Superwind - The University of Sydney
... they are driven by minute dust grains, which form in the atmosphere of the star and absorb its light. The star light pushes the dust grains (silicates) away from the star. However, models show that this mechanism does not work well. The dust grains become too hot, and evaporate before they can be pu ...
... they are driven by minute dust grains, which form in the atmosphere of the star and absorb its light. The star light pushes the dust grains (silicates) away from the star. However, models show that this mechanism does not work well. The dust grains become too hot, and evaporate before they can be pu ...
The Hidden Lives of Galaxies NSTA 2001
... Helium formed. • At t =1 s, T=10,000,000,000 K: soup of particles: photons, electrons, positrons, protons, neutrons. Particles created & destroyed. • At t =3 min, T=1,000,000,000 K: p+n => D ...
... Helium formed. • At t =1 s, T=10,000,000,000 K: soup of particles: photons, electrons, positrons, protons, neutrons. Particles created & destroyed. • At t =3 min, T=1,000,000,000 K: p+n => D ...
Low-Mass Stars
... • Core radius = Diameter of Earth! • Pressure and temperature great enough for the Helium Flash! 3He C + Energy ...
... • Core radius = Diameter of Earth! • Pressure and temperature great enough for the Helium Flash! 3He C + Energy ...
Stars - Moodle
... • Astronomers analyze stars by looking at the light they emit • They use a spectrograph • A spectrograph separates light into different colors or wavelengths • Stars produce a display of colors and lines called a spectrum ...
... • Astronomers analyze stars by looking at the light they emit • They use a spectrograph • A spectrograph separates light into different colors or wavelengths • Stars produce a display of colors and lines called a spectrum ...
Stellar Evolution
... • Core radius = Diameter of Earth! • Pressure and temperature great enough for the Helium Flash! 3He C + Energy ...
... • Core radius = Diameter of Earth! • Pressure and temperature great enough for the Helium Flash! 3He C + Energy ...
Measuring the Stars
... Stellar spectra are much more informative than the blackbody curves. There are seven general categories of stellar spectra, corresponding to different ...
... Stellar spectra are much more informative than the blackbody curves. There are seven general categories of stellar spectra, corresponding to different ...
17Nov_2014
... • All Type 1a supernova have similar peak luminosities, and so can be used to measure the distance to the clusters or galaxies that contain them! ...
... • All Type 1a supernova have similar peak luminosities, and so can be used to measure the distance to the clusters or galaxies that contain them! ...
April
... as the Black Eye Galaxy, this object has a diameter of about 51,000 LY. Steady seeing will offer viewers a bright irregular shape with uneven brightness and texture. This is as a result of an unusual characteristic: the central portion of the galaxy rotates in one direction out to approximately 3,00 ...
... as the Black Eye Galaxy, this object has a diameter of about 51,000 LY. Steady seeing will offer viewers a bright irregular shape with uneven brightness and texture. This is as a result of an unusual characteristic: the central portion of the galaxy rotates in one direction out to approximately 3,00 ...
Extraterrestrial Life
... Np – number of planets around stars like Sun Fs – fraction of stars with properties for life to develop • Water is probably essential as a solvent. So, planet must have exact temperature (distance from the star) to have water (liquid state). Between 273 K and 373 K. • Pressure must be right too (atm ...
... Np – number of planets around stars like Sun Fs – fraction of stars with properties for life to develop • Water is probably essential as a solvent. So, planet must have exact temperature (distance from the star) to have water (liquid state). Between 273 K and 373 K. • Pressure must be right too (atm ...
Candles in the Dark
... “M31 and other nebulae were galaxies of many billions of stars” we could use how much dimmer a star appears than the Sun to calculate how far away it is. In fact, the great William Herschel tried to use this idea to give a relative scale to the galaxy a couple of decades before parallax was successf ...
... “M31 and other nebulae were galaxies of many billions of stars” we could use how much dimmer a star appears than the Sun to calculate how far away it is. In fact, the great William Herschel tried to use this idea to give a relative scale to the galaxy a couple of decades before parallax was successf ...
