– 1 – 1. Cosmochronology
... must have detectable spectral features in a suitable region of the stellar spectrum. Again important in the case of stars, where elemental abundances can be measured, but almost all isotopic abundances cannot, the element involved must have no stable isotope which has an abundance larger than the ra ...
... must have detectable spectral features in a suitable region of the stellar spectrum. Again important in the case of stars, where elemental abundances can be measured, but almost all isotopic abundances cannot, the element involved must have no stable isotope which has an abundance larger than the ra ...
The Bigger Picture - Astronomy and Astrophysics
... • The inverse square law is due to geometric dilution of the light. At each radius you have the same total amount of light going through the surface of an imaginary sphere. Surface area of a sphere increases like R2. • The light/area therefore decreases like 1/R2 ...
... • The inverse square law is due to geometric dilution of the light. At each radius you have the same total amount of light going through the surface of an imaginary sphere. Surface area of a sphere increases like R2. • The light/area therefore decreases like 1/R2 ...
ASTR_PNE_lightII_V01.docx
... atmosphere. Which of the following spectra would you observe by analyzing the sunlight? ...
... atmosphere. Which of the following spectra would you observe by analyzing the sunlight? ...
solutions 3
... 4. Pauli Pressure and White Dwarf stars A star like the Sun is essentially a box of hydrogen, held together by gravity. After 10 billion years or so, the core of the star contains enough helium and other fusion products that the fusion processes slow down and the star begins to cool and contract. Ev ...
... 4. Pauli Pressure and White Dwarf stars A star like the Sun is essentially a box of hydrogen, held together by gravity. After 10 billion years or so, the core of the star contains enough helium and other fusion products that the fusion processes slow down and the star begins to cool and contract. Ev ...
Life of the Sun—16 Oct
... pressure. How does the sun adjust? • Without burning fuel to keep temperature up, pressure (PV=nRT) would fall and gravity would win. • Core shrinks, gets hotter • H→He in the a shell surrounding inert core • Balance restored. ...
... pressure. How does the sun adjust? • Without burning fuel to keep temperature up, pressure (PV=nRT) would fall and gravity would win. • Core shrinks, gets hotter • H→He in the a shell surrounding inert core • Balance restored. ...
Goal: To understand the HR diagram
... • Color = B-V = temperature • Since the top left stars on the main sequence die first the top left is always peeling off of the main sequence. • The position where there is turn off tells you the age of the cluster • The comparison of absolute to apparent magnitudes tells you the distance to the clu ...
... • Color = B-V = temperature • Since the top left stars on the main sequence die first the top left is always peeling off of the main sequence. • The position where there is turn off tells you the age of the cluster • The comparison of absolute to apparent magnitudes tells you the distance to the clu ...
AST 207 7 Homew
... m sequencce because theey all already used up theirr There are no hotter stars on the main gen cores and d left the main n sequence. H Hotter stars usse up their fuel faster. hydrog c. Stars with w a color B-V=0.6 span a range of 5 m magnitudes. (22 pts.) What pproperty of thee stars accoun nts for ...
... m sequencce because theey all already used up theirr There are no hotter stars on the main gen cores and d left the main n sequence. H Hotter stars usse up their fuel faster. hydrog c. Stars with w a color B-V=0.6 span a range of 5 m magnitudes. (22 pts.) What pproperty of thee stars accoun nts for ...
Way Milky the MAPPING
... In their work, Quillen and her colleagues focused on the forces acting on the stars in or near the bulge. As the stars go through their orbits, they also move above and below the plane of the bar. And like a child on a swing, each time a star crosses the plane of the bar at what’s known as the reson ...
... In their work, Quillen and her colleagues focused on the forces acting on the stars in or near the bulge. As the stars go through their orbits, they also move above and below the plane of the bar. And like a child on a swing, each time a star crosses the plane of the bar at what’s known as the reson ...
ppt - University of Cambridge
... – If we can measure the rate that they are blinking then we can infer how bright they are. – Then we compare how bright they look to us and how bright they are as calculated from their blink rate. – Distance ...
... – If we can measure the rate that they are blinking then we can infer how bright they are. – Then we compare how bright they look to us and how bright they are as calculated from their blink rate. – Distance ...
