Issue |
Astron. Astrophys. Suppl. Ser.
Volume 123, Number 1, May II 1997
|
|
---|---|---|
Page(s) | 83 - 92 | |
DOI | https://doi.org/10.1051/aas:1997307 | |
Published online | 15 May 1997 |
An analysis of the currently available calibrations in Strömgren photometry by using open clusters
Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Avda. Diagonal 647, E-08028 Barcelona, Spain
Send offprint request to: C. Jordi
Received:
5
August
1996
Accepted:
9
September
1996
In recent years, several authors have revised the calibrations used
to compute physical parameters
(,
, log g, [Fe/H])
from intrinsic colours in the
photometric system.
For reddened stars, these intrinsic colours can be computed through the
standard relations among colour indices for each of the regions
defined by Strömgren (1966) on the HR diagram.
We present a discussion of the coherence of these calibrations
for main-sequence stars. Stars from open clusters are used
to carry out this analysis. Assuming that individual reddening
values and distances
should be similar for all the members of a given open cluster,
systematic differences among the calibrations used in each of the
photometric regions might arise when comparing mean reddening values
and distances for the members of each region.
To classify the stars into Strömgren's regions we extended
the algorithm presented by Figueras et al. (1991) to a wider range of spectral
types and luminosity classes.
The observational ZAMS are compared with the
theoretical ZAMS from stellar evolutionary models, in the
range
K. The discrepancies are also discussed.
Key words: stars: fundamental parameters / open clusters and associations: general / stars: distances / HR diagram / stars: general / techniques: photometric
© European Southern Observatory (ESO), 1997