d = 1 / p
... To do this in practice, first find the energy per second emitted by each unit of surface area, ε, using the relation given in class (ε = σ T 4). The luminosity of a star is given by the power emitted per unit area times its surface area (L = ε S); for a sphere, S = 4π R2, so L = ε S = (σ T4)(4π R2). ...
... To do this in practice, first find the energy per second emitted by each unit of surface area, ε, using the relation given in class (ε = σ T 4). The luminosity of a star is given by the power emitted per unit area times its surface area (L = ε S); for a sphere, S = 4π R2, so L = ε S = (σ T4)(4π R2). ...
d = 1 / p
... Expressing this in terms of radius, R = (L / (4π σ T )) . Never confuse the radius of the star R with the distance to the star d! Although both are measures of length that appear in our equations squared and multiplied by 4π, they are extremely different! In addition, keep in mind that the Stefan-Bo ...
... Expressing this in terms of radius, R = (L / (4π σ T )) . Never confuse the radius of the star R with the distance to the star d! Although both are measures of length that appear in our equations squared and multiplied by 4π, they are extremely different! In addition, keep in mind that the Stefan-Bo ...
Can you write numbers in scientific notation
... Do you know the surface temperature, total lifespan, and general composition of the Sun? How is the process of stellar parallax used to determine the distance to a star? Do you understand how the brightness of a star depends on the star’s luminosity and the distance an observer is away from the star ...
... Do you know the surface temperature, total lifespan, and general composition of the Sun? How is the process of stellar parallax used to determine the distance to a star? Do you understand how the brightness of a star depends on the star’s luminosity and the distance an observer is away from the star ...
Lecture 5: Stars
... We only know the absolute luminosity if we know the distance, but we only know the parallax distances out to about 100 pc (further to some bright stars). The problem is that if we see a star with a surface temperature of 3000K – is it a nearby red dwarf, or a distant red giant? Without more informat ...
... We only know the absolute luminosity if we know the distance, but we only know the parallax distances out to about 100 pc (further to some bright stars). The problem is that if we see a star with a surface temperature of 3000K – is it a nearby red dwarf, or a distant red giant? Without more informat ...
Powerpoint for today
... temperature from spectrum (black-body curve or spectral lines), then find surface area, then find radius (sphere surface area is 4 p R2) ...
... temperature from spectrum (black-body curve or spectral lines), then find surface area, then find radius (sphere surface area is 4 p R2) ...
The universe is faster, colder, and wackier than anything we can
... with their feeble gravity and take up a fragile orbit around each other. Of the many binary pairs of small galaxies we know of, the pair that is bound together most weakly is an obscure duo known as SDSS J113342.7+482004.9 and SDSS J113403.9+482837.4, or as I like to call them, Napoleon and Josephin ...
... with their feeble gravity and take up a fragile orbit around each other. Of the many binary pairs of small galaxies we know of, the pair that is bound together most weakly is an obscure duo known as SDSS J113342.7+482004.9 and SDSS J113403.9+482837.4, or as I like to call them, Napoleon and Josephin ...
The supernova of AD1181 – an update
... Recently it has become clear that not only is 3C 58 much less luminous than the Crab nebula, despite being about the same age, but also that (see Green and Scheuer 1993 or Woltjer et al. 1997) the form of its synchrotron spectrum is quite different from that of the Crab. The flat radio spectra of th ...
... Recently it has become clear that not only is 3C 58 much less luminous than the Crab nebula, despite being about the same age, but also that (see Green and Scheuer 1993 or Woltjer et al. 1997) the form of its synchrotron spectrum is quite different from that of the Crab. The flat radio spectra of th ...
So why are more massive stars more luminous?
... luminosity has gone up by about 40%. These changes in the core have made the Sun’s outer layers expand in radius by 6% and increased the surface temperature from 5500 K to 5800 K. ...
... luminosity has gone up by about 40%. These changes in the core have made the Sun’s outer layers expand in radius by 6% and increased the surface temperature from 5500 K to 5800 K. ...
