Lec9_2D
... pressure means high temperature, 14,000,000! This energy will (slowly) leak out. • Slow contraction can power the Sun for 40,000,000 years. But to keep it going longer, the energy needs to be replenished. • Energy is added into the Sun’s core by nuclear fusion 4H He. ...
... pressure means high temperature, 14,000,000! This energy will (slowly) leak out. • Slow contraction can power the Sun for 40,000,000 years. But to keep it going longer, the energy needs to be replenished. • Energy is added into the Sun’s core by nuclear fusion 4H He. ...
3.1 Introduction
... In the case of a halo globular cluster, with little foreground contamination, the density of points in the HR diagram approximately reflects the length of time a star spends in different evolutionary stages. Stars spend most of their lives on the main sequence (MS), burning hydrogen in their cores. ...
... In the case of a halo globular cluster, with little foreground contamination, the density of points in the HR diagram approximately reflects the length of time a star spends in different evolutionary stages. Stars spend most of their lives on the main sequence (MS), burning hydrogen in their cores. ...
color-stellar mass diagram
... redshift, we see cosmic epochs of vigorous star formation portion of the Hubble Deep Field galaxies appear more irregular than present day galaxies we see them through the light emitted in UV by the young stars but in UV also nearby galaxies appear less regular ...
... redshift, we see cosmic epochs of vigorous star formation portion of the Hubble Deep Field galaxies appear more irregular than present day galaxies we see them through the light emitted in UV by the young stars but in UV also nearby galaxies appear less regular ...
Chapter 7: The Galaxy, structure and content File
... One reason that these parameters are useful is that A vanishes for solid body rotation (i.e. A = 0 when the angular velocity Ω(R) = hvφ i/R = constant). Another useful property is that the gradient of the rotational velocity is ∂hvφ i/∂R = −(A + B) at R = R0 , which means that A + B = 0 if the rotat ...
... One reason that these parameters are useful is that A vanishes for solid body rotation (i.e. A = 0 when the angular velocity Ω(R) = hvφ i/R = constant). Another useful property is that the gradient of the rotational velocity is ∂hvφ i/∂R = −(A + B) at R = R0 , which means that A + B = 0 if the rotat ...
section 17 powerpoint
... Parallax, denoted as π, is defined as the angle subtended by 1 Astronomical Unit, A.U., at the distance of a star. In practice one can observe the annual displacement of a star resulting from Earth’s orbit about the Sun as 2π. Since all stars should exhibit parallax, measured values (trigonometric p ...
... Parallax, denoted as π, is defined as the angle subtended by 1 Astronomical Unit, A.U., at the distance of a star. In practice one can observe the annual displacement of a star resulting from Earth’s orbit about the Sun as 2π. Since all stars should exhibit parallax, measured values (trigonometric p ...
Stars change over their life cycles.
... their fuel rapidly. After millions of years, a higher-mass star expands to become a supergiant star. In the core of a supergiant, fusion produces heavier and heavier elements. When an iron core forms, fusion stops and gravity causes the core to collapse. Then part of the core bounces outward, and th ...
... their fuel rapidly. After millions of years, a higher-mass star expands to become a supergiant star. In the core of a supergiant, fusion produces heavier and heavier elements. When an iron core forms, fusion stops and gravity causes the core to collapse. Then part of the core bounces outward, and th ...
Chapter10 (with interactive links)
... us in the sky. This generally a number between 0 (very bright) and 6 (faintest human eye can see in a dark sky). A difference in magnitude of 1 is a factor in brightness of 2.5. Venus can have a negative apparent magnitude! ...
... us in the sky. This generally a number between 0 (very bright) and 6 (faintest human eye can see in a dark sky). A difference in magnitude of 1 is a factor in brightness of 2.5. Venus can have a negative apparent magnitude! ...
Spectroscopy Lecture 10
... – Found Sirius B at Northwestern’s Dearborn Observatory Procyon B found in 1895 at Lick – Was it a star that had cooled and dimmed? Spectrum of 40 Eri B observed – an A star! – It must be hot – Must have small radius to be so faint – The first “w hite dwarf” Adams found Sirius B is also an A star ...
... – Found Sirius B at Northwestern’s Dearborn Observatory Procyon B found in 1895 at Lick – Was it a star that had cooled and dimmed? Spectrum of 40 Eri B observed – an A star! – It must be hot – Must have small radius to be so faint – The first “w hite dwarf” Adams found Sirius B is also an A star ...
Stellar Characteristics and Evolution
... helium-burning shell is not very stable - this causes the star to pulsate in both size and luminosity. As time goes on these pulsations get more and more severe (stars in this stage are sometimes known as the “Mira Giants”), becoming so great that the star actually starts to shed significant amounts ...
... helium-burning shell is not very stable - this causes the star to pulsate in both size and luminosity. As time goes on these pulsations get more and more severe (stars in this stage are sometimes known as the “Mira Giants”), becoming so great that the star actually starts to shed significant amounts ...
3. Celestial Sphere Mark
... Do all locations on Earth see the same Visible Sky Simulation motion of the stars? ...
