitting, cali ...
... its effects must be independently determined, for example by use of reddening-free indicies (BM98, Ch. 3.7.1), before reliable results can be obtained. Further uncertainties arise if the clusters compared have different metallicities or ages. Nonetheless, the technique of main sequence fitting, cali ...
ppt - University of Arizona
... function of z is much better known. • Stellar mass assembly rate can be characterized for the first time. • Spitzer is showing us that galaxies at z~7 formed stars Egami et al. 2005 as much as 200-400 million Imagine such a galaxy at 2x years earlier (around z~10) the redshift => z~14 Epoch of fir ...
... function of z is much better known. • Stellar mass assembly rate can be characterized for the first time. • Spitzer is showing us that galaxies at z~7 formed stars Egami et al. 2005 as much as 200-400 million Imagine such a galaxy at 2x years earlier (around z~10) the redshift => z~14 Epoch of fir ...
9.1 Introduction 9.2 Static Models
... Irrespectively of whether they are formulated in Eulerian or Lagrangian coordinates, the four independent equations of stellar structure cannot be solve analytically without making some simplifying assumptions. The reasons are that: (i) the equations are very non linear. The energy generation rate E ...
... Irrespectively of whether they are formulated in Eulerian or Lagrangian coordinates, the four independent equations of stellar structure cannot be solve analytically without making some simplifying assumptions. The reasons are that: (i) the equations are very non linear. The energy generation rate E ...
Clase-06_Star_Formation - Departamento de Astronomía
... collapse of the core temperature continues rising and H becomes ionized (HII) free e- pressure starts to balance the collapse that eventually halts in the core convective proto-star reachs the Hayashi limit in the CM diagram and enter the hydrostatic equilibrium regime (becoming a T-Tauri star ...
... collapse of the core temperature continues rising and H becomes ionized (HII) free e- pressure starts to balance the collapse that eventually halts in the core convective proto-star reachs the Hayashi limit in the CM diagram and enter the hydrostatic equilibrium regime (becoming a T-Tauri star ...
Stars with T eff
... In some cases - as in Maraston (2005) - the AGB contribution to both the bolometric and near-IR light of a stellar population, is much larger (a factor of 2 or more…) than in other models… see the talks by Bruzual and Conroy ...
... In some cases - as in Maraston (2005) - the AGB contribution to both the bolometric and near-IR light of a stellar population, is much larger (a factor of 2 or more…) than in other models… see the talks by Bruzual and Conroy ...
binary stars
... The angular separations and orbital paths are only apparent because in general the orbit is inclined to the plane of the sky, so we see the orbit in projection ...
... The angular separations and orbital paths are only apparent because in general the orbit is inclined to the plane of the sky, so we see the orbit in projection ...
The Sun and the Stars
... The angular separations and orbital paths are only apparent because in general the orbit is inclined to the plane of the sky, so we see the orbit in projection ...
... The angular separations and orbital paths are only apparent because in general the orbit is inclined to the plane of the sky, so we see the orbit in projection ...
Stellar Winds and Hydrodynamic Atmospheres of Stars
... If ionization of the atoms with subsequent recombination dominates, then the population of the upper level is controlled from electron transitions cascading from above ...
... If ionization of the atoms with subsequent recombination dominates, then the population of the upper level is controlled from electron transitions cascading from above ...
Spectroscopy - Jefferson Lab
... • Spectroscopy- the study of the light from an object. • Spectrometer- an instrument which spreads out light making a spectra. • Spectra- range of electromagnetic energy separated by wavelength. ...
... • Spectroscopy- the study of the light from an object. • Spectrometer- an instrument which spreads out light making a spectra. • Spectra- range of electromagnetic energy separated by wavelength. ...
Planetary nebula
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.