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Astronomical Distance Determination • etc.
... corresponds to 53 AU/yr. Most of the nearby stars are moving along with us, but not precisely. Barnards star moves 10.25 arc sec per year and hundreds of other stars move over 1 arc sec per year. The suns average drift over a number of years compared with the local average, gives a longer baseline ...
... corresponds to 53 AU/yr. Most of the nearby stars are moving along with us, but not precisely. Barnards star moves 10.25 arc sec per year and hundreds of other stars move over 1 arc sec per year. The suns average drift over a number of years compared with the local average, gives a longer baseline ...
Monday, April 15
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
... • Then do the following Gedankenexperiment: – In your mind, put the star from its actual position to a position 10 pc away – If a star is actually closer than 10pc, its absolute magnitude will be a bigger number, i.e. it is intrinsically dimmer than it appears – If a star is farther than 10pc, its a ...
Distance - courses.psu.edu
... Luminosity: total amount of energy radiated per second (“wattage”) Watt? Watt? ...
... Luminosity: total amount of energy radiated per second (“wattage”) Watt? Watt? ...
Science 9 Unit 5: Space Name:
... Adaptive opticsAdaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of wave front distortions TriangulationFormation of or division into triangles. ParallaxThe effect whereby the position or direction of an object appears to differ when viewe ...
... Adaptive opticsAdaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of wave front distortions TriangulationFormation of or division into triangles. ParallaxThe effect whereby the position or direction of an object appears to differ when viewe ...
Lecture 6: Stellar Distances and Brightness
... If stars are too far away, the parallax will be too small to measure accurately The smallest parallax measureable from the ground is about 0.01 arcsec Measure distances out to ~100 pc Get 10% distances only to a few parsecs But there are only a few hundred stars this close, so the errors are much bi ...
... If stars are too far away, the parallax will be too small to measure accurately The smallest parallax measureable from the ground is about 0.01 arcsec Measure distances out to ~100 pc Get 10% distances only to a few parsecs But there are only a few hundred stars this close, so the errors are much bi ...
Answer to question 1 - Northwestern University
... • What limits the accuracy of my measurement? • How will I calibrate my measurements so that somebody else can judge the results. • What assumptions will I have to make from theory or experiment to build my case. • If I’m looking for an effect (such as WIMPs), will my result be interesting even if I ...
... • What limits the accuracy of my measurement? • How will I calibrate my measurements so that somebody else can judge the results. • What assumptions will I have to make from theory or experiment to build my case. • If I’m looking for an effect (such as WIMPs), will my result be interesting even if I ...
Spectroscopic parallax
... variable's luminosity and variability period is quite precise, and has been used as a standard candle (astronomical object that has a know luminosity) for almost a century. This connection was discovered in 1912 by ...
... variable's luminosity and variability period is quite precise, and has been used as a standard candle (astronomical object that has a know luminosity) for almost a century. This connection was discovered in 1912 by ...
The Sun: Home Star
... • Key to solar-stellar connection • Close-up model for other stars • Local “lab” for testing ideas about the physics of stars • Energy source for most life on earth ...
... • Key to solar-stellar connection • Close-up model for other stars • Local “lab” for testing ideas about the physics of stars • Energy source for most life on earth ...
The Hot-plate Model of a Star Model of Stars— 3 Oct
... Brightest stars on top An increase of 2.5 magnitudes ⇒ star is a factor of 10 fainter. ...
... Brightest stars on top An increase of 2.5 magnitudes ⇒ star is a factor of 10 fainter. ...
The cosmic distance scale
... circular orbits, but has some random motion, whose effect is to broaden the observed lines. This can be estimated to be typically 10 km/s. The second effect is due to the inclination. The width that we measure is essentially 2 Vc sin i. Therefore, the quantity WR = (W20- Wrand)/sin i is an inclinati ...
... circular orbits, but has some random motion, whose effect is to broaden the observed lines. This can be estimated to be typically 10 km/s. The second effect is due to the inclination. The width that we measure is essentially 2 Vc sin i. Therefore, the quantity WR = (W20- Wrand)/sin i is an inclinati ...
WK7
... A change in apparent magnitude by 5 corresponds to an increase in apparent brightness by a factor of ...
... A change in apparent magnitude by 5 corresponds to an increase in apparent brightness by a factor of ...
The Danger of Deadly Cosmic Explosions
... – Brighter than a galaxy for a few days – More radiation than during whole life of star ...
... – Brighter than a galaxy for a few days – More radiation than during whole life of star ...
Ast 405, Pulsating Stars The following is based Chapter 14 of the
... • 1. Stars whose brightness varies regularly due to some internal mechanism. • 2. Examples are Miras, Cepheids, RR Lyraes, W Virginis, BL Her stars. You shouyld be familiar with Table 14.1 in the book. • 3. The Cepheid Period-Luminosity relation, or PL relation is of crucial importance in Astrophysi ...
