c. From (2009) --
... At the center of the Milky Way there is a mysterious radio source Saggitarius A * (Sgr A *). Scientists have observed stars to orbit Sgr A * with surprisingly high velocities. One of these stars, S2, at its closest approach to Sgr A * of 17 light-hours, was moving at 5000 km S-l! By combining measur ...
... At the center of the Milky Way there is a mysterious radio source Saggitarius A * (Sgr A *). Scientists have observed stars to orbit Sgr A * with surprisingly high velocities. One of these stars, S2, at its closest approach to Sgr A * of 17 light-hours, was moving at 5000 km S-l! By combining measur ...
Document
... • Measure the observed brightness • Compare the observed brightness with the luminosity to work out the distance ...
... • Measure the observed brightness • Compare the observed brightness with the luminosity to work out the distance ...
The Luminosity
... dimming with distance • A star’s apparent brightness depends on its distance • The light spreads out uniformly in all directions over a sphere whose radius is the distance. • Surface area of a sphere = 4 π R2 • The star’s apparent brightness will depend on intrinsic luminosity L, and distance fr ...
... dimming with distance • A star’s apparent brightness depends on its distance • The light spreads out uniformly in all directions over a sphere whose radius is the distance. • Surface area of a sphere = 4 π R2 • The star’s apparent brightness will depend on intrinsic luminosity L, and distance fr ...
2017 MIT Invitational
... 13. A star with the same absolute magnitude of the Sun has a parallax of 0.01”. The H-α line of this star is measured to be 6565.8 Angstroms. The H-α wavelength is expected to be at 6562.8 Angstroms based on laboratory measurements. (a) What is the distance to this star, in parsecs? (b) What is the ...
... 13. A star with the same absolute magnitude of the Sun has a parallax of 0.01”. The H-α line of this star is measured to be 6565.8 Angstroms. The H-α wavelength is expected to be at 6562.8 Angstroms based on laboratory measurements. (a) What is the distance to this star, in parsecs? (b) What is the ...
Parallax - mjeffries
... • How can the measurement of the triangle be improved? 1. Make the base larger. 2. Measure the angle more accurately. ...
... • How can the measurement of the triangle be improved? 1. Make the base larger. 2. Measure the angle more accurately. ...
Evolution of a Low-Mass Star
... Why are stars different colors? They are different Temperatures! Recall – maximum intensity of radiated E-M waves depends on Temperature. So Astronomers can measure the apparent brightness of a star at several intensities (“colors”) to determine the temperature. ...
... Why are stars different colors? They are different Temperatures! Recall – maximum intensity of radiated E-M waves depends on Temperature. So Astronomers can measure the apparent brightness of a star at several intensities (“colors”) to determine the temperature. ...
The Milky Way: Home to Star Clusters
... by feeding model and implies that most, if not all, halo stars evolved at the same or similar time. To complicate matters further, other studies appear to show that the chemical content of lone and cluster stars within the halo are different to those in dwarf galaxies, further disproving the canniba ...
... by feeding model and implies that most, if not all, halo stars evolved at the same or similar time. To complicate matters further, other studies appear to show that the chemical content of lone and cluster stars within the halo are different to those in dwarf galaxies, further disproving the canniba ...
Properties of Stars - Indiana State University
... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
Lecture Ten - The Sun Amongst the Stars Part II
... So why are there so many M dwarfs? Does the star formation process strongly favor the production of such stars? Or is there some other process at work ‘removing’ hotter and more luminous stars from the populations we observe? The answer requires us to know how stars change over time, and therefore t ...
... So why are there so many M dwarfs? Does the star formation process strongly favor the production of such stars? Or is there some other process at work ‘removing’ hotter and more luminous stars from the populations we observe? The answer requires us to know how stars change over time, and therefore t ...
PH607lec12
... Because of cool interstellar dust along the line of sight, the Galactic Centre cannot be studied at visible, ultraviolet or soft Xray wavelengths. The available information about the Galactic Center comes from observations at gamma ray, hard X-ray, infrared, sub-millimetre and radio wavelengths. ...
... Because of cool interstellar dust along the line of sight, the Galactic Centre cannot be studied at visible, ultraviolet or soft Xray wavelengths. The available information about the Galactic Center comes from observations at gamma ray, hard X-ray, infrared, sub-millimetre and radio wavelengths. ...
What we can measure
... and watch one orbit the other. These are called visual binaries. We need to be careful here, since some stars only appear to be close due to our perspective. These are called “optical doubles” and not real binary systems at all. We can tell the difference by watching these over time or by noting tha ...
... and watch one orbit the other. These are called visual binaries. We need to be careful here, since some stars only appear to be close due to our perspective. These are called “optical doubles” and not real binary systems at all. We can tell the difference by watching these over time or by noting tha ...
Chapter 13 (Properties of Stars)
... 17. The song written by Jane Taylor has the lyrics "Twinkle, twinkle little star, How I wonder what you are." Why is it that when we view stars with our naked eye, they seem to twinkle? A. The effect is caused by Earth's atmospheric changes. B. Rapid motion of sunspots causes it C. It depends on the ...
