ﻻ يوجد ملخص باللغة العربية
Based on a large sample of disk and halo giant stars, for which accurate effective temperatures derived through the InfraRed Flux Method (IRFM) exist, a calibration of the temperature scale in the Vilnius, Geneva, RI(C) and DDO photometric systems is performed. We provide calibration formulae for the metallicity dependent T_eff vs color relations as well as grids of intrinsic colors and compare them with other calibrations. Photometry, atmospheric parameters and reddening corrections for the stars of the sample have been updated with respect to the original sources in order to reduce the dispersion of the fits. Application of our results to Arcturus leads to an effective temperature in excellent agreement with the value derived from its angular diameter and integrated flux. The effects of gravity on these T_eff vs color relations are also explored by taking into account our previous results for dwarf stars.
We have used an updated version of the empirically and semi-empirically calibrated BaSeL library of synthetic stellar spectra of Lejeune et al. (1997, 1998) and Westera et al. (1999) to calculate synthetic photometry in the UBVRIJHKLLM, HST-WFPC2, Ge
This paper report results from the first long-term BV(RI)c photometric CCD observations of three variable pre-main-sequence stars collected during the period from February 2007 to January 2020. The investigated stars are located in the field of the P
The Gemini Planet Imager (GPI) is a new facility instrument for the Gemini Observatory designed to provide direct detection and characterization of planets and debris disks around stars in the solar neighborhood. In addition to its extreme adaptive o
The SIRTF InfraRed Spectrograph (IRS) is faced with many of the same calibration challenges that were experienced in the ISO SWS calibration program, owing to similar wavelength coverage and overlapping spectral resolutions of the two instruments. Al
Parallaxes for 581 bright K giants have been determined using the Hipparcos satellite. We combine the trigonometric parallaxes with ground based photometric data to determine the K giant absolute magnitudes. For all these giants, absolute magnitude e