... • 1. Stars whose brightness varies regularly due to some internal mechanism. • 2. Examples are Miras, Cepheids, RR Lyraes, W Virginis, BL Her stars. You shouyld be familiar with Table 14.1 in the book. • 3. The Cepheid Period-Luminosity relation, or PL relation is of crucial importance in Astrophysi ...
Cosmology Fact Sheet
... We only know the distance to certain objects in the universe, and even that isn’t very accurate. Parallax measurements using the Earth’s orbit as a baseline allow us to find the distance to stars in our own galaxy quite well. Distances longer than this are no good though. However, if you measure the ...
... We only know the distance to certain objects in the universe, and even that isn’t very accurate. Parallax measurements using the Earth’s orbit as a baseline allow us to find the distance to stars in our own galaxy quite well. Distances longer than this are no good though. However, if you measure the ...
Astronomy Toolkit
... six different brightness classes called magnitudes • Hipparcos chose to categorize the brightest stars as magnitude 1, and the faintest as magnitude 6 (smaller numbers are brighter stars) • The magnitude system of Hipparcos is still in use today in a slightly revised form ...
... six different brightness classes called magnitudes • Hipparcos chose to categorize the brightest stars as magnitude 1, and the faintest as magnitude 6 (smaller numbers are brighter stars) • The magnitude system of Hipparcos is still in use today in a slightly revised form ...
Solutions to test #2 taken on Tuesday
... 2. (15) Millions, Billions or One. This is an “order of magnitude” question. Pick the number (the order of magnitude) that is closest for each. a) _millions_The temperature in the core of the Sun. b) ___one__ The size of a typical black hole’s event horizon (in kilometers) created in the death of a ...
... 2. (15) Millions, Billions or One. This is an “order of magnitude” question. Pick the number (the order of magnitude) that is closest for each. a) _millions_The temperature in the core of the Sun. b) ___one__ The size of a typical black hole’s event horizon (in kilometers) created in the death of a ...
Module 6: “The Message of Starlight Assignment 9: Parallax, stellar
... temperatures, then their intrinsic brightness are different. By intrinsic brightness we mean how bright they are, independent of their distance. So let’s see how we can determine this. We want to know if stars are all the same, or different, intrinsic brightness. But unless we know the distance of a ...
... temperatures, then their intrinsic brightness are different. By intrinsic brightness we mean how bright they are, independent of their distance. So let’s see how we can determine this. We want to know if stars are all the same, or different, intrinsic brightness. But unless we know the distance of a ...
Nov 2009
... On the axes of the Hertzsprung–Russell diagram above, draw the approximate region in which Cepheid variable stars are located. ...
... On the axes of the Hertzsprung–Russell diagram above, draw the approximate region in which Cepheid variable stars are located. ...
Jeopardy Questions
... Q: What is the period-luminosity relationship A: An observed relationship between the period of a Cepheid Variable star’s variability and its luminosity. This relation enabled accurate distances to stars in the Milky Way to be measured for the first time ...
... Q: What is the period-luminosity relationship A: An observed relationship between the period of a Cepheid Variable star’s variability and its luminosity. This relation enabled accurate distances to stars in the Milky Way to be measured for the first time ...
labex7
... 4. From the absolute magnitude that you found for each star determine the star’s luminosity in solar units. (Hint – the absolute magnitude of the Sun is 4.84. Polaris has an absolute magnitude of -3.66. This means that Polaris is 4.84 - (-3.66) = 8.5 magnitudes brighter than the Sun. Use the magnitu ...
... 4. From the absolute magnitude that you found for each star determine the star’s luminosity in solar units. (Hint – the absolute magnitude of the Sun is 4.84. Polaris has an absolute magnitude of -3.66. This means that Polaris is 4.84 - (-3.66) = 8.5 magnitudes brighter than the Sun. Use the magnitu ...
The Inverse Square Law and Surface Area
... stars and classify their power output and compare them with more distant stars The following very bright objects of known luminosity can be identified in distant galaxies • Cepheid Variable Stars ...
... stars and classify their power output and compare them with more distant stars The following very bright objects of known luminosity can be identified in distant galaxies • Cepheid Variable Stars ...
Scale of Apparent Magnitudes of Celestial Objects
... The creator of the system for measuring the apparent brightness of stars is believed to be Hipparchus, who lived in Nicaea (Turkey) during the second century BCE. Hipparchus is believed by many to be the greatest of the ancient astronomers. The original scale of apparent magnitude gave the brightest ...
... The creator of the system for measuring the apparent brightness of stars is believed to be Hipparchus, who lived in Nicaea (Turkey) during the second century BCE. Hipparchus is believed by many to be the greatest of the ancient astronomers. The original scale of apparent magnitude gave the brightest ...
Cosmic distance ladder
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are ""close enough"" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.The ladder analogy arises because no one technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.