The Morphology of Galaxy Clusters
... to virialize: the virialization time for galaxy superclusters—about 1010.5 yr—is longer than the Hubble time. In contrast, the virialization time for galaxy clusters is about 109 yr, i.e. less than the Hubble time. At the same time, on the scale of galaxy clusters the components have not yet had a c ...
... to virialize: the virialization time for galaxy superclusters—about 1010.5 yr—is longer than the Hubble time. In contrast, the virialization time for galaxy clusters is about 109 yr, i.e. less than the Hubble time. At the same time, on the scale of galaxy clusters the components have not yet had a c ...
giant molecular clouds
... • What evidence do astronomers have that theories of star formation are correct? ...
... • What evidence do astronomers have that theories of star formation are correct? ...
Soal Short
... 6. Radio wavelength observations of gas cloud swirling around a black hole in the center of our galaxy show that radiation from the hydrogen spin-flip transition (rest frequency = 1420.41 MHz) is detected at a frequency of 1421.23 MHz. If this gas cloud is located at a distance of 0.2 pc from the bl ...
... 6. Radio wavelength observations of gas cloud swirling around a black hole in the center of our galaxy show that radiation from the hydrogen spin-flip transition (rest frequency = 1420.41 MHz) is detected at a frequency of 1421.23 MHz. If this gas cloud is located at a distance of 0.2 pc from the bl ...
The Formation of Stars Chapter 11 Guidepost Guidepost
... • What evidence do astronomers have that theories of star formation are correct? ...
... • What evidence do astronomers have that theories of star formation are correct? ...
Star Counts Lab
... sky,” but how many is that? In this lab you will make an estimate of how many stars you could see if you could see the entire sky with your naked eye. It would not be possible to count all the stars visible in the sky during a single lab meeting. For one reason, the number is very large; for another ...
... sky,” but how many is that? In this lab you will make an estimate of how many stars you could see if you could see the entire sky with your naked eye. It would not be possible to count all the stars visible in the sky during a single lab meeting. For one reason, the number is very large; for another ...
Document
... The Habitable Zone When we look at other star systems, one of the first things we look for is what’s called the “habitable zone”. This is the area in the star system where you’d be just the right distance for water to be liquid. Why? Because it might mean a planet like Earth that we could someday c ...
... The Habitable Zone When we look at other star systems, one of the first things we look for is what’s called the “habitable zone”. This is the area in the star system where you’d be just the right distance for water to be liquid. Why? Because it might mean a planet like Earth that we could someday c ...
Rotation in the ZAMS: Be and Bn stars
... Figure 3a shows the apparent V=7 magnitude limited counts of dwarf Be stars relative to dwarf B stars. There is an apparent lack of dwarf Be stars cooler than spectral type B7. This could be due to genuine Be stars whose discs are minute and/or too cool for the Hα emission be detectable and/or, to f ...
... Figure 3a shows the apparent V=7 magnitude limited counts of dwarf Be stars relative to dwarf B stars. There is an apparent lack of dwarf Be stars cooler than spectral type B7. This could be due to genuine Be stars whose discs are minute and/or too cool for the Hα emission be detectable and/or, to f ...
Astronomy Astrophysics Massive open star clusters using the VVV survey &
... Aims. We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVV CL086, using part of its OB-stellar population. Methods. We physically characterized the cluster using JHKS n ...
... Aims. We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVV CL086, using part of its OB-stellar population. Methods. We physically characterized the cluster using JHKS n ...
Document
... stars, gas, and dust • The remaining 90% is in some nonvisible form, called dark matter, that extends beyond the edge of the luminous material in the Galaxy • Our Galaxy’s dark matter may be a combination of MACHOs (dim, star-sized objects), massive neutrinos, and WIMPs (relatively massive subatomic ...
... stars, gas, and dust • The remaining 90% is in some nonvisible form, called dark matter, that extends beyond the edge of the luminous material in the Galaxy • Our Galaxy’s dark matter may be a combination of MACHOs (dim, star-sized objects), massive neutrinos, and WIMPs (relatively massive subatomic ...
