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Emission Line

Astronomy  Emission  Emission Nebula

Emission Line
An emission line will appear in a spectrum if the source emits specific wavelengths of radiation. This emission occurs when an atom, element or molecule in an excited state returns to a configuration of lower energy.

Emission lines are used in physics, chemistry, and astronomy to determine what kind of gas is doing the emission. Every element has a different electronic structure, and will thus have a different emission line fingerprint.

Emission lines in accreting binaries
Accreting binary systems (Cataclysmic Variables and X-ray Binaries) are among the strongest sources of X-rays on the sky.

The spectra we encountered in Chapter 3 are examples of continuous spectra.

emission line: a more or less narrow range of wavelengths in a spectrum that is brighter than neighboring wavelengths. Emission lines are seen in quasars.

Emission Line Variability of the Accreting Young Brown Dwarf 2MASSW J1207334-393254: From Hours to Years
preprint ...

Emission lines and the far-UV spectrum. Since recombination lines (and a few others) are powered ultimately by parts of the spectrum we can't see directly, they may give our only information on what happens between the UV and soft X-ray ranges.

Emission Line: A bright line in a spectrum caused by the emission of photons from atoms.
Emission Nebula: A cloud of gas that is excited by the ultraviolet radiation from hot stars.

emission line spectrum
A spectrum that contains bright emission lines.
emission nebula
A glowing gaseous nebula whose spectrum has bright emission lines.

Emission Line
A bright line in a spectrum caused by the emission of photons from atoms.
Emission Nebula ...

Emission lines. Specific wavelengths of light that are brighter than adjoining wavelengths seen in spectra.
Ephemeris. A table or list of the predicted position of an object such as a planet.

Emission Line - A narrow, bright region of the spectrum. Emission lines are produced when electrons in atoms jump from one energy level to lower energy level
Energy Flux - The rate at which a wave carries energy through a given area ...

emission line
Within a spectrum, an excess amount of energy that is emitted at a specific wavelength. Emission lines in a spectrum usually appear as slender slivers of light on a dark background.

Emission Lines
Bright lines produced in a spectrum by a luminous source, such as a star or a bright nebula. Compare absorption lines.
Emission Measure (EM) ...

The Emission Line Corona
Click on image for larger version.
Early observations of the visible spectrum of the corona revealed bright emission lines at wavelengths that did not correspond to any known materials.

Narrow Emission Line Galaxy
A toxic silvery element belonging to the lanthanoid series of metals. It occurs in association with other lanthanoids.

Emission lines
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.

emission line Bright line in a specific location of the spectrum of radiating material, corresponding to emission of light at a certain frequency.

emission line - A discrete bright spectral line.
ephemeris - A table that gives the position of a celestial body at various times, or other astronomical data.

Emission lines are produced by hot gas. If the hot gas is moving at a pretty good rate of speed, then the Doppler effect comes into play - the emission lines could be shifted to different wavelengths.

Emission Lines: The bright lines seen against a darker background, created when a hot gas emits photons characteristic of the elements of which the gas is composed.

emission line
In spectroscopy, a particular wavelength of emitted radiation, more intense than the background continuum.
emission measure ...

emission line - (n.)
A wavelength at which radiation is emitted, creating a bright line in the spectrum.
emission nebula - (n.) ...

Emission lines with peculiarity
Emission lines with ^P-Cygni//gr 304.446667, 38.032944^ profile
ev ...

The emission line for Fe XI, occurs at 789.2 nanometres (nm), and the first images of the corona at this wavelength reveal some surprises, ...

21-cm emission line
The important radio radiation at 21-cm wavelength from interstellar neutral atomic hydrogen.
aberration of starlight ...

e: Emission lines are present (usually hydrogen)
m: Abnormally strong "metals" (elements other than hydrogen and helium) for a star of a given spectral type; usually applied to A stars ...

Spectral emission lines suggest an expanding shell of gas surrounding the star.
Other Designations For This Star
Hipparcos Identifier (HIP Number) ...

What produces an emission line spectrum? Do you need a thermal source in the background?
Can you see emission lines if a thermal source is in the background? What does their visibility depend on?

emission line A minute range of wavelength (or frequency) in the electromagnetic spectrum within which radiant energy is being emitted by a radiating substance. See spectral line, emission spectrum.

emission line emission nebula emission spectrum Spectrum containing bright lines or a set of discrete wavelengths produced in a rarefied incandescent gas.

A spectrum in which there are no absorption or emission lines.
The faint outer atmosphere of the Sun that is exposed during a total solar eclipse.
Coronae ...

continuum The continuous spectrum that any object would produce if no absorption or emission lines were present. Any body above absolute zero emits a spectrum, the shape of which is dependant on its temperature.

Wolf-Rayet stars (NASA Thesaurus) Very luminous, very hot (as high as 50,000K) stars whose spectra have broad emission lines (mainly He I and He II, which are presumed to originate from material ejected from the stars at very high velocities.

If the gas is rarefied, then the photon emitted from an individual atom will be able to escape from the gas without being altered and you will see the appropriate emission lines (Law 2).

1943 - Carl Keenan Seyfert identifies six spiral galaxies with unusually broad emission lines, named Seyfert galaxies,
1949 - J.G. Bolton, G.J. Stanley, and O.B. Slee identify NGC 4486 (M87) and NGC 5128 as extragalactic radio sources, ...

