– 1 – 1. Emission Lines in Nearby Galaxies 1.1.
... are almost always optically thin in HII regions and the density is low, so collisional de-excitation can be ignored. This results in an overpopulation of the metastable states and the forbidden transitions dominate the spectrum. If one can find a single ion with two or more detectable forbidden line ...
... are almost always optically thin in HII regions and the density is low, so collisional de-excitation can be ignored. This results in an overpopulation of the metastable states and the forbidden transitions dominate the spectrum. If one can find a single ion with two or more detectable forbidden line ...
GRAVITY: Observing the Universe in Motion
... far) unexplored strong field around SMBHs. The observed orbit of a hot spot on the last stable orbit will be dominated by strong gravitational effects like gravitational lensing and redshift (Figure 4). GRAVITY observations of the flaring BH will thus directly probe spacetime in the immediate vicin ...
... far) unexplored strong field around SMBHs. The observed orbit of a hot spot on the last stable orbit will be dominated by strong gravitational effects like gravitational lensing and redshift (Figure 4). GRAVITY observations of the flaring BH will thus directly probe spacetime in the immediate vicin ...
Thinking Outside the Sphere
... for the retrograde motion of the planets. In his scheme, each planet was attached to a small circle, called an epicycle, which moved it in a small orbit. The epicycle was attached in turn to a larger circle, or deferent, which moved around the earth. By adjusting the size and speed of these orbits, ...
... for the retrograde motion of the planets. In his scheme, each planet was attached to a small circle, called an epicycle, which moved it in a small orbit. The epicycle was attached in turn to a larger circle, or deferent, which moved around the earth. By adjusting the size and speed of these orbits, ...
Astronomy and Astrophysics (ASTRO) Iowa State University – 2013-2014 1
... An entirely web-based course covering topics in observing the sky and navigation by the stars for students with little or no previous experience. The course combines material on common naked-eye phenomena, such as daily and seasonal variations in the sky, with information on how these helped navigat ...
... An entirely web-based course covering topics in observing the sky and navigation by the stars for students with little or no previous experience. The course combines material on common naked-eye phenomena, such as daily and seasonal variations in the sky, with information on how these helped navigat ...
Hertzsprung–Russell diagram - Wikipedia, the free encyclopedia
... down along the line of the main sequence in the course of their lifetimes. Stars were thought therefore to radiate energy by converting gravitational energy into radiation through the Kelvin–Helmholtz mechanism. This mechanism resulted in an age for the Sun of only tens of millions of years, creatin ...
... down along the line of the main sequence in the course of their lifetimes. Stars were thought therefore to radiate energy by converting gravitational energy into radiation through the Kelvin–Helmholtz mechanism. This mechanism resulted in an age for the Sun of only tens of millions of years, creatin ...
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... nuclear-burning occurs partly under convective conditions. This process is generally known as hot bottom burning (HBB; Iben, 1973). Under these conditions, carbon, on the one hand, is converted into nitrogen, keeping the C/O ratio below 1, and on the other hand 7 Li is produced very efficiently by t ...
... nuclear-burning occurs partly under convective conditions. This process is generally known as hot bottom burning (HBB; Iben, 1973). Under these conditions, carbon, on the one hand, is converted into nitrogen, keeping the C/O ratio below 1, and on the other hand 7 Li is produced very efficiently by t ...
Molecular Gas in Galactic Environments Abstracts (Poster)
... I will present a new survey of 33 GHz radio continuum emission from local U/LIRGs carried out using the Karl G. Jansky Very Large Array (VLA). This is the first such survey and it combines high resolution, good sensitivity, and multi-configuration observations that have sensitivity to emission on al ...
... I will present a new survey of 33 GHz radio continuum emission from local U/LIRGs carried out using the Karl G. Jansky Very Large Array (VLA). This is the first such survey and it combines high resolution, good sensitivity, and multi-configuration observations that have sensitivity to emission on al ...
Astronomical Facts `n Stuff
... Absolute Brightness (Absolute Magnitude) A measure of the true brightness of an object. The absolute brightness or magnitude of an object is the apparent brightness or magnitude it would have if it were located exactly 32.6 light-years (10 parsecs) away. Absolute Magnitude A scale for measuring the ...
... Absolute Brightness (Absolute Magnitude) A measure of the true brightness of an object. The absolute brightness or magnitude of an object is the apparent brightness or magnitude it would have if it were located exactly 32.6 light-years (10 parsecs) away. Absolute Magnitude A scale for measuring the ...
Slide 1
... When a star dies, if the core has less mass than 1.4 times the sun, it will form a white dwarf. Gravity is trying to squeeze the core as small as it can get. It's stopped by the pressure of electrons trying to repel each other. This pressure counteracts gravity. Over billions of years, this hot core ...
... When a star dies, if the core has less mass than 1.4 times the sun, it will form a white dwarf. Gravity is trying to squeeze the core as small as it can get. It's stopped by the pressure of electrons trying to repel each other. This pressure counteracts gravity. Over billions of years, this hot core ...
Wolf-Rayet Stars
... tendency to refer to WN stars of classes 2 to 5 as early type (WNE) and classes 6 to 9 as late type (WNL). Similarly WC4-6 stars are designated as WCE, while WC7-9 stars are designated as WCL. Although there are important exceptions, WNE stars generally show no evidence for H emission while H emissi ...