... 17. The song written by Jane Taylor has the lyrics "Twinkle, twinkle little star, How I wonder what you are." Why is it that when we view stars with our naked eye, they seem to twinkle? A. The effect is caused by Earth's atmospheric changes. B. Rapid motion of sunspots causes it C. It depends on the ...
Doppler Effect - SAVE MY EXAMS!
... would be detected from a source approaching the observer at a speed of 105 km s–1. wavelength of atomic hydrogen measured in a laboratory = 0.21121 m. ...
... would be detected from a source approaching the observer at a speed of 105 km s–1. wavelength of atomic hydrogen measured in a laboratory = 0.21121 m. ...
Section2_Coordinates.. - Faculty Web Sites at the University of Virginia
... Solar System as a whole. Stars in this system have positions determined with respect to observed positions of planets. Observations made with meridian circles contribute to the establishment of this type of reference frame (FK3, FK4, FK5 systems). ...
... Solar System as a whole. Stars in this system have positions determined with respect to observed positions of planets. Observations made with meridian circles contribute to the establishment of this type of reference frame (FK3, FK4, FK5 systems). ...
Lecture02-ASTA01 - University of Toronto
... (wavelengths longer than visible red) and UV means ultraviolet (wavelengths shorter than visible violet. • Separate colors are often denoted: U B V R I (ultraviolet, blue, visible yellow-green, red, near ...
... (wavelengths longer than visible red) and UV means ultraviolet (wavelengths shorter than visible violet. • Separate colors are often denoted: U B V R I (ultraviolet, blue, visible yellow-green, red, near ...
Galaxies Galore
... Go to p. 7 links: Galaxies – Planetquest (http://planetquest.jpl.nasa.gov/interactives) Scroll down to “3D Guide to the Galaxy” Click on: Launch Interactive (You may want to Mute sound) 1. “How Big? “ If our solar system were the size of a quarter, the galaxy would be __________. 2. How large is the ...
... Go to p. 7 links: Galaxies – Planetquest (http://planetquest.jpl.nasa.gov/interactives) Scroll down to “3D Guide to the Galaxy” Click on: Launch Interactive (You may want to Mute sound) 1. “How Big? “ If our solar system were the size of a quarter, the galaxy would be __________. 2. How large is the ...
A Universe of Galaxies - Pennsylvania State University
... What can outshine ~1000 supernovae for millions of years, and be just slightly larger than our Solar System? Theoretically, not much – only a very, very big black hole. • Start with a black hole with a mass of 10,000,000,000 Mʘ • Have a star come close enough to be tidally disrupted • Have the mater ...
... What can outshine ~1000 supernovae for millions of years, and be just slightly larger than our Solar System? Theoretically, not much – only a very, very big black hole. • Start with a black hole with a mass of 10,000,000,000 Mʘ • Have a star come close enough to be tidally disrupted • Have the mater ...
Our Universe is big, beautiful… and mostly
... Although dark matter is invisible, astronomers can work out where it is in space from the effect that it has on the things around it – like seeing a sofa cushion being pushed down by an invisible man. In this picture, anywhere containing matter – both visible and invisible stuff – has been coloured in ...
... Although dark matter is invisible, astronomers can work out where it is in space from the effect that it has on the things around it – like seeing a sofa cushion being pushed down by an invisible man. In this picture, anywhere containing matter – both visible and invisible stuff – has been coloured in ...
Slide 1
... star's outer regions expand due to this new energy input. As the emitting surface area of the star's photosphere increases so does its apparent brightness, also as it expands the photosphere cools (as it becomes cooler, the colour of the star becomes redder). The star thus moves up and to the right ...
... star's outer regions expand due to this new energy input. As the emitting surface area of the star's photosphere increases so does its apparent brightness, also as it expands the photosphere cools (as it becomes cooler, the colour of the star becomes redder). The star thus moves up and to the right ...
the solar neighborhood. xi. the trigonometric parallax of scr
... bright stars were selected as local astrometric reference stars. These reference stars were used to fit linear models for each of the plates with respect to the array of mean reference star positions. The residual errors from the reference stars after these models are applied give an indication of t ...
... bright stars were selected as local astrometric reference stars. These reference stars were used to fit linear models for each of the plates with respect to the array of mean reference star positions. The residual errors from the reference stars after these models are applied give an indication of t ...
Stars: Binary Systems
... The two curves ( one for each star ) are sinusoidal and oscillate with exactly opposite phase ( one star approaches as the other recedes ). The amplitude of each velocity curve yields r1 and r2. The star with the largest velocity amplitude has the largest radius, and hence the smallest mass. ...
... The two curves ( one for each star ) are sinusoidal and oscillate with exactly opposite phase ( one star approaches as the other recedes ). The amplitude of each velocity curve yields r1 and r2. The star with the largest velocity amplitude has the largest radius, and hence the smallest mass. ...
Triangulation Trigonometric Parallax
... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
... – Superimposed on this orbital motion are small random motions of about 20 km/sec – In addition to their motion through space, stars spin on their axes and this spin can be measured using the Doppler shift technique – young stars are found to rotate faster than old stars ...
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.