Chapter 21 - apel slice
... eyes are too small to gather much light. Telescopes are instruments that collect and focus light and other forms of electromagnetic radiation. Telescopes make distant objects appear larger and brighter. A telescope that uses lenses or mirrors to collect and focus visible light is called an optical t ...
... eyes are too small to gather much light. Telescopes are instruments that collect and focus light and other forms of electromagnetic radiation. Telescopes make distant objects appear larger and brighter. A telescope that uses lenses or mirrors to collect and focus visible light is called an optical t ...
File - Science Website
... Describe, in as much detail as you can, what forces allow a stable star to exist and how the star may eventually form a black hole. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. ...
... Describe, in as much detail as you can, what forces allow a stable star to exist and how the star may eventually form a black hole. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. ...
The Mighty Hunter in the Winter Sky By Shannon Jackson
... Five constellations are always in our northern sky. Other groupings appear seasonally, and then disappear as they fall below the horizon. There are five constellations, however, which seem to circle Polaris (po LAR us), also known as the North Star. The North Star always stays put while the other st ...
... Five constellations are always in our northern sky. Other groupings appear seasonally, and then disappear as they fall below the horizon. There are five constellations, however, which seem to circle Polaris (po LAR us), also known as the North Star. The North Star always stays put while the other st ...
Self-similarity in the chemical evolution of galaxies and the delay
... lifetimes etc. All of these are described in detail in Y13. The only parameter that we treat as a variable in the present contribution is the delay time distribution (DTD) of SNeIa. The DTD describes the probability for a SN Ia to explode as a function of the time elapsed since a star formation even ...
... lifetimes etc. All of these are described in detail in Y13. The only parameter that we treat as a variable in the present contribution is the delay time distribution (DTD) of SNeIa. The DTD describes the probability for a SN Ia to explode as a function of the time elapsed since a star formation even ...
the magellanic clouds newsletter - Keele University Astrophysics
... NGC 1818. We apply both an isochrone-fitting approach and χ2 minimization using Monte Carlo simulations, for different mass-ratio cut-offs, q, and present a detailed comparison of the methods’ performance. Both methods yield the same radial binary fraction profile for the same cluster, which therefo ...
... NGC 1818. We apply both an isochrone-fitting approach and χ2 minimization using Monte Carlo simulations, for different mass-ratio cut-offs, q, and present a detailed comparison of the methods’ performance. Both methods yield the same radial binary fraction profile for the same cluster, which therefo ...
IND 6 - 1 Stars and Stellar Evolution In order to better understand
... inside a star! IRON is used as a proxy for all “metals” (because it’s abundant) and metallicity is measured as the logarithm of the amount of iron relative to the amount of hydrogen. One interesting thing we can determine from metallicity is a rough age. The more “metalrich” the star is, the more ...
... inside a star! IRON is used as a proxy for all “metals” (because it’s abundant) and metallicity is measured as the logarithm of the amount of iron relative to the amount of hydrogen. One interesting thing we can determine from metallicity is a rough age. The more “metalrich” the star is, the more ...
Chapter 17 Star Stuff
... • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses ...
... • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses ...
The role of black holes in galaxy formation and evolution
... A. C. Fabian11, C. S. Frenk12, A. Khalatyan13, H. Netzer14, A. Mahdavi15, J. Silk4, M. Steinmetz1 & L. Wisotzki1 Virtually all massive galaxies, including our own, host central black holes ranging in mass from millions to billions of solar masses. The growth of these black holes releases vast amount ...
... A. C. Fabian11, C. S. Frenk12, A. Khalatyan13, H. Netzer14, A. Mahdavi15, J. Silk4, M. Steinmetz1 & L. Wisotzki1 Virtually all massive galaxies, including our own, host central black holes ranging in mass from millions to billions of solar masses. The growth of these black holes releases vast amount ...
Chapter 17 Star Stuff How does a star`s mass affect nuclear fusion
... Stellar Mass and Fusion • The mass of a main sequence star determines its core pressure and temperature • Stars of higher mass have higher core temperature and more rapid fusion, making those stars both more luminous and shorter-lived • Stars of lower mass have cooler cores and slower fusion rates, ...
