Orbital variability of the optical linear polarization of the γ-ray binary LS I +61° 303 and new constraints on the orbital parameters
| Autor: | Maria Chernyakova, Takeshi Sakanoi, Vadim Kravtsov, Vilppu Piirola, Sergey S. Tsygankov, Svetlana V. Berdyugina, Ilia A. Kosenkov, Juri Poutanen, Denys Malyshev, Andrei Berdyugin, Masato Kagitani |
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| Rok vydání: | 2020 |
| Předmět: |
Orbital plane
010504 meteorology & atmospheric sciences Astrophysics::High Energy Astrophysical Phenomena Astrophysics 01 natural sciences symbols.namesake 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Stokes parameters Circular orbit 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Physics Orbital elements Linear polarization Astrophysics::Instrumentation and Methods for Astrophysics Astronomy and Astrophysics Position angle Polarization (waves) Orbital period Astrophysics - Solar and Stellar Astrophysics 13. Climate action Space and Planetary Science symbols Astrophysics::Earth and Planetary Astrophysics Astrophysics - High Energy Astrophysical Phenomena |
| Zdroj: | Astronomy & Astrophysics. 643:A170 |
| ISSN: | 1432-0746 0004-6361 |
| Popis: | We studied the variability of the linear polarization and brightness of the $\gamma$-ray binary LS I +61 303. High-precision BVR photopolarimetric observations were carried out with the Dipol-2 polarimeter on the 2.2 m remotely controlled UH88 telescope at Mauna Kea Observatory and the 60 cm Tohoku telescope at Haleakala Observatory (Hawaii) over 140 nights in 2016--2019. We determined the position angle of the intrinsic polarization $\theta \simeq 11^\circ$, which can either be associated with the projection of the Be star's decretion disk axis on the plane of sky, or can differ from it by $90^\circ$. Using the Lomb-Scargle method, we performed timing analyses and period searches of our polarimetric and photometric data. We found statistically significant periodic variability of the normalized Stokes parameters $q$ and $u$ in all passbands. The most significant period of variability, $P_\text{Pol} = 13.244 \pm 0.012$ d, is equal to one half of the orbital period $P_\text{orb} = 26.496$ d. Using a model of Thomson scattering by a cloud that orbits the Be star, we obtained constraints on the orbital parameters, including a small eccentricity $e Comment: 15 pages, 16 figures, accepted for publication in A&A |
| Databáze: | OpenAIRE |
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