part iv: stars i
... sequence; cf. Section 10.7), it must be the case that the Eddington Luminosity imposes an upper limit to the mass of stable stars. (In practice, instabilities cause a super-Eddington atmosphere to become clumpy, or `porous', and radiation is able to escape through paths of lowered optical depth betw ...
... sequence; cf. Section 10.7), it must be the case that the Eddington Luminosity imposes an upper limit to the mass of stable stars. (In practice, instabilities cause a super-Eddington atmosphere to become clumpy, or `porous', and radiation is able to escape through paths of lowered optical depth betw ...
Chapter 8
... Note that the following lectures include animations and PowerPoint effects such as ...
... Note that the following lectures include animations and PowerPoint effects such as ...
Wonderful eclipses
... First, what if the Moon were significantly closer to the Earth? About 2.5 Gyrs ago the Moon’s mean distance from the Earth was about 87% its present value (Walker and Zahnle 1986). At that epoch, total eclipses of the Sun would have been more common and visible over a wider region of the Earth’s sur ...
... First, what if the Moon were significantly closer to the Earth? About 2.5 Gyrs ago the Moon’s mean distance from the Earth was about 87% its present value (Walker and Zahnle 1986). At that epoch, total eclipses of the Sun would have been more common and visible over a wider region of the Earth’s sur ...
dtu7ech10sun - Fort Thomas Independent Schools
... It is to become a red giant that will alternately expand and contract in response to variations in inward and outward pressure. At some point, the star will expand and then slowly release its outer gas layer. Up to 80 % ...
... It is to become a red giant that will alternately expand and contract in response to variations in inward and outward pressure. At some point, the star will expand and then slowly release its outer gas layer. Up to 80 % ...
Chapter 11
... 2. Sunspots are about 1,500 K cooler than the surrounding photosphere. Thus they are about 3 times less bright than their surrounding region. 3. The explanation for sunspots involves the Sun’s magnetic field. The strength of this field can be measured using the Zeeman effect (the splitting of spectr ...
... 2. Sunspots are about 1,500 K cooler than the surrounding photosphere. Thus they are about 3 times less bright than their surrounding region. 3. The explanation for sunspots involves the Sun’s magnetic field. The strength of this field can be measured using the Zeeman effect (the splitting of spectr ...
Toys Watch the Sky
... The Sun appears to move from east to west due to the rotation of the Earth in the opposite direction (west to east). The time of day at which shadows are shortest is the time when the Sun is due north, so the shortest shadow points in a north-south direction. Some children may find it hard to believ ...
... The Sun appears to move from east to west due to the rotation of the Earth in the opposite direction (west to east). The time of day at which shadows are shortest is the time when the Sun is due north, so the shortest shadow points in a north-south direction. Some children may find it hard to believ ...
Hands-On Tracking Sunspots!
... The photosphere is a bright layer of the Sun where sunspots form. Sunspots are dark only because they are cooler than the surrounding gases by about 1500 degrees! If you could somehow remove a sunspot and hold it away from the sun, it would glow! Sunspots are huge and can form in groups that are ev ...
... The photosphere is a bright layer of the Sun where sunspots form. Sunspots are dark only because they are cooler than the surrounding gases by about 1500 degrees! If you could somehow remove a sunspot and hold it away from the sun, it would glow! Sunspots are huge and can form in groups that are ev ...
photosphere - Blackboard
... Note that the following lectures include animations and PowerPoint effects such as ...
... Note that the following lectures include animations and PowerPoint effects such as ...
The Sun: Our Star
... The Sun is a star, a fairly common and typical star A star is a ball of gas held in hydrostatic equilibrium against its own self-gravity by the thermal pressure of the hot gas, cooling from center to the surface This energy comes from nuclear fusion reactions at the center of the Sun (we will expand ...
... The Sun is a star, a fairly common and typical star A star is a ball of gas held in hydrostatic equilibrium against its own self-gravity by the thermal pressure of the hot gas, cooling from center to the surface This energy comes from nuclear fusion reactions at the center of the Sun (we will expand ...
teacher resource - Michigan Science Center
... of mostly hydrogen and helium gas with some interstellar dust. Nearby an explosion occurred causing part of the cloud to collapse and become more dense and massive. It eventually grew so massive that it collapsed under its own gravity. This formed a proto-star. This is the first stage of the life cy ...
... of mostly hydrogen and helium gas with some interstellar dust. Nearby an explosion occurred causing part of the cloud to collapse and become more dense and massive. It eventually grew so massive that it collapsed under its own gravity. This formed a proto-star. This is the first stage of the life cy ...