Crux The Southern Cross
... the main stars of Crux. Make a point of viewing all five of the main Crux stars. Note the colours, which are double, brightness differences, and anything else interesting you find. ...
... the main stars of Crux. Make a point of viewing all five of the main Crux stars. Note the colours, which are double, brightness differences, and anything else interesting you find. ...
mslien~1
... From above the Jeans criterion can be derived as M c M J where the Jeans mass MJ is given by the RHS of ...
... From above the Jeans criterion can be derived as M c M J where the Jeans mass MJ is given by the RHS of ...
Astronomy 100—Exam 2
... C. giant stars have lifetimes that are very short compared to the main sequence stage. D. elements heavier than helium are relatively rare. E. none of the above. 34. If the rate of hydrogen fusion within the Sun were to decrease, the core of the Sun would A. contract and decrease in temperature. D. ...
... C. giant stars have lifetimes that are very short compared to the main sequence stage. D. elements heavier than helium are relatively rare. E. none of the above. 34. If the rate of hydrogen fusion within the Sun were to decrease, the core of the Sun would A. contract and decrease in temperature. D. ...
Lecture21 - UCSB Physics
... has gone up by about 40%. These changes in the core have made the Sun’s outer layers expand in radius by 6% and increased the surface temperature from 5500 K to 5800 K. ...
... has gone up by about 40%. These changes in the core have made the Sun’s outer layers expand in radius by 6% and increased the surface temperature from 5500 K to 5800 K. ...
nightwatch sheet june 2017 - National Museums Liverpool
... of Ophiuchus. The ringed world shines at a steady magnitude of 0.0 and reaches opposition on the 15th. The moon passes to the north of Saturn on the 10th. The June Bootids is an unpredictable meteor shower, if you’d like to try and see it the shower begins on the 22nd and peaks on the 27th. It conti ...
... of Ophiuchus. The ringed world shines at a steady magnitude of 0.0 and reaches opposition on the 15th. The moon passes to the north of Saturn on the 10th. The June Bootids is an unpredictable meteor shower, if you’d like to try and see it the shower begins on the 22nd and peaks on the 27th. It conti ...
Chapter2
... IV. The Motion of the Planets A. The Moving Planets B. Astrology V. Astronomical Influences on Earth's Climate A. The Hypothesis B. The Evidence ...
... IV. The Motion of the Planets A. The Moving Planets B. Astrology V. Astronomical Influences on Earth's Climate A. The Hypothesis B. The Evidence ...
13 - Joe Griffin Media Ministries
... calendar is lunar and its days start at sundown whereas the other three are solar and start at midnight. To assert with confidence that the crucifixion occurred on Friday is a claim I’d like to see verified. Nevertheless, the phrase “three days and three nights” used by our Lord in Matthew 12:40, tr ...
... calendar is lunar and its days start at sundown whereas the other three are solar and start at midnight. To assert with confidence that the crucifixion occurred on Friday is a claim I’d like to see verified. Nevertheless, the phrase “three days and three nights” used by our Lord in Matthew 12:40, tr ...
Environmental Science
... pattern rather than pointing at a single spot or staying mostly still. If you draw an imaginary line of the earth's axis and continue it up to the sky, it will make a similar path. This type of axis rotation is called precession. In the case of the earth, precession is caused by the gravitational pu ...
... pattern rather than pointing at a single spot or staying mostly still. If you draw an imaginary line of the earth's axis and continue it up to the sky, it will make a similar path. This type of axis rotation is called precession. In the case of the earth, precession is caused by the gravitational pu ...
Precession of Earth
... pattern rather than pointing at a single spot or staying mostly still. If you draw an imaginary line of the earth's axis and continue it up to the sky, it will make a similar path. This type of axis rotation is called precession. In the case of the earth, precession is caused by the gravitational pu ...
... pattern rather than pointing at a single spot or staying mostly still. If you draw an imaginary line of the earth's axis and continue it up to the sky, it will make a similar path. This type of axis rotation is called precession. In the case of the earth, precession is caused by the gravitational pu ...
