WASP-7: The brightest transiting-exoplanet system in the Southern
... and Mg i b lines. An estimate of the microturbulence (ξt ) comes from several clean and unblended Fe i and Fe ii lines, while the ionization balance between Fe i and Fe ii was used as an additional diagnostic of Teff and log g. In addition to the spectral analysis, we have also used TYCHO, DENIS and ...
... and Mg i b lines. An estimate of the microturbulence (ξt ) comes from several clean and unblended Fe i and Fe ii lines, while the ionization balance between Fe i and Fe ii was used as an additional diagnostic of Teff and log g. In addition to the spectral analysis, we have also used TYCHO, DENIS and ...
Bluffer`s Guide to Orion
... sky. Sirius is the prominent star in the lower left, and part of Taurus can be seen at upper right. Diagram created with Starry Night software. years away and thirty light years across, and is the closest region of star formation to Earth. A lot of what proper astronomers know about how stars and pl ...
... sky. Sirius is the prominent star in the lower left, and part of Taurus can be seen at upper right. Diagram created with Starry Night software. years away and thirty light years across, and is the closest region of star formation to Earth. A lot of what proper astronomers know about how stars and pl ...
Origin of close binary systems
... --------------1) Some of the most exciting cosmic phenemena due to the presence of massive close binaries 2) Studies of star forming regions & young clusters allow us to observe binary parameter distributions give extra info on massive star formation provide I.C. for models of interacting binary evo ...
... --------------1) Some of the most exciting cosmic phenemena due to the presence of massive close binaries 2) Studies of star forming regions & young clusters allow us to observe binary parameter distributions give extra info on massive star formation provide I.C. for models of interacting binary evo ...
AstroBITS: Open Cluster Project I. Introduction The observational
... produces an H-R diagram which can be compared with a H-R diagram for a clusters whose distance is known from other methods (parallax, which we discussed in module 6). And from the inverse square law for light ( light intensity falls off inversely as the square of the distance) we can then get the di ...
... produces an H-R diagram which can be compared with a H-R diagram for a clusters whose distance is known from other methods (parallax, which we discussed in module 6). And from the inverse square law for light ( light intensity falls off inversely as the square of the distance) we can then get the di ...
(convective) core of a star
... Because of higher Coulomb barrier He burning requires much higher temperatures à drastic change in central temperature à star has to readjust to a new configuration Qualitative argument: • need about the same Luminosity – similar temperature gradient dT/dr • now much higher Tc – need larger st ...
... Because of higher Coulomb barrier He burning requires much higher temperatures à drastic change in central temperature à star has to readjust to a new configuration Qualitative argument: • need about the same Luminosity – similar temperature gradient dT/dr • now much higher Tc – need larger st ...
Gravitational Wave Generation in Rotating Compact Stars
... determined for the mass M = 1.6 M , provided the initial angular momentum L0 . We consider in this work two different values of the initial angular momentum. For L0 = 1.8 × 1049 g · cm2 · s−1 we obtain the initial values for the semi-axes of the ellipsoid a1 (0) = 2.05 × 106 cm, a2 (0) = 1.59 × 106 ...
... determined for the mass M = 1.6 M , provided the initial angular momentum L0 . We consider in this work two different values of the initial angular momentum. For L0 = 1.8 × 1049 g · cm2 · s−1 we obtain the initial values for the semi-axes of the ellipsoid a1 (0) = 2.05 × 106 cm, a2 (0) = 1.59 × 106 ...
How is Light Made?
... Now the particle nature of EM radiation. These little packets of light is known as photons. These photons carry a certain energy which is related to its frequency. This energy is equal to Planck’s constant (h) multiplied by the frequency of the photon. By substituting “nu” with the equation in the p ...
... Now the particle nature of EM radiation. These little packets of light is known as photons. These photons carry a certain energy which is related to its frequency. This energy is equal to Planck’s constant (h) multiplied by the frequency of the photon. By substituting “nu” with the equation in the p ...