13. Right Ascension and Declination
... For any celestial object, the object’s right ascension plus the object’s current hour angle is equal to the local sidereal time at the observing site. For an object at transit (i.e. H = 0), the local sidereal time equals the object’s right ascension. Equation (14.2) provides the link between the RA- ...
... For any celestial object, the object’s right ascension plus the object’s current hour angle is equal to the local sidereal time at the observing site. For an object at transit (i.e. H = 0), the local sidereal time equals the object’s right ascension. Equation (14.2) provides the link between the RA- ...
Lesson Plan on Kepler`s Laws of Planetary Motion
... 3. Move the pen or pencil around the tacks, keeping the string taut, until you have completed a smooth, closed curve or an ellipse. 4. Repeat Steps 1 though 3 several times. Make note of what happens in each of the following two cases. *****However, change only one of these each time. Note the effec ...
... 3. Move the pen or pencil around the tacks, keeping the string taut, until you have completed a smooth, closed curve or an ellipse. 4. Repeat Steps 1 though 3 several times. Make note of what happens in each of the following two cases. *****However, change only one of these each time. Note the effec ...
Lecture 2 ppt - Physics 1025 Introductory Astronomy
... – Analogous to latitude, but on the celestial sphere; it is the angular north-south distance between the celestial equator and a location on the celestial sphere. – Measured in degrees: » 0 ° to 90 ° – north from celestial equator » 0 ° to -90 ° – south from celestial equator ...
... – Analogous to latitude, but on the celestial sphere; it is the angular north-south distance between the celestial equator and a location on the celestial sphere. – Measured in degrees: » 0 ° to 90 ° – north from celestial equator » 0 ° to -90 ° – south from celestial equator ...
Equations of State for White Dwarfs Elena Heikkilä Kandidaatin
... proportional to the mass, which cannot exceed 1,4 times the Sun’s mass. [9] Greenstein reported on his studies of the spectra of 50 white dwarfs. Some spectra showed prominent helium absorption, others showed dark hydrogen lines and at least one spectra had only the hydrogen and the potassium lines ...
... proportional to the mass, which cannot exceed 1,4 times the Sun’s mass. [9] Greenstein reported on his studies of the spectra of 50 white dwarfs. Some spectra showed prominent helium absorption, others showed dark hydrogen lines and at least one spectra had only the hydrogen and the potassium lines ...
Solar
... become compressed and heated causing it to produce a new surge of power (from the burning of helium into carbon at the core and hydrogen into helium in shells around the core) and begin to swell • This phase is called a red giant and it will ultimately grow so large it will swallow the Earth ...
... become compressed and heated causing it to produce a new surge of power (from the burning of helium into carbon at the core and hydrogen into helium in shells around the core) and begin to swell • This phase is called a red giant and it will ultimately grow so large it will swallow the Earth ...
SU3150-Astronomy - Michigan Technological University
... viewed from zenith Azimuth of a star can have values between 0 and 360 same as azimuth of a survey line Altitude(h) - Angle measured upward (towards zenith) at the center (O) of the celestial sphere, on the plane of the vertical circle through the body, from the horizon to the body Since altitude ...
... viewed from zenith Azimuth of a star can have values between 0 and 360 same as azimuth of a survey line Altitude(h) - Angle measured upward (towards zenith) at the center (O) of the celestial sphere, on the plane of the vertical circle through the body, from the horizon to the body Since altitude ...
Brightness Luminosity and Inverse Square Law
... Sun as viewed from Earth is 1362 W/m2 We also know that Saturn is 9.7 times further away from our Sun than the Earth. If b α 1/d2 , then as viewed from Saturn, the sun would appear 1/(9.7)2 or 1/94th as bright. The brightness would then be 1362 W/m2(1/94) = 14.5 W/m2 ...
... Sun as viewed from Earth is 1362 W/m2 We also know that Saturn is 9.7 times further away from our Sun than the Earth. If b α 1/d2 , then as viewed from Saturn, the sun would appear 1/(9.7)2 or 1/94th as bright. The brightness would then be 1362 W/m2(1/94) = 14.5 W/m2 ...
The Sun
... photosphere. The two outermost layers of the Sun, the chromosphere and the corona, are such thin layers of gas that they can only be seen during a total solar eclipse. The Sun is almost a perfect sphere, which means it has nearly the same radius when measured in any direction from its center. Much l ...
