Spectrum of white dwarf stars in NGC 6397

This chart displays the spectra of four White Dwarf stars in globular cluster NGC 6397, obtained with ANTU/FORS1 and identified as such from these data. The spectra were shifted vertically so that they do not overlap. The wavelength is indicated along the abscissa; the intensity along the ordinate. A "standard" spectrum of a White Dwarf star (of spectral type DA - the hydrogen-rich variety) is shown at the top for comparison. Broad absorption lines from hydrogen atoms in the atmosphere are visible. Although the signal-to-noise ratio is quite small, especially for the lower spectra of the fainter stars, they all show the same strong, broad absorption lines as the comparison spectrum. This permits to classify them unambiguously as WD stars. Individual differences, for instance of the widths of the absorption lines, are clearly present and point to different surface gravity and masses.

Oikeudet:

ESO

Kuvasta

Tunnistus:eso9953b
Tyyppi:Taulukko
Julkaisupäivä:16. joulukuuta 1999
Vastaavat julkaisut:eso9953
Koko:764 x 962 px

Kohteesta

Nimi:NGC 6397
Tyyppi:Milky Way : Star : Evolutionary Stage : White Dwarf
Milky Way : Star : Grouping : Cluster : Globular
Etäisyys:7000 valovuotta
Kategoria:Star Clusters
Stars

Kuvaformaatit

Suuri JPEG
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Kokoruudun JPEG
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Värit ja suotimet

KaistaTeleskooppi
Optinen
B
Very Large Telescope
FORS1