Untitled
... Crab. Praesepe is also called the Beehive cluster, the reason obvious when it is viewed in binoculars. Praespe is 600 l.y away. Its stars are 600 million years old. The biggest and brightest stars in the original cluster have long ago burnt out so only the medium-brightness stars remain. This gives ...
... Crab. Praesepe is also called the Beehive cluster, the reason obvious when it is viewed in binoculars. Praespe is 600 l.y away. Its stars are 600 million years old. The biggest and brightest stars in the original cluster have long ago burnt out so only the medium-brightness stars remain. This gives ...
Unit 6: Space - Galena Park ISD
... speed of light is constant, you can measure how long it takes for light to reach an object and then calculate the distance it resides from that object. The student is expected to model and describe how light years are used to measure distances and sizes in the universe. (8.8D) Light travels at 300,0 ...
... speed of light is constant, you can measure how long it takes for light to reach an object and then calculate the distance it resides from that object. The student is expected to model and describe how light years are used to measure distances and sizes in the universe. (8.8D) Light travels at 300,0 ...
Can the sun make it rain, or (Will astronomy help us
... • SN1987A was the first Supernovae in hundreds of years that was visible by eye ...
... • SN1987A was the first Supernovae in hundreds of years that was visible by eye ...
![[WC 6] nucleus with other emission-lines nuclei of planetary nebulae](http://s1.studyres.com/store/data/004159324_1-0806f9baff29e598ec0946db112c7fad-300x300.png)
[WC 6] nucleus with other emission-lines nuclei of planetary nebulae
... [WC]-type CSPN, 38 are assigned to a "weak emission-lines star" CSPN (wels) class, 2 are WN8 stars belonging most probably to pop.I WR stars (Tylenda et al, 1993) , and about 15 are of uncertain class. The [WC] nuclei mostly populate subclasses [WC 3-4] and [WC 9-11] whereas the Population I WC star ...
... [WC]-type CSPN, 38 are assigned to a "weak emission-lines star" CSPN (wels) class, 2 are WN8 stars belonging most probably to pop.I WR stars (Tylenda et al, 1993) , and about 15 are of uncertain class. The [WC] nuclei mostly populate subclasses [WC 3-4] and [WC 9-11] whereas the Population I WC star ...
double shell–burning
... Brown Dwarfs • A brown dwarf emits infrared light because of heat left over from contraction. • Its luminosity gradually declines with time as it loses thermal energy. ...
... Brown Dwarfs • A brown dwarf emits infrared light because of heat left over from contraction. • Its luminosity gradually declines with time as it loses thermal energy. ...
Model Solutions
... Solution: The proton plate A and plate C are positively charged, hence if the proton is displaced towards plate A, then it will get repelled and return to its equilibrium position i.e. the centre of the assembly. Conversely, plate B and plate D are negatively charged, so if the proton is displaced t ...
... Solution: The proton plate A and plate C are positively charged, hence if the proton is displaced towards plate A, then it will get repelled and return to its equilibrium position i.e. the centre of the assembly. Conversely, plate B and plate D are negatively charged, so if the proton is displaced t ...
Major constellations
... A conspicious constellation of the northern hemisphere. It belongs to the Hercules constellation family. The stars forming the swans body resemble a cross, so sometimes this constellation is refered as Northern Cross. The brightest star, alpha Cyg, called Deneb (arab.: the tail), is among the 20 bri ...
... A conspicious constellation of the northern hemisphere. It belongs to the Hercules constellation family. The stars forming the swans body resemble a cross, so sometimes this constellation is refered as Northern Cross. The brightest star, alpha Cyg, called Deneb (arab.: the tail), is among the 20 bri ...
On the Progenitors of Type Ia Supernovae
... everything: prompt are caused by accretion from young main sequence stars (~8M☉), and delayed are caused by accretion from red giant companions (~1M☉). However, models involve maybe too many “moving parts.” ...
... everything: prompt are caused by accretion from young main sequence stars (~8M☉), and delayed are caused by accretion from red giant companions (~1M☉). However, models involve maybe too many “moving parts.” ...