THE CONSTELLATION LUPUS, THE WOLF
... ages of man: Golden, Silver, Brazen, and Iron (the present age). In the Iron Age men become evil, greedy and dishonest. Zeus/Jupiter tells the assembled gods on Mount Olympus that he must punish these men and proceeds to tell them how he dealt with an especially corrupt man, Lycaon, king of Arcadia, ...
... ages of man: Golden, Silver, Brazen, and Iron (the present age). In the Iron Age men become evil, greedy and dishonest. Zeus/Jupiter tells the assembled gods on Mount Olympus that he must punish these men and proceeds to tell them how he dealt with an especially corrupt man, Lycaon, king of Arcadia, ...
Astronomical Ideas Fall 2012 Homework 4 Solutions 1. Two stars
... sequence; less massive stars burn slower, cooler, and redder). Measuring the most massive stars that still burn H on the main sequence is a clock, because we know that the cluster needs to be old enough so that all of the more massive stars have already burned up all of their Hydrogen and left the m ...
... sequence; less massive stars burn slower, cooler, and redder). Measuring the most massive stars that still burn H on the main sequence is a clock, because we know that the cluster needs to be old enough so that all of the more massive stars have already burned up all of their Hydrogen and left the m ...
Stellar Evolution
... and diameter. In fact, astronomers have discovered that the mass and the composition (makeup) of a star determine nearly all its other properties. ...
... and diameter. In fact, astronomers have discovered that the mass and the composition (makeup) of a star determine nearly all its other properties. ...
slides
... the white dwarf, but it will also cool off over time. So the lifetime of a PN is relatively short, just a few 10s of thousands of years. ...
... the white dwarf, but it will also cool off over time. So the lifetime of a PN is relatively short, just a few 10s of thousands of years. ...
21. The Milky Way Galaxy
... very small, about 10 mas/yr. It moves at a straight line across the sky. – The amount turns out to exactly reflect the motion of the Sun around the Galaxy => Sgr A* is clearly the Milky Way's dynamical heart. ...
... very small, about 10 mas/yr. It moves at a straight line across the sky. – The amount turns out to exactly reflect the motion of the Sun around the Galaxy => Sgr A* is clearly the Milky Way's dynamical heart. ...
Stellar Populations Science
... increasing the number of available galaxies by an order of magnitude, covering a wide range of morphological types, masses, and environments – Greater sensitivity and resolution allows high resolution spectroscopic analysis of TRGB stars out to ~4 Mpc, making it possible to study the detailed chemis ...
... increasing the number of available galaxies by an order of magnitude, covering a wide range of morphological types, masses, and environments – Greater sensitivity and resolution allows high resolution spectroscopic analysis of TRGB stars out to ~4 Mpc, making it possible to study the detailed chemis ...
Study Guide for 3RD Astronomy Exam
... Interpret the luminosity class of a star by naming the luminosity class and identifying if the star is in the “adult” phase or the “nursing home” phase of its evolution. Describe or identify how a parsec is defined. Convert stellar distances between parsecs and light years. Write or identify the def ...
... Interpret the luminosity class of a star by naming the luminosity class and identifying if the star is in the “adult” phase or the “nursing home” phase of its evolution. Describe or identify how a parsec is defined. Convert stellar distances between parsecs and light years. Write or identify the def ...
Summary: Stellar Distances
... Determining the Tangential Velocity The proper motion of a star, µ , is the annual rate at which its location (direction) on the celestial sphere changes. (This is in addition to the annual parallactic motion.) It is usually expressed in seconds-of-arc per year. Tangential velocities are obtained b ...
... Determining the Tangential Velocity The proper motion of a star, µ , is the annual rate at which its location (direction) on the celestial sphere changes. (This is in addition to the annual parallactic motion.) It is usually expressed in seconds-of-arc per year. Tangential velocities are obtained b ...
Stellar Evolution
... • Off the main sequence, there are – cool, bright stars in the upper right – hot, dim stars in the lower left ...
