Spectral Classification Through Photo-Electric Narrow-Band Photometry

Strömgren, Bengt

doi:10.1146/annurev.aa.04.090166.002245

Cited by 241 publications

(151 citation statements)

References 0 publications

Supporting

Mentioning

148

Contrasting

Order By: Relevance

“…To accomplish this, filter systems are tailored to select regions in stellar spectra where the variations of the atmospheric parameters leave their characteristic traces with enough prominence to be detected in photometric data. Beginning with the influential papers by Johnson (1966) and Strömgren (1966), which describe the basis of broad-and et al 2012), intermediate-and narrow-band photometry is more limited in this respect, although still very informative (e.g., Mould & Bessell 1982;Bonnell & Bell 1982;Yong et al 2008;Árnadóttir et al 2010;Casagrande et al 2014a).…”

Section: Introductionmentioning

confidence: 99%

Synthetic stellar photometry – I. General considerations and new transformations for broad-band systems

Casagrande¹,

VandenBerg²

2014

Monthly Notices of the Royal Astronomical Society

263

321

View full text Add to dashboard Cite

After a pedagogical introduction to the main concepts of synthetic photometry, colours and bolometric corrections in the Johnson-Cousins, 2MASS, and HST-ACS/WFC3 photometric systems are generated from MARCS synthetic fluxes for various [Fe/H] and [α/Fe] combinations, and virtually any value of E(B − V) 0.7. The successes and failures of model fluxes in reproducing the observed magnitudes are highlighted. Overall, extant synthetic fluxes predict quite realistic broad-band colours and bolometric corrections, especially at optical and longer wavelengths: further improvements of the predictions for the blue and ultraviolet spectral regions await the use of hydrodynamic models where the microturbulent velocity is not treated as a free parameter. We show how the morphology of the colour-magnitude diagram (CMD) changes for different values of [Fe/H] and [α/Fe]; in particular,how suitable colour combinations can easily discriminate between red giant branch and lower main sequence populations with different [α/Fe], due to the concomitant loops and swings in the CMD. We also provide computer programs to produce tables of synthetic bolometric corrections as well as routines to interpolate in them. These colour-T eff -metallicity relations may be used to convert isochrones for different chemical compositions to various bandpasses assuming observed reddening values, thus bypassing the standard assumption of a constant colour excess for stars of different spectral type. We also show how such an assumption can lead to significant systematic errors. The MARCS transformations presented in this study promise to provide important constraints on our understanding of the multiple stellar populations found in globular clusters (e.g., the colours of lower main sequence stars are predicted to depend strongly on [α/Fe]) and of those located towards/in the Galactic bulge.

show abstract

Section: Introductionmentioning

confidence: 99%

Synthetic stellar photometry – I. General considerations and new transformations for broad-band systems

Casagrande¹,

VandenBerg²

2014

Monthly Notices of the Royal Astronomical Society

263

321

View full text Add to dashboard Cite

show abstract

“…The original calibration, however, gives excellent absolute magnitudes (as compared to the cluster parallax) for the Hyades cluster (Strömgren 1963) and was therefore adopted. The results are tabulated in Table I, where AM v is de- Furthermore, galactic space velocities U,V,W were calculated from the photometric absolute magnitudes.…”

Section: The M 1 Indexmentioning

confidence: 99%

“…Strömgren (1963). Dots refer to M v calculated from uvby photometry, while the arrowheads refer to the group parallax.…”

Section: The M 1 Indexmentioning

confidence: 99%

Abundance Homogeneity and Absolute Magnitudes of the Hyades Moving Group

Breger¹

1968

PASP

View full text Add to dashboard Cite

The Hyades moving group shows a distribution of mi metal-abundance indices intermediate between the Hyades-cluster and field-star distributions, indicating a mixture of both. Group parallaxes give a mean absolute magnitude brighter by 0"3 than is obtained from the Strömgren Ci index, while for the Hyades cluster the agreement is very good. Several possible reasons for this are discussed. It is recommended that membership in moving groups should not be used to obtain absolute magnitudes for any individual star.

show abstract

“…A&A 514, A59 (2010) Here we provide precise uvbyβ photometric distances for most of the stars with complete photometry included in Kaltcheva's (2003) catalog and use them to outline the overall structure and characteristics of the Carina spiral feature. A detailed description of the photometric quantities used in this photometric system can be found in Strömgren (1966). Among the wide variety of photometric systems available today the uvbyβ photometry is arguably better suited for the study of individual stars in terms of stellar luminosity than any other photometric system in wide use and proven to provide reliable stellar distances (cf.…”

Section: Introductionmentioning

confidence: 99%

The Carina spiral feature: Strömgren-β photometry approach

Kaltcheva¹,

Scorcio²

2010

A&A

View full text Add to dashboard Cite

Aims. In recent years a significant development has become evident in the study of the stellar structure of the Galactic disk. This is especially true for the 3rd Galactic quadrant, where the stellar population was extensively investigated beyond 10 kpc, revealing details about the warped geometry of the thin and thick disks and outer arm. The 4th Galactic quadrant offers even better opportunity to follow the distribution of the young stellar populace to a large distance, since the line of sight is parallel to the largest single segment of a spiral arm seen from our position in the Galaxy: the Carina spiral feature. This paper further contributes to the study of the structure of the Galactic disk in the direction of Carina field utilizing homogeneous photometric distances of a sample of about 600 bright early-type stars seen in this direction up to 6 kpc. Methods. The derived stellar distances are based on uvbyβ photometry. All O and B type stars with uvbyβ data presently available are included in the study. Results. The photometry-derived parameters allow us to study the structure and characteristics of this segment of the Carina arm. We find that the stellar distribution is consistent with a location of the apparent edge of the arm at l = 287 • . Toward the edge of the arm the warp of the Galactic plane can be traced up to 6 kpc where it reaches negative 200 pc. The field toward the edge seems to be much more complex than harboring just one OB association, and it is likely that some of the apparent concentrations in this field represent parts of long segments of the edge. In the 284 • -289 • longitude range an interarm space about 1 kpc wide is found beyond 850 pc from the Sun. The giant molecular clouds and open clusters do not follow the edge of the arm as defined by the OB stars and indicate a possible presence of an age gradient in a direction perpendicular to the formal Galactic plane.

show abstract

Spectral Classification Through Photo-Electric Narrow-Band Photometry

Cited by 241 publications

References 0 publications

Synthetic stellar photometry – I. General considerations and new transformations for broad-band systems

Synthetic stellar photometry – I. General considerations and new transformations for broad-band systems

Abundance Homogeneity and Absolute Magnitudes of the Hyades Moving Group

The Carina spiral feature: Strömgren-β photometry approach

Contact Info

Product

Resources

About