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Absorption Line

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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 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.
acceleration: A change in a velocity; a change in either speed or direction. (See velocity.) ...

absorption line: a more or less narrow range of wavelengths in a spectrum that is darker than neighboring wavelengths. Absorption lines are seen in stars.

absorption line
A dark line in a spectrum that represents the absorption of energy at a particular wavelength of light. Each element on the periodic table absorbs energy at unique wavelengths.

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.
The process of growth of an object due to the gradual accumulation of material.

~ - A dark line superimposed on a continuous spectrum when a gas absorbs light from a continuous source that is hotter than the absorbing gas
Acceleration - The rate of change of velocity. An acceleration may involve a change of speed, direction of motion, or both ...

~ spectrum
Dark lines superimposed on a continuous spectrum.
The rate at which an object's velocity changes due to a change in speed, a change in direction, or both.

~: 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.

~. 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.

When sunlight is split by a prism, at first glance it appears to produce a continuous spectrum. However, closer scrutiny with a spectroscope shows that the solar spectrum is interrupted by a large number of narrow dark lines, as shown in Figure 4.4.

~s 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.

Dark lines in a spectrum, produced when light or other electromagnetic radiation coming from a distant source passes through a gas cloud or similar object closer to the observer.

An ~ is produced when a photon of just the right energy is absorbed by an atom, kicking an electron to a higher energy orbit. The photon had energy = the difference in energy of the energy orbits.

~s of PI
The equivalent width of PI 9796(2) in the sun is 0.012. According to Underhill (1977) it is present in an A 2Ia star.
~s of PII
The PII line 4127(16) is presentin B 5Ia stars and ultraviolet lines are also visible in B 7 and B 9V stars (Artru et al. 1989).

A dark line in a continuous spectrum caused by absorption of light.

~s against a continuous spectrum are seen as the photons emitted at particular wavelengths are emitted in all directions, so would produce a dark line.
(b) The largest transition would give a photon of the shortest wavelength. This would be from n = 6 to n = 2.
(c) This is at 410 nm ...

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 ...

~s: Dark lines superimposed over a bright continuous spectrum background, created when a cooler gas absorbs photons from a hotter source.

Narrow spectral features that represent a reduction in intensity over a small wavelength range. They are caused by the loss of photons that raise an atom from a particular energy state to a higher energy state.
absorption spectrum ...

~s 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.

The ~ 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.

The ~s of a solar or other stellar spectrum.
frequency - (n.) ...

Dark ~s 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. The image below shows a segment of the solar spectrum, in which many such lines can be seen.

Broad ~s are direct evidence of outflow from AGNs, at very respectable velocities. The primary questions are then (1) what is this absorbing region and (2) is the BAL phenomenon an intrinsic property of a few QSOs or do most QSOs look like this if viewed from certain directions?

Emission and ~s in radio astronomy usually originate from atoms and small molecules or molecular ions in gaseous form, and molecular transitions at radio wavelengths are usually rotational.

Search for ~s from the evaporated atmosphere of extrasolar planets in the visible.
abstract ...

Relatively few ~s. Lines of ionized helium and other lines of highly ionized atoms. Hydrogen lines appear only weakly. Peak of light in UV part of spectrum.
B ...

~ (NASA SP-7, 1965) A minute range of wavelength (or frequency) in the electromagnetic spectrum within which radiant energy is absorbed by the medium through which it is passing.

~ The absence or reduction of radiation at one or several adjacent wavelengths in a continuous spectrum. absorption spectrum Continuous spectrum interrupted by ~s or a continuous spectrum having a number of discrete wavelengths missing or reduced in intensity.

H-alpha. This ~ 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.

telluric lines ~s in a solar spectrum produced by constituents of the atmosphere of the earth itself rather than by gases in the outer solar atmosphere such as those responsible for the Fraunhofer lines.

p=39938#comment-434673 Ganzy (5) said:

Can someone correct me please if I'm wrong, but if I were to analyze the entire spectrum of light that is being given off by this cargo ship burning up on re-entry, would I expect to see black ~s in specific parts of the spectrum that ...

The reason temperatures affect ~s is not too difficult to understand in a general way. ~s are produced when an electron of an atom is moved from one orbital shell to another one of higher energy through the absorption of a photon.

Asymmetric ~ profiles are the result of the superposition of multiple ~s, each corresponding to the same atomic transition (for example the "K" line of calcium), but occurring in interstellar clouds with different radial velocities.

The precise position (wavelength) at which known emission and ~s are detected can be used to measure the redshift of the observed object. For example, if the spectral line of Hβ (486.2 nm) is detected at 487.