... • Off the main sequence, there are – cool, bright stars in the upper right – hot, dim stars in the lower left ...
Galaxies
... sometimes form into star clusters. When a star reaches the end of its evolution, it may return much of its gas back to the interstellar medium, which will be the source for a new generation of stars. Galaxies can be thought of as systems that turn gas into stars and back again. When we look at a gal ...
... sometimes form into star clusters. When a star reaches the end of its evolution, it may return much of its gas back to the interstellar medium, which will be the source for a new generation of stars. Galaxies can be thought of as systems that turn gas into stars and back again. When we look at a gal ...
Lecture 4: Molecular Clouds (1)
... Both HI and diffuse clouds can persist for long periods by means of pressure balance, because of the presence of a surrounding, more rarefied and warmer medium which prevents the internal (thermal) motion from dispersing the cloud. In giant molecular clouds, the main cohesive force is typically the ...
... Both HI and diffuse clouds can persist for long periods by means of pressure balance, because of the presence of a surrounding, more rarefied and warmer medium which prevents the internal (thermal) motion from dispersing the cloud. In giant molecular clouds, the main cohesive force is typically the ...
Stars and Galaxies
... • Mass of massive stars 6x that of sun • Take same path as medium-sized stars except for after red giant stage they do not become white dwarfs • Carbon atoms continue to fuse creating heavier elements like oxygen & nitrogen • Core of massive star so hot that fusion continues until the heavy element ...
... • Mass of massive stars 6x that of sun • Take same path as medium-sized stars except for after red giant stage they do not become white dwarfs • Carbon atoms continue to fuse creating heavier elements like oxygen & nitrogen • Core of massive star so hot that fusion continues until the heavy element ...
- ORIGINS Space Telescope
... To understand the sources and process of Reionization, it is essential to probe the population of low-metallicity, lowluminosity, and low stellar mass galaxies at z>6, which are expected to be dominant in terms of the number densities inferred from UV luminosity functions as well as their contributi ...
... To understand the sources and process of Reionization, it is essential to probe the population of low-metallicity, lowluminosity, and low stellar mass galaxies at z>6, which are expected to be dominant in terms of the number densities inferred from UV luminosity functions as well as their contributi ...
The Milky Way - 清華大學物理系歡迎頁 Welcome to
... Mmax ~ 100 solar masses a) More massive clouds fragment into smaller pieces during star formation. ...
... Mmax ~ 100 solar masses a) More massive clouds fragment into smaller pieces during star formation. ...
H II region
An H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived blue stars forged in these regions emit copious amounts of ultraviolet light that ionize the surrounding gas. H II regions—sometimes several hundred light-years across—are often associated with giant molecular clouds. The first known H II region was the Orion Nebula, which was discovered in 1610 by Nicolas-Claude Fabri de Peiresc.H II regions are named for the large amount of ionised atomic hydrogen they contain, referred to as H II, pronounced H-two by astronomers (an H I region being neutral atomic hydrogen, and H2 being molecular hydrogen). Such regions have extremely diverse shapes, because the distribution of the stars and gas inside them is irregular. They often appear clumpy and filamentary, sometimes showing bizarre shapes such as the Horsehead Nebula. H II regions may give birth to thousands of stars over a period of several million years. In the end, supernova explosions and strong stellar winds from the most massive stars in the resulting star cluster will disperse the gases of the H II region, leaving behind a cluster of birthed stars such as the Pleiades.H II regions can be seen to considerable distances in the universe, and the study of extragalactic H II regions is important in determining the distance and chemical composition of other galaxies. Spiral and irregular galaxies contain many H II regions, while elliptical galaxies are almost devoid of them. In the spiral galaxies, including the Milky Way, H II regions are concentrated in the spiral arms, while in the irregular galaxies they are distributed chaotically. Some galaxies contain huge H II regions, which may contain tens of thousands of stars. Examples include the 30 Doradus region in the Large Magellanic Cloud and NGC 604 in the Triangulum Galaxy.