Stars and Planets - The University of Texas at Dallas
... The Pleiades is a famous cluster of young stars visible in the constellation Taurus. When most of the gas and dust is gone from a stellar nursery, the young stars are in an open cluster. One day these star systems will drift apart. Image source: http://antwrp.gsfc.nasa.gov/apod/ap021201.html ...
... The Pleiades is a famous cluster of young stars visible in the constellation Taurus. When most of the gas and dust is gone from a stellar nursery, the young stars are in an open cluster. One day these star systems will drift apart. Image source: http://antwrp.gsfc.nasa.gov/apod/ap021201.html ...
History of Star Formation in Local Galaxies
... pause due to reionization (12.6 Gyr, z ≈ 6), but each has a seemingly unique star formation history extending over many Gyr. Why? Differences in DM halo masses, differences in continued infall, tidal forces, stripping? Do the SFHs derived match those predicted by ΛCMD? Lets compare with simulation ...
... pause due to reionization (12.6 Gyr, z ≈ 6), but each has a seemingly unique star formation history extending over many Gyr. Why? Differences in DM halo masses, differences in continued infall, tidal forces, stripping? Do the SFHs derived match those predicted by ΛCMD? Lets compare with simulation ...
ISP205L, Week 13 Computer Lab Activity The Distance to the Pleiades
... that the luminosity is the total energy per unit time emitted in all directions by the star, while the flux is the energy per unit time per unit surface area that reaches an observer at a distance d from the star. The relation between flux and luminosity is L ...
... that the luminosity is the total energy per unit time emitted in all directions by the star, while the flux is the energy per unit time per unit surface area that reaches an observer at a distance d from the star. The relation between flux and luminosity is L ...
Stars and Galaxies
... is spun from just a few spoonfuls of sugar. Cotton candy is mostly air. Similarly, atoms are mostly empty space. During a supernova, the collapse is so violent that it eliminates the normal spaces inside atoms, and a neutron star forms. A neutron star is a dense core of neutrons that remains after a ...
... is spun from just a few spoonfuls of sugar. Cotton candy is mostly air. Similarly, atoms are mostly empty space. During a supernova, the collapse is so violent that it eliminates the normal spaces inside atoms, and a neutron star forms. A neutron star is a dense core of neutrons that remains after a ...
Spiral structure of the Third Galactic Quadrant and the solution to the
... Martı́nez-Delgado et al. 2005). Although the CMDs do not exhibit clear post main-sequence signatures expected for a 4-10 Gyr population (Martı́nez-Delgado et al. 2005) (red clump or red giant branch, horizontal branch, RR-Lyrae), a distinctive feature, popularised as the Blue Plume (BP; see Fig. 1) ...
... Martı́nez-Delgado et al. 2005). Although the CMDs do not exhibit clear post main-sequence signatures expected for a 4-10 Gyr population (Martı́nez-Delgado et al. 2005) (red clump or red giant branch, horizontal branch, RR-Lyrae), a distinctive feature, popularised as the Blue Plume (BP; see Fig. 1) ...
dark matter - University of Texas Astronomy Home Page
... 2. At right is a picture of a spiral galaxy similar to the Milky Way. The orbits of three stars are labeled. Star A is on the edge of the bulge. The Sun’s orbit is marked by Star B and Star C is farther out in the disk than the Sun. Which star do you think is traveling fastest and which is traveling ...
... 2. At right is a picture of a spiral galaxy similar to the Milky Way. The orbits of three stars are labeled. Star A is on the edge of the bulge. The Sun’s orbit is marked by Star B and Star C is farther out in the disk than the Sun. Which star do you think is traveling fastest and which is traveling ...
star-formation rate
... q is the ratio of the mass in metals, which is produced by a stellar population and then returned into the ISM, and the initial total mass of the population. The yield y = q/α is defined as the ratio of the mass in metals that is produced by a stellar population and returned into the ISM, and the ma ...