A second candidate was identified by methane ~s in Gliese 229B, a faint object orbiting the M1 star Gliese 229 in the constellation Lepus, 18.6 light years away. It appears to have a mass of , and to be 44 AU away from Gliese 229 (Glanz 1995, Oppenheimer et al. 1995).

Most prominent would be the star itself, and whatever emission and ~s come from the star's surface. But what about the gas?

This detection helps explain the physical shape of previously poorly-understood related ice ~s.
Orton et al. 1982 A spectrum of the disk of Jupiter was obtained from the Kuiper Airborne Observatory, covering the 100 to 300 cm^-1 spectral range.

Within this spectra, astronomers can study emission and ~s 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.

These locations are called ~s and are caused by a particular element in the star's atmosphere.

Note the characteristic ~ features including strong lines for Hα, Hβ, Hγ and Hδ - the Balmer Series. The overall shape of the spectrum approximates a black body curve with a peak wavelength. This can be used to determine the effective temperature of the star.

A dark-line spectrum (also called a absorption spectrum) consists of dark ~s superimposed on a bright continuous spectrum. An absorption spectrum is created when light from an incandescent source passes through a cooler gas that absorbs photons.

Gamma Velorum also has the nickname the Spectral Gem of the Southern Skies because it emits bright lines instead of dark ~s, which results in an exotic looking spectrum. Gamma Velorum is actually a multiple star system, composed of at least six stars.

B stars have spectra that are characterized by ~s of neutral helium which reach their maximum intensity at B2, and strong Balmer lines of hydrogen and lines of singly ionized oxygen and other gases.

Balmer lines (J. Balmer)
Emission or ~ in the spectrum of hydrogen that arise from transitions between the second (or first excited) state and higher energy states of the hydrogen atom.

He assigned letters to the black ~s 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 - ...

Johannes Franz Hartmann (1865-1936) was a German astrophysicist who, in 1904, discovered clouds of interstellar calcium gas (he detected the ~s of ionized calcium atoms using spectrography while studying binary stars).

- Apodis (Eta Apodis) is classified as an Am star or metallic-line star, an A-type star that is chemically peculiar and whose spectrum has strong ~s of some metals and deficiencies of others.

The infrared spectrum of 2003 UB313, compared to that of Pluto, shows the marked similarities between the two bodies. Arrows denote methane ~s.

* As x-rays leave a neutron star, they have to pass through the star's magnetic field. This field absorbs certain wavelengths, creating specific ~s in the spectrum. These are the cyclotron resonance ~s that allow the direct measurement of the magnetic field strength.

A hot variable star with peculiar emission and ~s in its spectrum.
A mechanism for extracting rotational energy from a black hole.

Spectrometers are instruments that spread light out into wavelengths called "spectra," which look something like rainbow-colored bars. Using the spectra, scientists can look for and study the "emission lines" and "~s" that are sort of fingerprints of atoms and molecules that may be ...

This is a detailed spectrum of the star Arcturus - a red giant. It was taken from an American Observatory and shows a continuous spectrum displayed over 50 strips. Within each strip the vertical black bars are ~s which give information about the chemical composition of the star.

The CBR had, however, been detected and its temperature deduced in 1941, seven years before Gamow's prediction. Based on the study of narrow ~ features in the spectra of stars, ...

electromagnetic radiation arranged in order of wavelength. A rainbow is a natural spectrum of visible light from the Sun. Spectra are often punctuated with emission or ~s, which can be examined to reveal the composition and motion of the radiating source.

Damped Lyman Alpha Absorbers (also: Damped Lyman alpha systems or Damped Lyman alpha absorption systems) are gaseous objects detected in the spectra of quasars, with a column density larger than 1020 atoms/cm2. Their spectra consist of neutral hydrogen Lyman alpha ~s, ...

(Image: European Southern Observatory) Astronomers then used the VLT's 8.2-m Kueyen telescope to obtain a spectrum of the objects. This superimposed the light of the two stars, but the combined result shows the deep ~s expected from a red dwarf.

(The higher the gravity, the more the compression of the gas, and the closer the atoms are to each other, which affects the way in which they produce their ~s.) The gravity in turn depends on mass and radius. Gravity measure with the above radius gives a mass of 1.

Spectra are often punctuated with emission or ~s, which can be examined to reveal the composition and motion of the radiating source.
Sunspot A temporary disturbed area in the solar photosphere that appears dark because it is cooler than the surrounding areas.

See also: See also: What is the meaning of Absorption lines, Spectrum, Spectra, Astro, Solar?

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