How is it possible to identify elements in stars?

Answer 1

Analysis of their light through spectroscopy is all but a few of the known chemical elements have been identified in stars. A spectroscope or spectrograph spreads out incoming light into its component wavelengths, and is usually recorded with a Charged Couple Device Camera which sends it to a computer. Long gone are the days when astronomers studied spectra visually or recorded them on photographic plates or film. It is then displayed as a graph or a CCD image with a reference spectrum so the astronomer can have a point of reference to make a meaningful analysis. Some 70 elements have been detected in the Sun and other stars out of the known elements of the periodic table. The ones that have not are mostly only synthesized in nuclear reactors and particle accelerators on Earth and do not exist in nature except in the the remnants of a recent supernova. Light emitted from stars or other celestial objects contains a wealth of information about that object. Each element absorb or emit discrete wavelengths of light in a pattern of wavelengths that is as unique as a fingerprint. As atoms gain or lose electrons, that too leaves it's mark in a star's spectrum. A spectrogram consists of a pattern or lines on a light or dark background, and each feature on a spectrum is called a spectral line or band depending on it's width. Much of what we know about the stars started with laboratory analysis of elements with spectroscopes and theoretical models which made predictions of how elements would behave in the conditions that prevail within stars. Spectra contain a wealth of information about stars. The elements that are detected have a great deal to say about the star's age and condition, but spectra are useful in other ways. They also reveal a star's temperature, rotation rate, velocity, luminosity, the strength and structure of the magnetic field, and even the presence of planets.

Answer 2

When excited, individual elements emit light at specific wavelengths, called the spectrum for that element. By looking at a spectrum from a star and the relative intensities of specific lines (wavelengths) you can estimate the composition.

You can also calculate how fast the star is moving relative to us by the extent to which the lines shift (red shift -to longer wavelengths-means moving away, blue shift-to shorter wavelengths-means moving toward you).

Answer 3

It's called spectroscopy. By separating light into its component spectra, you see which wavelengths (colors) are present or absent in the light. (They do this by passing it through narrow slits).

You're probably familiar with spectra from letting sunlight pass through glass prisms. Imagine the resulting "rainbow" but with certain parts of it missing. Imagine a tall, narrow rectangle, with red at one end and rainbow bands crossing it down to violet at the other end. Then draw little black lines across it with a pencil. The black lines are the absorption lines - and their layout is unique to each element like a thumb print.

By recognizing these signatures, the presence of elements is determined. This is actually how helium was discovered. No one had ever encountered helium but its spectra was noticed while observing the sun. That's how helium got its name.

Answer 4

Hello -

By examining the dark lines in the spectrum that we see when collecting light from the star, we can identify the characteristic pattern by comparing it to patterns that we see when we heat specific elements in the lab.

Answer 5

spectral analysis

Answer 6

the colors! they tell u how hot it is and other stuff
=)