Strömgren photometric system

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Strömgren photometric system (uvby) (sometimes also referred as Strömgren - Crawford photometric system) is four-colour medium-band photometric system (plus H-beta filter) for stellar classification. It was pioneered by the Danish astronomer Bengt Strömgren in 1956 and extended by his colleague the American astronomer David L. Crawford in 1958.

Contents 1 Indices and parameters 2 Mean wavelength and half-widths of response functions 3 References 4 External links 5 See also

[edit] Indices and parameters

V, b-y, m1, c1, beta

m1 = (v - b) - (b - y)

c1 = (u - v) - (v - b)

y magnitudes are well-correlated with Johnson-Morgan V magnitudes.

[edit] Mean wavelength and half-widths of response functions

	u	v	b	y	beta narrow	beta wide
Peak wavelength (nm)	350	411	467	547	485.8	485
Half-width (nm)	30	19	18	23	2.9	12.9

[edit] References

1. Strömgren, Bengt, 1956, Two-dimensional spectral classification of F stars through photoelectric photometry with interference filters, Vistas in Astronomy, Vol. 2, Issue 1, pp. 1336–1346
2. Crawford, David L., 1958, Two-Dimensional Spectral Classification by Narrow-Band Photometry for B Stats in Clusters and Associations, Astrophysical Journal, Vol. 128 (September 1958), pp. 185–206

[edit] External links

1. The Asiago Database on Photometric Systems
2. The uvby photometric system

[edit] See also

Stellar classification