Title
Hα spectropolarimetry of RY Tauri and PX Vulpeculae
Date Issued
01 February 2009
Access level
open access
Resource Type
journal article
Author(s)
Magalhães A.
De Araújo F.
Observatório Nacional
Abstract
Aims. To detect line effects using spectropolarimetry in order to find evidence of rotating disks and their respective symmetry axes in T Tauri stars.Methods. 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 Q-U 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.Results. RY Tau shows a variable Hα double peak in 2004-2005 data. A polarization line effect is evident in the Q-U 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 Hα along with non-variable continuum polarization when compared with previous data. The Q-U diagram shows a well-defined loop in Hα 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. © 2009 ESO.
Start page
195
End page
199
Volume
495
Issue
1
Language
English
OCDE Knowledge area
Astronomía
Scopus EID
2-s2.0-60849139462
Source
Astronomy and Astrophysics
ISSN of the container
14320746
Sources of information: Directorio de Producción Científica Scopus