... photosphere. The two outermost layers of the Sun, the chromosphere and the corona, are such thin layers of gas that they can only be seen during a total solar eclipse. The Sun is almost a perfect sphere, which means it has nearly the same radius when measured in any direction from its center. Much l ...
solar cycle
... • Temperature in the corona eventually reaches about 1 million K (not much energy though due to low density) • The corona, visible in a total solar eclipse, can be seen to reach altitudes of several solar radii • The corona is not uniform but has streamers and coronal holes dictated by the Sun’s mag ...
... • Temperature in the corona eventually reaches about 1 million K (not much energy though due to low density) • The corona, visible in a total solar eclipse, can be seen to reach altitudes of several solar radii • The corona is not uniform but has streamers and coronal holes dictated by the Sun’s mag ...
Chapter 11
... • Temperature in the corona eventually reaches about 1 million K (not much energy though due to low density) • The corona, visible in a total solar eclipse, can be seen to reach altitudes of several solar radii • The corona is not uniform but has streamers and coronal holes dictated by the Sun’s mag ...
... • Temperature in the corona eventually reaches about 1 million K (not much energy though due to low density) • The corona, visible in a total solar eclipse, can be seen to reach altitudes of several solar radii • The corona is not uniform but has streamers and coronal holes dictated by the Sun’s mag ...
Apparent Magnitude - RanelaghALevelPhysics
... m. Magnitude 1 stars are about 100 times brighter than magnitude 6 stars. A change in 1 magnitude is a change of 2.512 (1001/5 = 2.512). The scale is logarithmic because each step corresponds to multiplying by a constant ...
... m. Magnitude 1 stars are about 100 times brighter than magnitude 6 stars. A change in 1 magnitude is a change of 2.512 (1001/5 = 2.512). The scale is logarithmic because each step corresponds to multiplying by a constant ...
The Sun
... This diagram illustrates how the Sun's differential rotation wraps and distorts the solar magnetic field. Occasionally, the field lines burst out of the surface and loop through the lower atmosphere, thereby creating a sunspot ...
... This diagram illustrates how the Sun's differential rotation wraps and distorts the solar magnetic field. Occasionally, the field lines burst out of the surface and loop through the lower atmosphere, thereby creating a sunspot ...
The Sun
... •The solar rotation period is found by timing sunspots and other surface features as they traverse across the sun •These observations indicate that the Sun rotates in about a month, but it does not do so as a solid body. •Instead, it spins differentially—faster at the equator and slower at the poles ...
... •The solar rotation period is found by timing sunspots and other surface features as they traverse across the sun •These observations indicate that the Sun rotates in about a month, but it does not do so as a solid body. •Instead, it spins differentially—faster at the equator and slower at the poles ...
Coordinate Systems for Astronomy or: How to get
... on the Greenwich Meridian. The world is divided into Time Zones; 15 degrees change in longitude is equivalent to an hour's change in time. South Africa is roughly 30 degrees east of Greenwich, and so South African Standard Time (SAST) is set to be 2 hours ahead of UTC. Our “year” is technically the ...
... on the Greenwich Meridian. The world is divided into Time Zones; 15 degrees change in longitude is equivalent to an hour's change in time. South Africa is roughly 30 degrees east of Greenwich, and so South African Standard Time (SAST) is set to be 2 hours ahead of UTC. Our “year” is technically the ...
The Sun Video Focus Questions
... sun completely runs out of hydrogen, it will shrink down to about half the size of our moon (gravity will make it collapse), but will still give off a white glow. This is known as the White Dwarf phase. Finally, the sun will cool into a dark, dead star. 15. Nuclear fusion takes place in the core of ...
... sun completely runs out of hydrogen, it will shrink down to about half the size of our moon (gravity will make it collapse), but will still give off a white glow. This is known as the White Dwarf phase. Finally, the sun will cool into a dark, dead star. 15. Nuclear fusion takes place in the core of ...
Equation of time
The equation of time describes the discrepancy between two kinds of solar time. These are apparent solar time, which directly tracks the motion of the sun, and mean solar time, which tracks a fictitious ""mean"" sun with noons 24 hours apart. Apparent (or true) solar time can be obtained by measurement of the current position (hour angle) of the Sun, or indicated (with limited accuracy) by a sundial. Mean solar time, for the same place, would be the time indicated by a steady clock set so that over the year its differences from apparent solar time average to zero.The equation of time is the east or west component of the analemma, a curve representing the angular offset of the Sun from its mean position on the celestial sphere as viewed from Earth. The equation of time values for each day of the year, compiled by astronomical observatories, were widely listed in almanacs and ephemerides.