The Beer photometric system
Beer A. 1964, MNRAS 128, 261
Analysis has been completed of 3360 photoelectric measurements of the Hgamma
intensity in 461 stars of spectral types O and B, situated in the northern sky;
93 per cent of these are brighter than 7.5 mag. Three consistent series of
measurements were obtained in the years 1960-1963, using the spectrometer at
the f/18 coude focus of the 36-in reflector of the Cambridge Observatories.
154 of the stars were used as standards, adopting Petrie's
system of absolute magnitudes. The photometric measuring-errors
corresponded to absolute-magnitude errors of about +-0.2 for stars of a mean
luminosity of -2.5 mag. There is, addition, the possibility of some physical
intrinsic scatter in the relation between absolute magnitude and Hgamma
strength, and that of errors in the assignment of standard absolute magnitudes.
Some discussion has been made of emission-line stars,
and particularly of the relation of these measurements to other absolute
magnitude classification, of the use of eclipsing binaires in this work, and
of the problem of calibration of the distance scale. Using
interstellar absorption, estimated from colour excesses, new distances have
been obtained for more than three hundred OB-stars. These have been mapped
on the plane of the Milky Way, in order to make a comparison with the
distribution of HI-region as revealed by 21-cm radio measurements, in
continuation of the earlier work of 1961 concerned with southern B-stars.
A star catalogue is given in Section 7.
Access to the data and references
Asiago Database on Photometric System (ADPS)
Indices and Parameters
Rgamma = [(a) star / (a) lamp] / [(b) star / (b) lamp]
where (a) stands for the comparison region and (b) for Hgamma.
- (a) Comparison regions
- 4255 - 4289 Å
- 4394 - 4427 Å
- (b) Hgamma region
- 4325 - 4357 Å
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Last update: 13 September 2002