Star formation PowerPoint
... Most important: Stars do not move along the main sequence! Once they reach it, they are in equilibrium and do not move until their fuel begins to run out. ...
... Most important: Stars do not move along the main sequence! Once they reach it, they are in equilibrium and do not move until their fuel begins to run out. ...
Target Stars for Earth-like Planet Searches with the Terrestrial
... basic parameters for an Earth-like planet near each of the stars, including the diameter of the Habitable Zone (HZ). For these purposes, the HZ is defined as the distance from the star at which an Earth-like planet would have the same equilibrium temperature as Earth. (3) Select those stars for whic ...
... basic parameters for an Earth-like planet near each of the stars, including the diameter of the Habitable Zone (HZ). For these purposes, the HZ is defined as the distance from the star at which an Earth-like planet would have the same equilibrium temperature as Earth. (3) Select those stars for whic ...
How Common is Life in the Milky Way?
... Now work with others in your group to estimate the following quantities based on your new knowledge of astronomy. This is just an estimate, so use powers of 10 to make the math easy. The Milky Way contains about 1011 stars. What fraction of the stars are similar to the Sun? _________________________ ...
... Now work with others in your group to estimate the following quantities based on your new knowledge of astronomy. This is just an estimate, so use powers of 10 to make the math easy. The Milky Way contains about 1011 stars. What fraction of the stars are similar to the Sun? _________________________ ...
Stellar Evolution Project:
... For this assignment, you will create a poster/study chart on the evolution of a stars life cycle. This poster will include an expanded version of the diagram found on pages 786 & 787 of your textbook (figure 8). However, you need to add a black hole and a nova to this diagram. You will also have to ...
... For this assignment, you will create a poster/study chart on the evolution of a stars life cycle. This poster will include an expanded version of the diagram found on pages 786 & 787 of your textbook (figure 8). However, you need to add a black hole and a nova to this diagram. You will also have to ...
Pulsations in White Dwarfs
... modes in an evolving model with a fixed PG1159 envelope composition (red dots), and that of a model in which stellar winds and gravitational settling are taken into account (black dots). The latter suggests that a GW Vir star (PG1159 spectral type) should again pulsate in its lifetime but, this time ...
... modes in an evolving model with a fixed PG1159 envelope composition (red dots), and that of a model in which stellar winds and gravitational settling are taken into account (black dots). The latter suggests that a GW Vir star (PG1159 spectral type) should again pulsate in its lifetime but, this time ...
Life of a Star - University of Texas Astronomy Home Page
... SOL: Oh not very long – a moment. 100,000 years. PAGE: What about the gas law? Did that factor into this phase of your life? SOL: Certainly. As the density and pressure increased, so did the temperature. At my core, I was about 106 Kelvin. And then, of course, the outer layers were cooler. PAGE: Wow ...
... SOL: Oh not very long – a moment. 100,000 years. PAGE: What about the gas law? Did that factor into this phase of your life? SOL: Certainly. As the density and pressure increased, so did the temperature. At my core, I was about 106 Kelvin. And then, of course, the outer layers were cooler. PAGE: Wow ...
University of Groningen Mass loss and rotational CO emission
... and profiles, a physical structure with a variable mass-loss rate and/or a gradient in stochastic gas velocity is required. A case study of the AGB star WX Psc is performed. We find that the CO line strengths may be explained by variations in mass-loss on time scales similar to those observed in the ...
... and profiles, a physical structure with a variable mass-loss rate and/or a gradient in stochastic gas velocity is required. A case study of the AGB star WX Psc is performed. We find that the CO line strengths may be explained by variations in mass-loss on time scales similar to those observed in the ...
www.astro.caltech.edu
... The origin of these events was debated for decades, and hundreds of ideas were presented in scientific journals during the 1970s and 1980s to interpret this discovery. Most models relied on explosions on the surfaces of compact stars such as white dwarfs within (or in the halo of) our Milky Way Gala ...
... The origin of these events was debated for decades, and hundreds of ideas were presented in scientific journals during the 1970s and 1980s to interpret this discovery. Most models relied on explosions on the surfaces of compact stars such as white dwarfs within (or in the halo of) our Milky Way Gala ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.