Mapping circumstellar magnetic fields of late-type evolved stars with the Goldreich-Kylafis effect: CARMA observations at $\lambda 1.3$ mm of R Crt and R Leo
| Autor: | Louis Yang, Athol J. Kemball, Shih-Ping Lai, Ivan Agudo, Wouter Vlemmings, Ko-Yun Huang |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Physics
010308 nuclear & particles physics Late type Polarimetry Circumstellar masers Astronomy and Astrophysics Astrophysics 01 natural sciences Astrophysics - Astrophysics of Galaxies Magnetic field Stellar magnetic fields Stars Asymptotic giant branch stars Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics CO line emission |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | Mapping magnetic fields is the key to resolving the unclear physical picture of circumstellar magnetic fields in late-type evolved stars. Observations of linearly polarized emission from thermal molecular line transitions due to the Goldreich-Kylafis (G-K) effect provide valuable insights into the magnetic field geometry in these sources that are complementary to other key studies. In this paper, we present the detection of spectral-line polarization from both the thermal J = 2-1 CO line and the v = 1, J = 5-4 SiO maser line toward two thermal-pulsating asymptotic giant branch stars, R Crt and R Leo. The observed fractional linear polarization in the CO emission is measured as m l ∼ 3.1% and m l ∼ 9.7% for R Crt and R Leo, respectively. A circumstellar envelope (CSE) model profile and the associated parameters are estimated and used as input to a more detailed modeling of the predicted linear polarization expected from the G-K effect. The observed thermal line polarization level is consistent with the predicted results from the G-K model for R Crt; additional effects need to be considered for R Leo. © 2020. The American Astronomical Society. All rights reserved. |
| Databáze: | OpenAIRE |
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