Stellar physical parameters from Str ömgren photometry. Application to the young stars in the Galactic anticenter survey

Abstract

Aims. The aim is to derive accurate stellar distances and extinctions for young stars of our survey in the Galactic anticenter direction using the Strömgren photometric system. This will allow a detailed mapping of the stellar density and absorption toward the Perseus arm. Methods. We developed a new method for deriving physical parameters from Strömgren photometry and also implemented and tested it. This is a model-based method that uses the most recent available stellar atmospheric models and evolutionary tracks to interpolate in a 3D grid of the unreddened indexes [m1], [c1] and Hbeta. Distances derived from both this method and the classical pre-Hipparcos calibrations were tested against Hipparcos parallaxes and found to be accurate. Results. Systematic trends in stellar photometric distances derived from empirical calibrations were detected and quantified. Furthermore, a shift in the atmospheric grids in the range Teff=[7000,9000]K was detected and a correction is proposed. The two methods were used to compute distances and reddening for about 12000 OBA-type stars in our Strömgren anticenter survey. Data from the IPHAS and 2MASS catalogs were used to complement the detection of emission line stars and to break the degeneracy between early and late photometric regions. We note that photometric distances can differ by more than 20%, those derived from the empirical calibrations being smaller than those derived with the new method, which agree better with the Hipparcos data.

13 pages, 15 figures

References in corpus (6)

• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• Spiral structure in the outer Galactic disk. I. The Third Galactic Quadrant
• Initial Data Release from the INT Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS)
• On the galaxy spiral arms' nature as revealed by rotation frequencies
• Mapping the interface between the Local and Loop I bubbles using Stromgren photometry

Cited by in corpus (2)

• The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
• First detection of the field star overdensity in the Perseus arm