The way we can measure the extent of the shift, however, is through the absorption and emission lines.

The Orbiting Solar Observatory OSO-3 made the first certain detection of celestial gamma rays in 1972, and OSO-7 detected gamma-ray emission lines in the solar spectrum.

I think the inverted color picture above is centered on the H-alpha emission line, so we are seeing the abundant hydrogen, mostly in the sun's photosphere. But then, on the left hand side of the disk you can notice some fuzzy floating thing.

These filters only pass the two Oxygen III emission lines, the Hydrogen Beta emission line, and the wavelengths between these two, making them most useful for observing emission or planetary nebulae.

Optical photographs subsequently taken of their spectra showed locations for emission lines at wavelengths that were at odds with all celestial sources then familiar to astronomers.

SPIN-FLIP TRANSITION - Origin of the 21-cm emission line that originates with a neutral 1H atom. The proton and the electron each have a quantum “spin,' which points either “up' or “down.

Emission lines result from warm gas overlying a cold background so that the intensity (or flux or radiation temperature) at the line frequency is sharply higher compared to nearby wavelengths.

The spectral type gives an indication of the surface temperature of the star, along with size and any special properties such as emission lines, variability or an unspecificed peculiarity.

Central star temperatures are commonly calculated by using the intensity of nebular emission lines to estimate the amount of ultraviolet radiation from the star and then comparing that to the amount of visual radiation derived from the visual ...

In addition, however, sunlight also contains many bright emission lines, characteristic of hydrogen, calcium and other elements.

A research team of astronomers, has successfully detected a carbon emission line in the most distant radio galaxy known so far in the early universe.

The spectral type of stars is a system of classification of stars based on the stars' spectra, emission lines that correlate with each star's surface temperature (and color). There are seven major spectral types.

A class of spiral and barred spiral galaxies with small but very bight nuclei whose spectra show emission lines. The Seyfert galaxies are subdivided into two types depending on their emission lines.

CMY has an advatage of covering forbidden oxygen and hydrogen beta emission lines around 500nm (major components of the light from emission and planetary nebulas) which are frequently excluded by RGB filters.

Astronomers using ISO discovered emission lines from interstellar water vapor in a variety of sources including star forming regions, planetary nebulae and near formed stars.

BZ Crucis is a Be star classified as a B1IVe class star, a B class subgiant showing emission lines in its spectrum. It is a Gamma Cassiopeiae type variable star, which is to say a shell star that has a circumstellar gas disk around the equator.

It was the first planetary nebula to be observed with a spectroscope; the observers were surprised to find emission lines in the spectrum of this object.

Schmidt puzzled over the photographic spectrum for months before he recognized that the strong, broad emission lines in the star were the familiar hydrogen-Balmer series, but redshifted by 15%.

Its nucleus (center) has bright emission lines, including visible wavelengths. The brightness varies over relatively short time periods (less than a year). They may have massive black holes at their centers.

where νobs is the observed frequency of an emission line, and νemit is the emitted frequency of the emission line.

Definition: Seyfert galaxy: A spiral galaxy whose nucleus shows bright emission lines; one of a class of galaxies first described by C. Seyfert.
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Hydrogen Alpha - A specific emission line of ionized hydrogen at 656.3 nanometers. Hydrogen-alpha emissions are responsible for the red color in emission nebulae.

Their spectrum has broad and very intense emission lines, probably indicative of violent surface activity.

In physics, the Lyman series is the series of transitions and resulting emission lines of the hydrogen atom as an electron goes from n = 2 to n = 1 ....
-alpha hydrogen radiation at a wavelength
Wavelength ...

6.08 Gas surrounding a star may absorb energy, causing...
absorption lines.
an explosion.
emission lines.

Seyfert galaxy
A spiral galaxy whose nucleus shows bright emission lines; one of a class of galaxies first described by C. Seyfert.

It is an emission nebula created by a fast stellar wind of a Wolf-Rayet star, an evolved, massive star showing strong emission lines of helium and nitrogen or helium, carbon and oxygen. It is approximately 5,000 light-years distant.

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 "absorption lines" that are sort ...

Other stars have spots, as well. Called starspots, these patches can't be seen directly, but are inferred by measurements of the effects of magnetic fields and rotation upon the narrow emission lines of atoms on the star's surface.

An interstellar cloud of gas and dust in which hot embedded stars ionize much of the cloud's gas atoms causing the nebula to emit its own light. The name is derived from the pattern of emission lines in the spectra of these nebulas.

Shell Star
A type of star which is believed to be surrounded by a thin envelope of gas, which is often indicated by bright emission lines in its spectrum.

These very hot stars show broad emission lines and strong stellar winds (about 500 to 800 km/sec, sometimes even significantly higher). How the gas of the atmosphere is accelerated to reach such an high velocity is not yet known.

Often, the redshift of an object can be measured by examining atomic absorption or emission lines in its spectrum. Redshifts can be caused by the motion of a source away from an observer.

The VLT spectrum was the first to reveal the far red range where carbon emission lines are predicted; the absence of the lines puts constraints on the role of atmospheric chemistry when life started on earth.

However, the deeper, hot corona of Star Aa is much more variable than that of Star Ab. The extreme ultraviolet spectra of Stars Aa and Ab display the presence of iron emission lines from Fe XV to Fe XXIV (more).

See also: See also: Emission, Astro, Spectrum, Star, Solar

Astronomy  Emission  Emission Nebula

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