The Maitzen photometric system

Basic Reference

Maitzen H.M. 1976, Astron. Astrophys. 51, 223

Abstract

For a statistical investigation of the broad-band flux depression in the visible spectra of Ap and related stars, a five filter photometric system was used conatining Strögren vby and two intermediate band filters g1 at lambda 5020 Å and g2 at lambda 5240 Å. Three indices were observed for 93 Ap, 23 Am 8 Hg-Mn and 57 normal A stars (9 of this sample are members of the Ap rich open cluster NGC 2516). (b-y) as temperature indicator, m1 as lambda 4100 Å depression parameter and a1 = g2 - (g1 + y) / 2 which is proposed as new photometric index for the flux depression at lambda 5200 Å. It is shown that a can be neasured with higher accuracy than the other parameters and that it is possible to assign Ap character to stars with excess values in a (compared to a-values of normal A stars). Contrary to m1 the a-values of Am and Hg-Mn stars are essentially normal. Virtually all Ap stars with (b-y) < 0.1 have peculiar a-values.

Content

Access to the data and references

Asiago Database on Photometric System (ADPS)

Indices and Parameters

a, Da, Da0

Filters

g1 and g2 are Schott (IL) interference filters

The parameters are defined by :

where a0 = a0(b-y) for normal stars.

Photomultiplier

EMI 6256, EMI 9502
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Jean-Claude.Mermilliod@obs.unige.ch
Last update: 2 April 1998
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