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Strömgren photometric system

The Strömgren photometric system, abbreviated also as uvbyβ or simply uvby, and sometimes referred as Strömgren - Crawford photometric system, is a four-colour medium-passband photometric system plus Hβ (H-beta) filters for determining magnitudes and obtaining spectral classification of stars. Its use was pioneered by the Danish astronomer Bengt Strömgren in 1956{{cite journal

It is often considered to be a powerful tool and successful investigating the brightness and effective temperature of stars. This photometric system also has a general advantage as it can be used to measure the effects of reddening and interstellar extinction.{{cite journal

Wavelength and half-width response functions

The following table shows the characteristics of each of the filters used (represented colors are only approximate): :{| class="wikitable"

+Strömgren photometric system filter wavelength and half-width response functions
!
!u
!v
!b
!y
!βnarrow
!βwide
-
!Peak wavelength (nm)
350
-
! align="center"
} Note: colors are only approximate and based on wavelength to sRGB representation (when possible).

Indices

There are four main highly applied and technical indices: (b-y); m_1; c_1; and \beta.

  • m_1 = (v-b) - (b-y)
  • c_1=(u-v) - (v-b)
  • \beta = \beta_{narrow} - \beta_{wide}

Where;

  • y magnitudes are well-correlated with Johnson-Morgan V magnitudes (its V band).
  • (b-y) is sensitive to stellar temperature (measure of Paschen continuum).
  • c_1 is sensitive to the surface gravity (measures Balmer discontinuity strength).
  • m_1 is sensitive to the metallicity (measure of line blanketing).

References

References

  1. "Light wavelength to RGB Converter".
Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

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