... Stellar Mass and Fusion • The mass of a main sequence star determines its core pressure and temperature • Stars of higher mass have higher core temperature and more rapid fusion, making those stars both more luminous and shorter-lived • Stars of lower mass have cooler cores and slower fusion rates, ...
Project 8 : Stellar Spectra: Classification
... Absorption lines occur when an electron absorbs energy from the spectrum to move up the energy levels in the atom. Since hydrogen has only one electron, this electron is usually in the ground state. But as the temperature rises, the average electron gains m ...
... Absorption lines occur when an electron absorbs energy from the spectrum to move up the energy levels in the atom. Since hydrogen has only one electron, this electron is usually in the ground state. But as the temperature rises, the average electron gains m ...
Our Galaxy
... not known yet. 3. Most young stars are found in: ) The center, b) in Halo, outskirts of our galaxy, c) disk of our galaxy d) this is not known yet because MWG is too dusty for us to determine this info. 1. a, 2. c, 3. c ...
... not known yet. 3. Most young stars are found in: ) The center, b) in Halo, outskirts of our galaxy, c) disk of our galaxy d) this is not known yet because MWG is too dusty for us to determine this info. 1. a, 2. c, 3. c ...
Galaxies, stars and planets
... and contains materials with a range of properties that far exceeds anything that can be replicated in laboratories on the Earth. Temperatures range from close to absolute zero (−273.15 ºC) in dense clouds of gas and dust from which stars form, up to many millions of degrees in the interiors of stars ...
... and contains materials with a range of properties that far exceeds anything that can be replicated in laboratories on the Earth. Temperatures range from close to absolute zero (−273.15 ºC) in dense clouds of gas and dust from which stars form, up to many millions of degrees in the interiors of stars ...
Magnetic susceptibility, magnetization, magnetic moment and
... some cases, intensity ratios are very sensitive to both T e and ne . In this case, two or more diagnostics must be used at the same time to ...
... some cases, intensity ratios are very sensitive to both T e and ne . In this case, two or more diagnostics must be used at the same time to ...
The star-forming environment of an ultraluminous X-ray
... a small group of OB stars, but is not associated with any massive young clusters nor with any extraordinary massive stars. The brightest point source in the Chandra error circle is consistent with a single blue supergiant (BSG) of mass ≈20 M and age ≈10 Myr. A few other stars are resolved inside th ...
... a small group of OB stars, but is not associated with any massive young clusters nor with any extraordinary massive stars. The brightest point source in the Chandra error circle is consistent with a single blue supergiant (BSG) of mass ≈20 M and age ≈10 Myr. A few other stars are resolved inside th ...
Spectroscopic confirmation of a galaxy at redshift z=8.6
... Although we cannot derive the characteristics of the stellar population in UDFy-38135539, similarly selected galaxies at lower redshifts, z < 5–7, seem to be young (ages between 10 and 100 million years, Myr) and have both low metallicity and low extinction15–17. Plausible characteristics for the st ...
... Although we cannot derive the characteristics of the stellar population in UDFy-38135539, similarly selected galaxies at lower redshifts, z < 5–7, seem to be young (ages between 10 and 100 million years, Myr) and have both low metallicity and low extinction15–17. Plausible characteristics for the st ...
Disk Instability Models
... Heretical Explanation for Microlensing Planets • Most stars form in regions of high-mass star formation (e.g., Orion, Carina) where their protoplanetary disks can be photoevaporated away by nearby O stars. • Photoevaporation converts gas giant protoplanets into ice giants if the protoplanet orbit ...
... Heretical Explanation for Microlensing Planets • Most stars form in regions of high-mass star formation (e.g., Orion, Carina) where their protoplanetary disks can be photoevaporated away by nearby O stars. • Photoevaporation converts gas giant protoplanets into ice giants if the protoplanet orbit ...