Star Evolution
... • From expansion velocity of ~10 km/sec the distance is 1000 lightyears • From distance and apparent size the linear size is ~a light year ...
... • From expansion velocity of ~10 km/sec the distance is 1000 lightyears • From distance and apparent size the linear size is ~a light year ...
NAME_______________________________________
... A) the emission of specific elements B) different chemical elements which absorb light at specific wavelengths C) highly compressed, glowing gas D) warmer gas in front of a source that emits a continuous spectrum ____ 16. The apparent shift in a star’s position caused by the motion of the observer i ...
... A) the emission of specific elements B) different chemical elements which absorb light at specific wavelengths C) highly compressed, glowing gas D) warmer gas in front of a source that emits a continuous spectrum ____ 16. The apparent shift in a star’s position caused by the motion of the observer i ...
Problem Set 6 for Astro 320 Read sections 11.2
... Due Nov. 18, by 5 pm, to the Astro 320 drop box. Problem 1: a) C & O, problem 11.2a. The Sun’s luminosity is 3.8 × 1026 W, or J/s. That translates, via E = mc2 , to m = E/c2 = 3.8 × 1026 /(3 × 108 )2 = 4 × 109 kg/s. Per year, that’s 3.16 × 107 ∗ 4 × 109 = 1.26 × 1017 kg/year, or 6.3 × 10−14 M /year ...
... Due Nov. 18, by 5 pm, to the Astro 320 drop box. Problem 1: a) C & O, problem 11.2a. The Sun’s luminosity is 3.8 × 1026 W, or J/s. That translates, via E = mc2 , to m = E/c2 = 3.8 × 1026 /(3 × 108 )2 = 4 × 109 kg/s. Per year, that’s 3.16 × 107 ∗ 4 × 109 = 1.26 × 1017 kg/year, or 6.3 × 10−14 M /year ...
here
... it also absorbs the outward directed momentum of the photons which leads to an additional outward force – radiation pressure. For too massive stars, radiation pressure would exceed gravity, know as the “Eddington limit”, which prevents such stars from forming. However, these limits are disputed (see ...
... it also absorbs the outward directed momentum of the photons which leads to an additional outward force – radiation pressure. For too massive stars, radiation pressure would exceed gravity, know as the “Eddington limit”, which prevents such stars from forming. However, these limits are disputed (see ...
star
... closer to Earth than other stars. In fact, the sun is really a star of only average brightness. Apparent brightness-‐ the brightness of a star as it appears from Earth. ...
... closer to Earth than other stars. In fact, the sun is really a star of only average brightness. Apparent brightness-‐ the brightness of a star as it appears from Earth. ...
The Life of a Star
... reaches 1.0 x 106°C, helium fusion begins in the core (secondary fusion). Once all fusion reactions stop, the star throws its outer layers into space, forming a planetary nebula – This leaves behind the hot dense core of the red giant. – The remaining core is called a white dwarf. Over time, the whi ...
... reaches 1.0 x 106°C, helium fusion begins in the core (secondary fusion). Once all fusion reactions stop, the star throws its outer layers into space, forming a planetary nebula – This leaves behind the hot dense core of the red giant. – The remaining core is called a white dwarf. Over time, the whi ...
Perseus (constellation)
Perseus, named after the Greek mythological hero Perseus, is a constellation in the northern sky. It was one of 48 listed by the 2nd-century astronomer Ptolemy and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located in the northern celestial hemisphere near several other constellations named after legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west.The galactic plane of the Milky Way passes through Perseus but is mostly obscured by molecular clouds. The constellation's brightest star is the yellow-white supergiant Alpha Persei (also called Mirfak), which shines at magnitude 1.79. It and many of the surrounding stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol (Beta Persei), linked with ominous legends because of its variability, which is noticeable to the naked eye. Rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a binary system containing a neutron star, and GK Persei, a nova that peaked at magnitude 0.2 in 1901. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese. The constellation gives its name to the Perseus Cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth. It hosts the radiant of the annual Perseids meteor shower—one of the most prominent meteor showers in the sky.