The accretion properties of the intermediate mass Herbig Ae/Be stars
... GAIA – cluster work – 3D picture of clusters, age determinations Line profile correlations provide information on accretion process CO emission at 2.3 micron (Ilee+2014) ...
... GAIA – cluster work – 3D picture of clusters, age determinations Line profile correlations provide information on accretion process CO emission at 2.3 micron (Ilee+2014) ...
Dark matter in the Galactic Halo Rotation curve (i.e. the orbital
... • for the inner Galaxy by looking at the Doppler shift of 21 cm emission from hydrogen • for the outer Galaxy by looking at the velocity of star clusters relative to the Sun. (details of these methods are given in Section 2.3 of Sparke & Gallagher…) ...
... • for the inner Galaxy by looking at the Doppler shift of 21 cm emission from hydrogen • for the outer Galaxy by looking at the velocity of star clusters relative to the Sun. (details of these methods are given in Section 2.3 of Sparke & Gallagher…) ...
Chapter 13: Neutron Stars and Black Holes - Otto
... • Ball of neutrons remain - neutron star • 20 km or so across (size of major city) • Mass greater than sun • Density 1017 to 1018 kg/m3 • Thimbleful would weigh 100 million tons • 150 lb human on surface would weigh 1 ...
... • Ball of neutrons remain - neutron star • 20 km or so across (size of major city) • Mass greater than sun • Density 1017 to 1018 kg/m3 • Thimbleful would weigh 100 million tons • 150 lb human on surface would weigh 1 ...
Lecture 14
... spheres are called Stromgren spheres. At the outer boundary, there is some recombination. With the short lifetime of massive, UV-creating stars, the size of Stromgren spheres often reaches a ...
... spheres are called Stromgren spheres. At the outer boundary, there is some recombination. With the short lifetime of massive, UV-creating stars, the size of Stromgren spheres often reaches a ...
Major Themes of “ The First Stars ”
... major implications for observable features of galaxies by JWST. 4. A new synthesis of theory is being developed to take advantage of this wealth of data, and connect it explicitly to high-z, as a perfect partner and complement to JWST. In the JWST era, we can test and extend these models to uncover ...
... major implications for observable features of galaxies by JWST. 4. A new synthesis of theory is being developed to take advantage of this wealth of data, and connect it explicitly to high-z, as a perfect partner and complement to JWST. In the JWST era, we can test and extend these models to uncover ...
The Origin of Light
... are required to activate uranium 238, and slower ones work for uranium 235. The reaction also produces neutrons, so a chain reaction can occur to fuel power stations if controlled or an explosion if uncontrolled. Only a brief description is given here because fission is not the nuclear reaction that ...
... are required to activate uranium 238, and slower ones work for uranium 235. The reaction also produces neutrons, so a chain reaction can occur to fuel power stations if controlled or an explosion if uncontrolled. Only a brief description is given here because fission is not the nuclear reaction that ...
Where Do Baby Stars Come From?
... cause the dark molecular cloud to start spinning. Each of the fragments within it will spin. As they collapse it’s sort of like an ice skater pulling her arms in towards her body. As you get your distribution of mass closer and closer to the centre of the mass, an object spins faster and faster. As ...
... cause the dark molecular cloud to start spinning. Each of the fragments within it will spin. As they collapse it’s sort of like an ice skater pulling her arms in towards her body. As you get your distribution of mass closer and closer to the centre of the mass, an object spins faster and faster. As ...
–1– 4. Energy transport in stars Stars are hotter at the centre, hence
... unperturbed. So the momentum of the particle is p = px = mv. Now we put in an ion with a minimum impact parameter b. Clearly most deflections occur at when |x| < ∼ b, and hence the duration of the interaction is ∼ 2b/v. Let us consider the y-component of the momentum gained by the electron by assumi ...
... unperturbed. So the momentum of the particle is p = px = mv. Now we put in an ion with a minimum impact parameter b. Clearly most deflections occur at when |x| < ∼ b, and hence the duration of the interaction is ∼ 2b/v. Let us consider the y-component of the momentum gained by the electron by assumi ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.