Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994mnras.268..771b&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Vol. 268, NO. 3/JUN1, P. 771, 1994
Astronomy and Astrophysics
Astronomy
82
Techniques: Photometric - Stars: Fundamental Parameters
Scientific paper
In order to find the transformation equations between calculated and observed photometric systems, sensitivity functions for the passbands of the UBV and Washington systems are combined with observations of stellar fluxes to derive stellar colours. Comparison of these colours with photometry of the same stars gives transformation equations, which are then used to convert a grid of synthetic colours, computed from synthetic spectra for Population I stars, from the synthetic colour systems to the observational systems in a completely model-independent way. We then measure synthetic colours from models for 35 stars with well-known atmospheric parameters and apply the previously determined transformations, yielding calibrated synthetic colours. These are compared with the observed colours for these objects. This comparison indicates that the synthetic (B - V) colours are excellent throughout (within 0.02-0.03 mag of the observations). On the other hand, synthetic (U - B) colours, particularly for the cooler stars, tend to be systematically too blue. The (U - B) errors are typically 0.1 mag for stars with (B - V) < 1, and can reach nearly 0.4 mag for models of cooler stars. In some cases this disagreement is believed to be caused by too high temperatures being adopted for the coolest stars, but deficiencies in the atomic and molecular line data are likely to contribute as well. To investigate the role played by line list variations, synthetic spectra have been computed using different line lists. Detailed graphical comparisons of synthetic and observed spectra for the Sun are presented to show the fit given by the different line lists. With the exception of one list which predicts many unobserved lines, the differences in synthetic colours which result from the use of these other lists are generally small. The effect of a `sea' of background weak lines is also explored. We suggest that the missing U-band opacity in the models may arise from a continuous rather than line absorption process.
Bell Roger A.
Paltoglou Georgios
Tripicco Michael J.
No associations
LandOfFree
The Calibration of Synthetic Colours does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Calibration of Synthetic Colours, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Calibration of Synthetic Colours will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1505433