... Do all locations on Earth see the same Visible Sky Simulation motion of the stars? ...
Foreword - Peter Zamarovský
... shell’s radius, i.e. with a quarter of the distance from Earth. The intensity of the light from the individual stars, on the other hand, is inversely proportional to the square of the distance from the source4. The two relationships disrupt each other so all the shells ought to contribute equally to ...
... shell’s radius, i.e. with a quarter of the distance from Earth. The intensity of the light from the individual stars, on the other hand, is inversely proportional to the square of the distance from the source4. The two relationships disrupt each other so all the shells ought to contribute equally to ...
Lecture notes 1: The human eye
... fatigue occurs when staring fixedly at a source for an extended period due to depletion of the sensitive pigment. The Rayleigh limit of the eye, roughly given by λ/D where λ is the wavelength of the observed light and D is the size of the observing aperture, is of order 20 arcsec when the iris has i ...
... fatigue occurs when staring fixedly at a source for an extended period due to depletion of the sensitive pigment. The Rayleigh limit of the eye, roughly given by λ/D where λ is the wavelength of the observed light and D is the size of the observing aperture, is of order 20 arcsec when the iris has i ...
Sparta High School
... What can astronomy tell us about the human race and planet Earth? Why spend the time and money? How do we know so much about distant space if we can’t travel there? How big is “big” and how long is a “long time”? Where are we located in the solar system, galaxy and universe? How do modern astronomer ...
... What can astronomy tell us about the human race and planet Earth? Why spend the time and money? How do we know so much about distant space if we can’t travel there? How big is “big” and how long is a “long time”? Where are we located in the solar system, galaxy and universe? How do modern astronomer ...
Yeatman-Liddell College Preparatory Middle School Winter
... Unlike our Sun, giant stars contract or draw in upon themselves. They begin to absorb energy instead ...
... Unlike our Sun, giant stars contract or draw in upon themselves. They begin to absorb energy instead ...
OUR SOLAR SYSTEM
... and numbers using familiar units already are cumbersome. So astronomers devised the astronomical unit (AU; see “Solar system yardstick,” p. 26) as a simpler way to express distances at the scale of planetary orbits. The average distance from Earth to the Sun represents 1 AU. Mercury lies closest to ...
... and numbers using familiar units already are cumbersome. So astronomers devised the astronomical unit (AU; see “Solar system yardstick,” p. 26) as a simpler way to express distances at the scale of planetary orbits. The average distance from Earth to the Sun represents 1 AU. Mercury lies closest to ...
Lecture 10
... *All stars above 6,000 K look more or less white to the human eye because they emit plenty of radiation at all visible wavelengths. ...
... *All stars above 6,000 K look more or less white to the human eye because they emit plenty of radiation at all visible wavelengths. ...
Chapter 3 Cosmology 3.1 The Doppler effect
... in Andromeda that he had identified. He then used data obtained on Cepheid variables of known absolute magnitudes to find the absolute magnitude and hence the distance to each Cepheid variable in Andromeda. He found that Andromeda is about 900 kiloparsec away, far beyond the Milky Way galaxy which w ...
... in Andromeda that he had identified. He then used data obtained on Cepheid variables of known absolute magnitudes to find the absolute magnitude and hence the distance to each Cepheid variable in Andromeda. He found that Andromeda is about 900 kiloparsec away, far beyond the Milky Way galaxy which w ...
High Mass Stars
... – From H-R diagram its luminosity is 100000 times greater than the Sun’s. – It therefore burns fuel (uses it’s mass) 100000 times faster than the Sun. – It has 25 times the mass of the Sun so its lifetime will be 25/100000 = 0.00025 times than the Sun’s lifetime = 2.5 million years. ...
... – From H-R diagram its luminosity is 100000 times greater than the Sun’s. – It therefore burns fuel (uses it’s mass) 100000 times faster than the Sun. – It has 25 times the mass of the Sun so its lifetime will be 25/100000 = 0.00025 times than the Sun’s lifetime = 2.5 million years. ...
Ursa Major
Ursa Major /ˈɜrsə ˈmeɪdʒər/ (also known as the Great Bear and Charles' Wain) is a constellation in the northern celestial hemisphere. One of the 48 constellations listed by Ptolemy (second century AD), it remains one of the 88 modern constellations. It can be visible throughout the year in most of the northern hemisphere. Its name, Latin for ""the greater (or larger) she-bear"", stands as a reference to and in direct contrast with Ursa Minor, ""the smaller she-bear"", with which it is frequently associated in mythology and amateur astronomy. The constellation's most recognizable asterism, a group of seven relatively bright stars commonly known as the ""Big Dipper"", ""the Wagon"" or ""the Plough"" (among others), both mimicks the shape of the lesser bear (the ""Little Dipper"") and is commonly used as a navigational pointer towards the current northern pole star, Polaris in Ursa Minor. The Big Dipper and the constellation as a whole have mythological significance in numerous world cultures, usually as a symbol of the north.The third largest constellation in the sky, Ursa Major is home to many deep-sky objects including seven Messier objects, four other NGC objects and I Zwicky 18, the youngest known galaxy in the visible universe.