On the Nature of the Extended Radio Emission Surrounding T Tauri South
| Autor: | Laurent Loinard, Mónica I. Rodríguez, Ricardo F. González, Luis F. Rodríguez, Paola D'Alessio |
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| Rok vydání: | 2007 |
| Předmět: |
Physics
Infrared Star formation Astronomy Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Stars T Tauri star Space and Planetary Science Ionization Astrophysics::Solar and Stellar Astrophysics Spectral energy distribution Astrophysics::Earth and Planetary Astrophysics Halo Circumbinary planet Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 657:916-924 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1086/510994 |
| Popis: | At centimeter wavelengths, the young stellar system T Tauri is known to be composed of two sources, the northern one associated with the optical star T Tau itself, and the southern one related to the infrared companion T Tau S. Here wereexaminetheoriginoftheradioemissionfromthesetwocomponentsusingarchival2cm,3.6cm,and6cmVLA observations. The emission from the northern member is confirmed to be largely dominated by free-free radiation from an ionized wind, while the southern radio source is confirmed to consist of a compact component of magnetic origin, surrounded by an extended halo. Only moderately variable, the extended structure associated with the southern source is most likely the result of free-free radiation related to stellar winds. However, its flat spectral energy distribution,its extent,andthelackofvariationof itssizewiththefrequencyofobservationareincompatiblewiththe classical picture of a fully ionized wind with constant velocity and mass-loss rate leading to an electron density distribution of ne(r) / r � 2 . Instead, we propose a model in which the ionization results from the impact of a supersonic wind driven by T Tau Sb onto dense surrounding material, possibly associated with the circumbinary disk recently identified around the T Tau Sa/T Tau Sb pair. The timescales for cooling and recombination in such a situation are in good agreement with the observed morphological changes undergone by the extended structure as its driving source moves through the environment. Subject headings: binaries: general — ISM: jets and outflows — radiation mechanisms: general — radio continuum: stars — stars: formation |
| Databáze: | OpenAIRE |
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