absorption spectrum
A spectrum of absorption lines or bands, produced when light from a hot source, itself producing a continuous spectrum, passes through a cooler gas.
Absorption Line
An absorption line will appear in a spectrum if an absorbing material is placed between a source and the observer. This material could be the outer layers of a star, a cloud of interstellar gas or a cloud of dust.
Absorption spectrum: Most stars are surrounded by outer layers of gas that are less dense than the core. The photons emitted from the core cover all frequencies (and energies).
absorption line: A dark line in a spectrum; produced by the absence of photons absorbed by atoms or molecules.
absorption spectrum (dark-line spectrum): A spectrum that contains absorption lines.
Absorption and Radiation Activities and Demonstration Video -- Spacesuits are constructed of materials with desirable thermal properties that reduce dependence on the heating and cooling system.
ABSORPTION SPECTRA
Astronomers first became aware of the true extent of dark interstellar clouds in the 1930s as they studied the optical spectra of distant stars.
Absorption line. A break of depression in a continuous spectrum caused by the absorption of photons within narrow wavelengths by some types of atom, ion, or molecule.
ABSORPTION - Transfer of energy to a medium as a particle or electromagnetic radiation passes through it. Absorption of electromagnetic radiation is the combined result of Compton scattering, σ, and photoelectric absorption, τ.
Absorption line: A dark line or band at a particular wavelength on a spectrum, formed when a substance between a radiating source and an observer absorbs electromagnetic radiation of that wavelength.
absorption line Dark line in an otherwise continuous bright spectrum, where light within one narrow frequency range has been removed.
acceleration The rate of change of velocity of a moving object.
absorption line
A narrow dark line within a spectrum. It is caused by specific gases absorbing a portion of radiation, and its width represents the relative abundance of the gases.
Absorption Line - A dark line superimposed on a continuous spectrum when a gas absorbs light from a continuous source that is hotter than the absorbing gas ...
absorption lines
dark lines in a spectrum caused by the absorption of light by atoms or molecules in a star or planet's atmosphere
accretion disk ...
Absorption spectroscopy refers to a range of techniques employing the interaction of electromagnetic radiation with matter.
Absorption lines Dark lines interrupting a continuous color spectrum, caused by a cool gas between the light source and the observer. Cool gas absorbs light in the same frequencies as it emits when hot, e.g. double yellow line of sodium.
Absorption
(a) A process in which a gas is taken up by a liquid or solid, or in which a liquid is taken up by a solid. In absorption, the substance absorbed goes into the bulk of the material.
Absorption only
Suppose we have a light source, embedded in a uniform cloud of absorbers (think of a light in a thick fog, where the water droplets act as the absorbers). In this case, we set j to zero.
Absorption-line systems again require that the QSO be beyond all the absorbing material unless all the intervening material has noncosmological redshifts as well.
[edit] Absorption
Main article: Absorption spectroscopy
Absorption spectroscopy is a technique in which the power of a beam of light measured before and after interaction with a sample is compared.
Balmer-Absorption Dominated (BAD) Nuclei. Presumably post-starburst nuclei seen sufficiently long after the starburst event that the original OB stars have evolved, but recently enough that the A supoergiants are still in evidence.
Absorption spectroscopy uses the range of the electromagnetic spectra in which a substance absorbs.
Absorption of their light by intervening objects
Quasars are ideal objects to use to learn about the distant - and for us practically invisible - Universe.
ABSORPTION SPECTRUM
An absorption spectrum (also called a dark-line spectrum) consists of dark absorption lines superimposed on a bright continuous spectrum.
Absorption lines
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies.
Contents ...
Absorption Lines: Dark lines superimposed over a bright continuous spectrum background, created when a cooler gas absorbs photons from a hotter source.
Absorption and reflection features which allow the identification of atmospheric composition are electronic transitions (UV), molecular vibrations (IR and near IR), and molecular rotation (IR, far IR).
absorption spectrum - Dark lines superimposed on a continuous spectrum.
achromatic - Free of chromatic aberration.
almanac - A book or table listing astronomical events.
ABSORPTION LINES
Absorption Lines are dark lines superimposed over a bright continuous absorption spectrum. Each dark line is formed as a cooler gas absorbs photons emitted by a particular element from a hotter source.
Absorption lines from hydrogen in quasar spectra tells us that there is a lot of material between us and the quasars.
Gravitational Lensing ...
re-absorption of radiation from accelerated electrons by other nearby electrons; this is a possible source of low frequency turnovers observed in the radio spectra of compact sources.
synchotron emission - (n.) ...
The absorption line of neutral calcium at 4227 Angstroms is thus strong in cool M-type dwarf stars, in which the pressure is high and the temperature is low.
Dark absorption lines in the sun's spectrum and that of other stars are called Fraunhofer lines after Joseph von Fraunhofer (1787-1826) who observed them in 1817.
