Issue |
A&A
Volume 692, December 2024
|
|
---|---|---|
Article Number | A69 | |
Number of page(s) | 13 | |
Section | Stellar atmospheres | |
DOI | https://doi.org/10.1051/0004-6361/202452086 | |
Published online | 03 December 2024 |
Measurement of interstellar extinction for classical T Tauri stars using far-UV H2 line fluxes
1
Thüringer Landessternwarte Tautenburg,
Sternwarte 5,
07778
Tautenburg, Germany
2
Hamburger Sternwarte, Universität Hamburg,
Gojenbergsweg 112,
21029
Hamburg, Germany
3
Laboratory for Atmospheric and Space Physics, University of Colorado Boulder,
Boulder, CO
80303, USA
4
European Southern Observatory,
Karl-Schwarzschild-Strasse 2,
85748
Garching bei München, Germany
★ Corresponding author; bfuhrmeister@hs.uni-hamburg.de
Received:
2
September
2024
Accepted:
3
November
2024
Understanding the interstellar and potentially circumstellar extinction in the sight lines of classical T Tauri stars is an important ingredient for constructing reliable spectral energy distributions, which catalyze protoplanetary disk chemistry, for example. Therefore, some attempts of measuring AV toward individual stars have been made using partly different wavelength regimes and different underlying assumptions. We used strong lines of Lyα fluorescent H2 and derived the extinction based on the assumption of optically thin transitions. We investigated a sample of 72 classical T Tauri stars observed with the Hubble Space Telescope in the framework of the ULLYSES program. We computed AV and RV values for the 34 objects with sufficient data quality and an additionally AV value for the canonical RV = 3.1 value. Our results agree largely with values obtained from optical data. Moreover, we confirm the degeneracy between AV and RV and present possibilities to break this. Finally, we discuss whether the assumption of optical thin lines is valid.
Key words: stars: low-mass / stars: pre-main sequence / ultraviolet: stars
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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