Astronomy 1001/1005 Final Exam (250 points)
... spiral arms as well as gas and dust. They also have a central spheroidal bulge and are surrounded by a spheroidal halo containing globular clusters. Elliptical Galaxies are simple spheroidal collections of stars. The stars are usually very old as ellipticals are devoid of gas and dust, preventing on ...
... spiral arms as well as gas and dust. They also have a central spheroidal bulge and are surrounded by a spheroidal halo containing globular clusters. Elliptical Galaxies are simple spheroidal collections of stars. The stars are usually very old as ellipticals are devoid of gas and dust, preventing on ...
–1– 1. Convection Convection In Stars – Things We Need to
... per particle, is constant. We assume that the ionization equilibium and energy level populations are constant as well. We assume the fluid is almost incompressible. The last few of above set of assumptions is sometimes called the Bousinesq approximation. ...
... per particle, is constant. We assume that the ionization equilibium and energy level populations are constant as well. We assume the fluid is almost incompressible. The last few of above set of assumptions is sometimes called the Bousinesq approximation. ...
Lecture 5: The Gray Atmosphere
... Lecture 5: The Gray Atmosphere As an illustration of how the equation of radiative transfer can be used and of how we can begin to understand stellar atmospheres in some detail through theory, we discuss the “gray atmosphere”. This illustrates how astronomers were able to derive the basic temperatur ...
... Lecture 5: The Gray Atmosphere As an illustration of how the equation of radiative transfer can be used and of how we can begin to understand stellar atmospheres in some detail through theory, we discuss the “gray atmosphere”. This illustrates how astronomers were able to derive the basic temperatur ...
1448 Rapid Contraction of a Protostar to the Stage of Quasi
... beginning of the pre-main-sequence slow contraction. The main results of this study have also been summarized by Hayashi. 6) According to the above study, the initial stage of the opaque protostar, from which an adiabatic contraction begins, is determined mainly by the cooling effect of grains, almo ...
... beginning of the pre-main-sequence slow contraction. The main results of this study have also been summarized by Hayashi. 6) According to the above study, the initial stage of the opaque protostar, from which an adiabatic contraction begins, is determined mainly by the cooling effect of grains, almo ...
The Death of Massive Stars
... • After the helium flash, a yellow giant then expands again into a red giant. • Stars more massive than 2 solar masses do not experience a helium flash, but will simply expand through the yellow giant stage to its one and only red giant stage. ...
... • After the helium flash, a yellow giant then expands again into a red giant. • Stars more massive than 2 solar masses do not experience a helium flash, but will simply expand through the yellow giant stage to its one and only red giant stage. ...
binary stars
... In the case of the Earth-Sun system, mSun>>mEarth, and the common centre of mass is located within the stellar radius, i.e. a1>>a2 Expressing the masses in solar masses and orbital radii in AU, then P has units of years, and thus the general form of Kepler’s third law can be written: m1 m2 ...
... In the case of the Earth-Sun system, mSun>>mEarth, and the common centre of mass is located within the stellar radius, i.e. a1>>a2 Expressing the masses in solar masses and orbital radii in AU, then P has units of years, and thus the general form of Kepler’s third law can be written: m1 m2 ...
The Sun and the Stars
... In the case of the Earth-Sun system, mSun>>mEarth, and the common centre of mass is located within the stellar radius, i.e. a1>>a2 Expressing the masses in solar masses and orbital radii in AU, then P has units of years, and thus the general form of Kepler’s third law can be written: m1 m2 ...
... In the case of the Earth-Sun system, mSun>>mEarth, and the common centre of mass is located within the stellar radius, i.e. a1>>a2 Expressing the masses in solar masses and orbital radii in AU, then P has units of years, and thus the general form of Kepler’s third law can be written: m1 m2 ...
Stellar Physics
... strength for a unique temperature. Clearly this is not sufficient on its own since for all other strengths there are two possible temperatures. The solution is to add one or more graphs for other elements which increases the precision with which the temperature can be measured. This technique is som ...
