Calibration of Synthetic Photometry for B and early-A Stars

Details Calibration of Synthetic Photometry for B and early-A Stars Calibration of Synthetic Photometry for B and early-A Stars

Jun 2002

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002aas...200.9302f&link_type=abstract

American Astronomical Society, 200th AAS Meeting, #93.02; Bulletin of the American Astronomical Society, Vol. 34, p.954

Astronomy and Astrophysics

Astrophysics

1

Scientific paper

We have developed a procedure for modeling the observed energy distributions of early-type stars (Teff ~ 10000 - 30000 K) over a wavelength range spanning the UV through the near-IR. The analysis relies on line-blanketed model atmospheres, as computed with R.L. Kurucz's ATLAS9 program, and a parametrized representation of the wavelength-dependent effects of interstellar extinction. With this technique, study of a stellar energy distribution --- even if severely reddened --- can reveal the basic properties of the star (Teff, log g, and [m/H]), as well as E(B-V), the shape of the interstellar extinction curve, and R = AV/E(B-V). The primary dataset to be exploited using this method is the Final Archive of the International Ultraviolet Explorer (IUE) satellite, which contains UV spectrophotometric observations (1200 - 3200Å) for hundreds of early-type stars over a wide range of reddenings, including eclipsing binary systems, open cluster members, and field stars. Unfortunately the wavelength range of these UV data does not include critical diagnostic information needed for determining, in particular, stellar surface gravity and extinction curve normalization. These diagnostics are located in the visible and near-IR portions of the spectrum and thus, to realize the full potential of our analysis, we need to supplement the IUE data with optical and near-IR measurements. The most widespread body of such data are Johnson UBVRIJHKL and Stromgren uvby + Hβ photometry. The problem is how to calibrate synthetic Johnson and Stromgren photometry of stellar model fluxes so that it can be compared with real stellar observations. In this poster we illustrate our procedure for calibrating synthetic Johnson and Stromgren photometry for early-type stars. We utilize a calibration sample of ~50 well-observed, lightly reddened A and B stars whose physical properties can be constrained by a combination of Hipparcos distances and stellar interior models. We discuss the results of the calibration process and demonstrate the energy distribution fitting procedure for a number of reddened and unreddened stars. Future applications of the analysis are noted. This work is supported by Astrophysics Data Program grant NAG5-7113 to Villanova University.

Affiliated with

Also associated with

No associations

Rating

Calibration of Synthetic Photometry for B and early-A Stars 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 Calibration of Synthetic Photometry for B and early-A Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Calibration of Synthetic Photometry for B and early-A Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1893254