Luminosity Distance and Extinction by Submicrometer-sized Grains

The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains a...

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Bibliographic Details
Main Authors: R. Siebenmorgen, Frank Heymann, R. Chini
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
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Online Access:https://doi.org/10.3847/2041-8213/ada894
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Summary:The distance to the stars is a fundamental parameter, which is determined via two primary methods—parallax and luminosity. While the parallax is a direct trigonometric method, the luminosity distance is usually influenced by interstellar extinction. As long as the optical properties of dust grains are wavelength-dependent this contamination can be corrected. However, as the grain size increases, the extinction properties become gray, meaning these particles contribute by a constant at wavelengths $\lesssim $ 1 μ m, making them undetectable by photometry in the optical. In this study, we compare the parallactic and luminosity distances of a pristine sample of 33 well-known early-type stars with nonpeculiar reddening curves and find that the luminosity distance overestimates the parallactic distance in 80% of the cases. This discrepancy can be removed when incorporating a population of large, submicrometer-sized dust grains in a dust model that provides gray extinction, which diminishes the luminosity distance accordingly.
ISSN:2041-8205