... strength for a unique temperature. Clearly this is not sufficient on its own since for all other strengths there are two possible temperatures. The solution is to add one or more graphs for other elements which increases the precision with which the temperature can be measured. This technique is som ...
–1– 28. HIGH-MASS STAR FORMATION: THEORY 28.1. The Effects
... s−1 considered by Keto, this restricts the accretion rate to ṁ∗ . 3 × 10−5 M¯ yr−1 , smaller than the values he considers. (One can show that when one generalizes the Bondi accretion model to approximately include the self gravity of the gas, the accretion rate is indeed about c 3 /G.) Bonnell and ...
... s−1 considered by Keto, this restricts the accretion rate to ṁ∗ . 3 × 10−5 M¯ yr−1 , smaller than the values he considers. (One can show that when one generalizes the Bondi accretion model to approximately include the self gravity of the gas, the accretion rate is indeed about c 3 /G.) Bonnell and ...
(Relative) Distances from the HST Snapshot Database
... Canonical models predict that the HeII convective region approaches the stellar surface in the ZAHB structures at T=23.000. In addition, mass loss, which is a competing process to diffusion increases with effective temperature. As a result, radiative levitation is less and less effective in the temp ...
... Canonical models predict that the HeII convective region approaches the stellar surface in the ZAHB structures at T=23.000. In addition, mass loss, which is a competing process to diffusion increases with effective temperature. As a result, radiative levitation is less and less effective in the temp ...
powerpoint file - QUB Astrophysics Research Centre
... assumed uniform (e.g. if stars is mixed by convective processes). • Polytropic models: method of simplifying the equations. Simple relation between pressure and density (for example) is assumed valid throughout the star. Eqns of hydrostatic support and mass conservation can be solved independently o ...
... assumed uniform (e.g. if stars is mixed by convective processes). • Polytropic models: method of simplifying the equations. Simple relation between pressure and density (for example) is assumed valid throughout the star. Eqns of hydrostatic support and mass conservation can be solved independently o ...
m 1
... m1 + m2 = (42 / GP2)P3(K1+K2)3/83sin3i = P(K1+K2)3/2G sin3i (m1+ m2)P2 = (a1+ a2)3 = a13(1+ a2/a1)3 ...
... m1 + m2 = (42 / GP2)P3(K1+K2)3/83sin3i = P(K1+K2)3/2G sin3i (m1+ m2)P2 = (a1+ a2)3 = a13(1+ a2/a1)3 ...
Numerical simulations of convection in A
... (dashed line); middle left: root-mean-square of vertical velocity; middle right: decadic logarithm of root-mean-square of vertical velocity; bottom left and right: enthalpy flux (continuous line) and flux of kinetic energy (dashed line). The two small regions with negative entropy gradient indicate ...
... (dashed line); middle left: root-mean-square of vertical velocity; middle right: decadic logarithm of root-mean-square of vertical velocity; bottom left and right: enthalpy flux (continuous line) and flux of kinetic energy (dashed line). The two small regions with negative entropy gradient indicate ...
1 - Stars: Introduction
... 1.5 - Distance to stars: Bolometric magnitude Mbol Magnitudes are measured in some wavelength band. To compare with theory it is more useful to determine bolometric magnitude – defined as absolute magnitude that would be measured by a bolometer* sensi)ve to all wavelengths. The difference in bolome ...
... 1.5 - Distance to stars: Bolometric magnitude Mbol Magnitudes are measured in some wavelength band. To compare with theory it is more useful to determine bolometric magnitude – defined as absolute magnitude that would be measured by a bolometer* sensi)ve to all wavelengths. The difference in bolome ...
Nucleosynthesis in asymptotic giant branch stars
... must be present in a region of sufficiently high temperature needed for the helium fusion process, that is in excess of 108 K. But since the helium burning proceeds by the triple-alpha process which is extremely temperature dependent, the resulting large energy flux cannot be transported by radiativ ...
... must be present in a region of sufficiently high temperature needed for the helium fusion process, that is in excess of 108 K. But since the helium burning proceeds by the triple-alpha process which is extremely temperature dependent, the resulting large energy flux cannot be transported by radiativ ...
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 ...
