2008/11/19 by A. Pereyra, A. M. Magalhães, F. X. de Araújo · 3 citations
Chemistry · Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Asymmetry #Linear polarization #Molecular Spectroscopy and Structure #Optics #Physics #Polarization (electrochemistry) #Position angle #Protoplanetary disk #Spectral line #Stars #Stellar, planetary, and galactic studies #T Tauri star #astro-ph
paper · pdf · doi:10.1051/0004-6361:200810467
published in Astronomy and Astrophysics 495(1), 195-199 (EDP Sciences) · 6 pages, 5 figures. Accepted for publication in Astronomy and Astrophysics
arxiv created 2008/11/19 · openalex publication_date 2009/01/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
<i>Aims. <i/>To detect line effects using spectropolarimetry in order to find evidence of rotating disks and their respective symmetry axes in T Tauri stars.<i>Methods. <i/>We used the IAGPOL imaging polarimeter along with the Eucalyptus-IFU to obtain spectropolarimetric measurements of the T Tauri stars RY Tau (two epochs) and PX Vul (one epoch). Evidence of line effects showing a loop in the <i>Q<i/>-<i>U<i/> diagram favors a compact rather than an extended source for the line photons in a rotating disk. In addition, the polarization position angle (PA) obtained using the line effect can constrain the symmetry axis of the disk.<i>Results. <i/>RY Tau shows a variable H<i>α<i/> double peak in 2004-2005 data. A polarization line effect is evident in the <i>Q<i/>-<i>U<i/> diagram for both epochs confirming a clockwise rotating disk. A single loop is evident in 2004 changing to a linear excursion plus a loop in 2005. Interestingly, the intrinsic PA calculated using the line effect is consistent between our two epochs (~167°). An alternative intrinsic PA computed from the interstellar polarization-corrected continuum and averaged between 2001-2005 yielded a PA ~ 137°. This last value is closer to perpendicular to the observed disk direction (~25°), as expected from single scattering in an optically thin disk. For PX Vul, we detected spectral variability in H<i>α<i/> along with non-variable continuum polarization when compared with previous data. The <i>Q<i/>-<i>U<i/> diagram shows a well-defined loop in H<i>α<i/> associated with a counter-clockwise rotating disk. The symmetry axis inferred from the line effect has a PA ~ 91°(with an ambiguity of 90°). Our results confirm previous evidence that the emission line in T Tauri stars has its origin in a compact source scattered off a rotating accretion disk.