... q is the ratio of the mass in metals, which is produced by a stellar population and then returned into the ISM, and the initial total mass of the population. The yield y = q/α is defined as the ratio of the mass in metals that is produced by a stellar population and returned into the ISM, and the ma ...
Using a distant X-ray source to detect small Transneptunian Objects
... Depending on the position of the Earth in its orbit over the 6 years of the observations, the angular speed of the Earth relative to the TNO is sometimes added and sometimes subtracted. What is the maximum blocking time for the signals which could be expected from a spherical TNO with a 100 m diamet ...
... Depending on the position of the Earth in its orbit over the 6 years of the observations, the angular speed of the Earth relative to the TNO is sometimes added and sometimes subtracted. What is the maximum blocking time for the signals which could be expected from a spherical TNO with a 100 m diamet ...
28.2 Calculating Luminosity
... You have learned that in order to understand stars, astronomers want to know their luminosity. Luminosity describes how much light is coming from the star each second. Luminosity can be measured in watts (W). Measuring the luminosity of something as far away as a star is difficult to do. However, we ...
... You have learned that in order to understand stars, astronomers want to know their luminosity. Luminosity describes how much light is coming from the star each second. Luminosity can be measured in watts (W). Measuring the luminosity of something as far away as a star is difficult to do. However, we ...
Stellar Relaxation Times
... center of the Galaxy is not gravitationally affected by other stars. On the other hand, giant molecular clouds have masses that are ~ 108 M. Although the number density of clouds is lower, it’s not 1016 times lower! The masses of these clouds are therefore high enough to scatter stars out of their ...
... center of the Galaxy is not gravitationally affected by other stars. On the other hand, giant molecular clouds have masses that are ~ 108 M. Although the number density of clouds is lower, it’s not 1016 times lower! The masses of these clouds are therefore high enough to scatter stars out of their ...
How the Universe reveals itself
... and heat from a star. With these prerequisites in mind, the search for life elsewhere is presently focused on discovering planets around other stars. Finding extra-solar planets (planets outside the solar system, also called exoplanets) is a very challenging task. Firstly, even the nearest stars are ...
... and heat from a star. With these prerequisites in mind, the search for life elsewhere is presently focused on discovering planets around other stars. Finding extra-solar planets (planets outside the solar system, also called exoplanets) is a very challenging task. Firstly, even the nearest stars are ...
In Pictures: Journey to the Stars
... the size of the Universe. It’s so big that light from the most distant galaxies takes over 10 billion years just to reach us on Earth! That’s twice as long as Earth’s been around. Everything we’ve ever observed in space is part of our Universe. We don’t know what’s beyond it or if there are other Un ...
... the size of the Universe. It’s so big that light from the most distant galaxies takes over 10 billion years just to reach us on Earth! That’s twice as long as Earth’s been around. Everything we’ve ever observed in space is part of our Universe. We don’t know what’s beyond it or if there are other Un ...
Unresolved Stellar Populations
... age t, Φ(M )dM is the IMF (assumed to be the Salpeter IMF here). while Ml and Mu are the lower and upper limit to the mass of the stars. The choice of Ml , as long as sufficiently small, should not affect significantly the value of Fλ , whereas Mu is not an independent parameter and is the function ...
... age t, Φ(M )dM is the IMF (assumed to be the Salpeter IMF here). while Ml and Mu are the lower and upper limit to the mass of the stars. The choice of Ml , as long as sufficiently small, should not affect significantly the value of Fλ , whereas Mu is not an independent parameter and is the function ...
PH607lec12
... of the Universe. On average, the smaller galaxies have one-tenth the mass of the larger ones, and are only about half their age. The term 'downsizing' essentially means that when the Universe was relatively young, the star formation activity occurred in large galaxies, but as the Universe aged, the ...
... of the Universe. On average, the smaller galaxies have one-tenth the mass of the larger ones, and are only about half their age. The term 'downsizing' essentially means that when the Universe was relatively young, the star formation activity occurred in large galaxies, but as the Universe aged, the ...
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.