Probing the first stars through the abundance of metal poor stars
... Chemical abundances of metal poor stars Probing the first stars – Stellar archeology Looking for the fossil records of early star formation and Galaxy evolution In metal poor systems of Milky way and its satellite galaxies. Complementary to high redshift observations (IGM, GRB, SNs) Nature of Fir ...
... Chemical abundances of metal poor stars Probing the first stars – Stellar archeology Looking for the fossil records of early star formation and Galaxy evolution In metal poor systems of Milky way and its satellite galaxies. Complementary to high redshift observations (IGM, GRB, SNs) Nature of Fir ...
Maximum Mass Limit of Stars on the Main Sequence
... of these objects. Essentially, there are no conclusive observations that indicate whether a slow or a fast method applies to this type of stellar formation. Regardless of the approach, some of the gas in these filaments can become gravitationally bound and begin the collapse necessary to begin the ...
... of these objects. Essentially, there are no conclusive observations that indicate whether a slow or a fast method applies to this type of stellar formation. Regardless of the approach, some of the gas in these filaments can become gravitationally bound and begin the collapse necessary to begin the ...
Surveying the Stars
... • What is the significance of the main sequence? — Normal stars that fuse H to He in their cores fall on the main sequence of an H-R diagram. — A star’s mass determines its position along the main sequence (high mass: luminous and blue; low mass: faint and red). ...
... • What is the significance of the main sequence? — Normal stars that fuse H to He in their cores fall on the main sequence of an H-R diagram. — A star’s mass determines its position along the main sequence (high mass: luminous and blue; low mass: faint and red). ...
Modeling High-Mass X-ray Binary Formation in the Chandra Era Tim Linden
... star is in equilibrium) based on the outcome of the binary interaction, and continue single star evolution ...
... star is in equilibrium) based on the outcome of the binary interaction, and continue single star evolution ...
Properties of Stars Measuring Stars Apparent Magnitude, m Range
... Star seems to move in an ellipse ...
... Star seems to move in an ellipse ...
Slide sem título - Instituto de Física / UFRJ
... IV. Conclusions and Prospects The model adopted allows stable stars to acquire huge charges. However, if we take into account the effects of the electromagnetic fields induced and the surrounding plasma, we come to the conclusion that they are not stable after all. The charge should thus be neutrali ...
... IV. Conclusions and Prospects The model adopted allows stable stars to acquire huge charges. However, if we take into account the effects of the electromagnetic fields induced and the surrounding plasma, we come to the conclusion that they are not stable after all. The charge should thus be neutrali ...
Layers of the Sun Test 1 study guide. Intoduction to Stars
... Temperature of the Sun is constant for any given radius. It doesn’t change as heat flows out Gravitational Force pulling in BALANCES the gas pressure (Electric force) pushing out At center : highest gravitational pressure gives the highest temperature ...
... Temperature of the Sun is constant for any given radius. It doesn’t change as heat flows out Gravitational Force pulling in BALANCES the gas pressure (Electric force) pushing out At center : highest gravitational pressure gives the highest temperature ...
Time From the Perspective of a Particle Physicist
... Temperature of the Sun is constant for any given radius. It doesn’t change as heat flows out Gravitational Force pulling in BALANCES the gas pressure (Electric force) pushing out At center : highest gravitational pressure gives the highest temperature ...
... Temperature of the Sun is constant for any given radius. It doesn’t change as heat flows out Gravitational Force pulling in BALANCES the gas pressure (Electric force) pushing out At center : highest gravitational pressure gives the highest temperature ...
Methods of Determining Relative Age of Young Stellar Objects
... irregular periods, varying by up to four magnitudes. They have associated nebulosity where changes have been observed over the years. On the H-R Diagram, they are on one of the Hayashi Tracks, leading into the main sequence. The goal of this study is that by studying these stars’ spectra, imaging da ...
... irregular periods, varying by up to four magnitudes. They have associated nebulosity where changes have been observed over the years. On the H-R Diagram, they are on one of the Hayashi Tracks, leading into the main sequence. The goal of this study is that by studying these stars’ spectra, imaging da ...