The Smith photometric system

Basic Reference

L.F. Smith


Results of five-colour narrow band photoelectric observations are given for forty-three Wolf-Rayet (WR) stars in the Magellanic Clouds and for seventy-seven WR stars in the Galaxy. Photometric classification criteria are established and most WR stars in the Magellanic Clouds are classified. Absolute magnitude are found to be correlated with spectral subclass; among the WN stars, those in the lowest excitation subclasses are the most luminous.

It is found tha the WR stars in the Large Magellanic Cloud are very similar to stars of the same spectral subclass in the Galxy. However, subclass WC6, WC7, WC8 and WC9 are completely absent from the Magellanic Clouds, and WN6 stars are rare.

The relationship between absolute magnitude and spectral appearance of the WC5 + OB stars and the WN4 + OB stars is consistent with the hypothesis that these are binary systems in which WR stars, similar to single stars of the same type, are associated with O or B stars.


Access to the data and references

Asiago Database on Photometric System (ADPS)

Indices and Parameters

v, b-v, u-b, b-v1, u1-b


u1 : Schott
Central wavelength : 3500 Å ; Width : 80 Å
u : Schott
Central wavelength : 3650 Å ; Width : 100 Å
b : Spectrolab
Central wavelength : 4270 Å ; Width : 70 Å
v : Spectrolab
Central wavelength : 5160 Å ; Width : 130 Å
v1 : Schott
Central wavelength : 5500 Å ; Width : 230 Å


RCA 1P21
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Last update: 21 May 1996