Preface 1 PDF
... can be inferred. Thanks to helioseismology, we know that the Sun rotates as a solid body in the radiative interior and that the convective envelope rotates differentially, with a shear layer in between. Such a shear is thought to be one of the ways in which the large-scale magnetic field of the Sun c ...
... can be inferred. Thanks to helioseismology, we know that the Sun rotates as a solid body in the radiative interior and that the convective envelope rotates differentially, with a shear layer in between. Such a shear is thought to be one of the ways in which the large-scale magnetic field of the Sun c ...
Post-Main Sequence Evolution – Low and Intermediate Mass Stars
... AGB stars are known to lose mass at a prodigious rate during their final stages, around 10-5 - 10-4 solar masses per year. This obviously cannot persist for much over 100,000 years. The mass loss is driven in part by the pulsational instability of the thin helium shell. These pulses grow more violen ...
... AGB stars are known to lose mass at a prodigious rate during their final stages, around 10-5 - 10-4 solar masses per year. This obviously cannot persist for much over 100,000 years. The mass loss is driven in part by the pulsational instability of the thin helium shell. These pulses grow more violen ...
Comparison of low- and high-mass star formation
... constantly replenished by the global collapse. The most massive object is located near the minimum of the global potential well and accretes the global collapse-fed material at a rate higher than any other object. Nevertheless, its accretion rate is only ∼10% of the total rate. In other words, the v ...
... constantly replenished by the global collapse. The most massive object is located near the minimum of the global potential well and accretes the global collapse-fed material at a rate higher than any other object. Nevertheless, its accretion rate is only ∼10% of the total rate. In other words, the v ...
From ATLASGAL to SEDIGISM: Towards a Complete 3D View of the
... data (Csengeri et al., 2016a). This comparison allowed us to estimate the dense gas fraction in the Galactic Plane; we find an average value of ~ 2 % for the Galaxy. Using simple but realistic assumptions, we could also convert the total flux density measured in the maps to a total mass of molecular ...
... data (Csengeri et al., 2016a). This comparison allowed us to estimate the dense gas fraction in the Galactic Plane; we find an average value of ~ 2 % for the Galaxy. Using simple but realistic assumptions, we could also convert the total flux density measured in the maps to a total mass of molecular ...
Astrophysics - Part 2
... Balmer absorption lines The hydrogen absorption lines found in the visible spectrum of the hottest stars (O, B and A only) are called Balmer lines. In such stars hydrogen atoms exist with electrons in the n = 2 state. When these atoms are excited by the absorption of photons from the photosphere th ...
... Balmer absorption lines The hydrogen absorption lines found in the visible spectrum of the hottest stars (O, B and A only) are called Balmer lines. In such stars hydrogen atoms exist with electrons in the n = 2 state. When these atoms are excited by the absorption of photons from the photosphere th ...
Lecture notes
... smaller volume, and thus the entire flux must get out of a smaller area. However heavy stars also have higher effective temperatures. which leads to that the outer convection zone disappears. An important consequence of convection is that the material in the convection zone is mixed and the composit ...
... smaller volume, and thus the entire flux must get out of a smaller area. However heavy stars also have higher effective temperatures. which leads to that the outer convection zone disappears. An important consequence of convection is that the material in the convection zone is mixed and the composit ...
Chapter 20
... Its path across the H-R diagram is essentially a straight line—it stays at just about the same luminosity as it cools off. Eventually the star dies in a violent explosion called a supernova. ...
... Its path across the H-R diagram is essentially a straight line—it stays at just about the same luminosity as it cools off. Eventually the star dies in a violent explosion called a supernova. ...
Chapter 8 Pre-galactic enrichment of the IGM 8.1 Summary
... negative feedback would be compensated by an extended epoch of Pop III star formation. At present, we do not know when Pop III star formation ceases. We view our choice of Mmin = 5 × 105 M! at z = 15 as a hedge between competing effects. ...
... negative feedback would be compensated by an extended epoch of Pop III star formation. At present, we do not know when Pop III star formation ceases. We view our choice of Mmin = 5 × 105 M! at z = 15 as a hedge between competing effects. ...
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.