1. An absorption feature of calcium usually has a wavelength of 3934 Å, but it is observed in a galaxy to have a wavelength of 4002 Å. How fast is this galaxy moving, and is it moving towards or away from you?
The X-ray absorption efficiency is extremely dependent on what kind of phosphor you have and how thick it is. At 6 keV, P43 exceeds 85absorption efficiency.
Home
Imagine Science ...
"At noon the absorption is weak but in the evening it is much stronger," says Jessica Sunshine, Deptuy Project Investigator for the Deep Impact mission which also observed signatures of water and hydroxyl on the Moon.
line absorption See absorption spectrum. linear 1. Of or pertaining to a line. 2.
Apart then from absorption there will be a discontinuous change in brightness in the apparent disk at that value of the angular radius d which corresponds to tangential emission from the upper lever r' of this mirage-forming region.
fluorescence The absorption of a photon of one energy, or wavelength, and re-emission of one or more photons at lower energies, or longer wavelengths. [More Info: Field Guide] ...
Stellar spectra
Absorption lines from photosphere
Hydrogen Balmer series changes in strength :
weak at low temp : all in ground state (n=1)
weak at high temp : all ionized
strongest at about 10,000K (A0 stars) ...
H-alpha. This absorption line of neutral hydrogen falls in the red part of the visible spectrum and is convenient for solar observations. The H-alpha line is universally used for observations of solar flares.
decimal coefficient of absorption (NASA SP-7, 1965) See absorption coefficient. decimal digit (NASA SP-7, 1965) 1. One of the digits used in decimal notation, i.e., 1,2,3,4,5,6,7,8,9, or 0.
2. One of 10 possible conditions.
examine scattering, absorption, and solar heating within the atmospheres of Saturn/Titan
search for lightning, aurorae, and airglow
investigate the gravitational interactions among Saturn's rings and satellites ...
1930 - Robert Trumpler uses open cluster observations to quantify the absorption of light by interstellar dust in the galactic plane; this absorption had plagued earlier models of the Milky Way, ...
Spectral Line A line in a spectrum due to the emission or absorption of electromagnetic radiation at a discrete wavelength. Spectral lines result from discrete changes in the energy of an atom or molecule.
Huge absorptions by carbon molecules (carbon monoxide, cyanogen or CN, carbon-2, and carbon-3) are present, giving the star a remarkable spectrum, a combination of them cutting out blue and violet light and making the star quite red.
The discrete emission of light by cometary atoms, radicals, or ions is due to the selective absorption of sunlight followed by its reemission either at the same wavelength (resonance) or at a different wavelength (fluorescence).
Molecular absorption, mainly due to atmospheric ozone and water, is a minor one, about 0.02 magnitudes per air mass. More importantly, Rayleigh scattering by air molecules accounts for up to 0.14 magnitude increases per air mass.
That brings on a polar cap absorption event (PCA), with high D region absorption along radio signal paths passing over the polar areas of the Earth.
What is a coronal mass ejection?
The HST Faint Object Spectrograph (FOS) detected many gaseous absorptions associated with the impact sites and followed their evolution over the next month.
Stars can be classified by their surface temperature and their absorption spectra. There are seven main types of stars.
At around one billion years in age, red dwarf stars and L-type brown dwarfs are red, while the less massive T dwarf is dimly magenta, due to the absorption of green wavelengths by sodium and potassium atoms.
The spectrum from a star could have absorption or emission lines. It is because when atoms are in low pressure, they can only emit or absorb light of certain wavelengths.
Within this spectra, astronomers can study emission and absorption lines which are the fingerprints of atoms and molecules. An emission line occurs when an electron drops down to a lower orbit around the nucleus of an atom and loses energy.
Ionospheric absorption makes AKR observable from space only. These "parallel voltages" accelerate electrons to auroral energies and seem to be a major source of aurora.
He assigned letters to the black absorption lines in the Solar Spectrum. These resonance lines arise from energy absorption by elements in the outer atmospheres of stars that are cooler than the stellar gases below. Back to Top
- G - ...
Gamma Velorum also has the nickname the Spectral Gem of the Southern Skies because it emits bright lines instead of dark absorption lines, which results in an exotic looking spectrum.
S-type Moderately bright (albedo=0.10-0.22), spectra with moderate to strong absorption bands, greenish to reddish in color. M-type Moderately bright (albedo=0.10-0.18), spectra with few absorption bands, reddish in color.
Spectra of Beta Pictoris show absorption features which are currently believed to be due to cometary like clouds of gas occultating the star from the debris left over from planetary formation.
The gas is virtually transparent to visible light; there is weak optical absorption by certain trace atoms (sodium, calcium) and molecules (cyanogen, carbon hydride).
A spectrum in which there are no absorption or emission lines.
coronograph
A telescope that blocks light from the disk of a star so that fainter surrounding objects and structures can be observed.
 See also: Light, Energy, Solar, Sun, Spectrum
|