... tendency to refer to WN stars of classes 2 to 5 as early type (WNE) and classes 6 to 9 as late type (WNL). Similarly WC4-6 stars are designated as WCE, while WC7-9 stars are designated as WCL. Although there are important exceptions, WNE stars generally show no evidence for H emission while H emissi ...
A Spectroscopic Survey of a Sample of Active M Dwarfs.
... to see whether their X-ray brightness indicated strong chromospheric activity: what fraction of Fleming’s stars are dMe stars? Fleming (1998) had shown that these stars probably have small proper motions, so we were interested in seeing whether other indications of youth are present. It has long bee ...
... to see whether their X-ray brightness indicated strong chromospheric activity: what fraction of Fleming’s stars are dMe stars? Fleming (1998) had shown that these stars probably have small proper motions, so we were interested in seeing whether other indications of youth are present. It has long bee ...
Science with the Constellation
... Since their discovery, quasars and active galactic nuclei (AGN) have stood out as uniquely luminous objects in the Universe. Today we are confident that their ultimate power source is the release of gravitational energy sustained by an accretion disk, which is feeding matter directly into a central ...
... Since their discovery, quasars and active galactic nuclei (AGN) have stood out as uniquely luminous objects in the Universe. Today we are confident that their ultimate power source is the release of gravitational energy sustained by an accretion disk, which is feeding matter directly into a central ...
CFBDSIR J1458+ 1013B: A Very Cold (> T10) Brown Dwarf in a
... serve as laboratories for understanding gas-giant extrasolar planets as well as the faint end of the star formation process. The coolest known brown dwarfs, the T dwarfs, have temperatures (≈600– 1400 K), bolometric luminosities (≈ 10−4 to 10−6 L⊙ ), molecule-dominated (H2 O and CH4 ) IR spectra, an ...
... serve as laboratories for understanding gas-giant extrasolar planets as well as the faint end of the star formation process. The coolest known brown dwarfs, the T dwarfs, have temperatures (≈600– 1400 K), bolometric luminosities (≈ 10−4 to 10−6 L⊙ ), molecule-dominated (H2 O and CH4 ) IR spectra, an ...
Stellar radii from long-baseline interferometry
... The cool dwarfs 61 Cyg A and B are the nearest stars in the northern hemisphere. They are a visual binary pair with a very long orbital period (≈ 700 yrs). In 1838, 61 Cyg became the first star whose distance from Earth was estimated accurately (Bessel 1838), shortly before Procyon’s, and it is now k ...
... The cool dwarfs 61 Cyg A and B are the nearest stars in the northern hemisphere. They are a visual binary pair with a very long orbital period (≈ 700 yrs). In 1838, 61 Cyg became the first star whose distance from Earth was estimated accurately (Bessel 1838), shortly before Procyon’s, and it is now k ...
Chapter 1 Telescopes 1.1 Lenses
... the diameter of the objective of a telescope, the greater the number of stars that can be seen. Planets and other astronomical objects in the solar system are magnified using a telescope (unlike stars which are point objects and are seen through telescopes as point images no matter how large the mag ...
... the diameter of the objective of a telescope, the greater the number of stars that can be seen. Planets and other astronomical objects in the solar system are magnified using a telescope (unlike stars which are point objects and are seen through telescopes as point images no matter how large the mag ...
Kinetic equilibrium of iron in the atmospheres of cool stars
... present approach to the analysis of the reference stars is based on a number of assumptions. Atmospheric models are calculated for all stars (including the Sun) according to the same type of input parameters, boundary conditions, and constraint equations. We thus intentionally avoid the use of empir ...
... present approach to the analysis of the reference stars is based on a number of assumptions. Atmospheric models are calculated for all stars (including the Sun) according to the same type of input parameters, boundary conditions, and constraint equations. We thus intentionally avoid the use of empir ...
WORD - Astrophysics
... observations have driven our knowledge of the processes leading to star formation, of how the interplay between gravity and nuclear reactions determine stellar evolution, and ultimately, the physical principles that explain the existence of some of the most exotic states of matter in the Universe: n ...
... observations have driven our knowledge of the processes leading to star formation, of how the interplay between gravity and nuclear reactions determine stellar evolution, and ultimately, the physical principles that explain the existence of some of the most exotic states of matter in the Universe: n ...
NAS biographical memoir of Martin Schwarzschild
... Nature and nurture conspired to provide an ideal scientific environment for Martin Schwarzschild, but the early years must have been difficult. He was born to a distinguished and assimilated German-Jewish family in 1912—two years before the outbreak of World War I—when his father, Karl Schwarzschild ...
... Nature and nurture conspired to provide an ideal scientific environment for Martin Schwarzschild, but the early years must have been difficult. He was born to a distinguished and assimilated German-Jewish family in 1912—two years before the outbreak of World War I—when his father, Karl Schwarzschild ...
previous lectures - Gwynedd Astronomy Society
... Spin offs from space research Solar observing Science fiction Extra-solar planetary systems One man and his Dob – observing from the summit of ...
... Spin offs from space research Solar observing Science fiction Extra-solar planetary systems One man and his Dob – observing from the summit of ...