Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

Facing the wind of the pre-FUor V1331 Cyg

P. P. Petrov, R. Kurosawa, M. M. Romanova, J. F. Gameiro, M. Fernandez, E. V. Babina, S. A. Artemenko

Abstract
The mass outflows in T Tauri stars (TTS) are thought to be an effective mechanism to remove angular momentum during the pre-main-sequence contraction of a low-mass star. The most powerful winds are observed at the FUor stage of stellar evolution. V1331 Cyg has been considered as a TTS at the pre-FUor stage. We analyse high-resolution spectra of V1331 Cyg collected in 1998–2007 and 20-d series of spectra taken in 2012. For the first time the photospheric spectrum of the star is detected and stellar parameters are derived: spectral type G7–K0 IV, mass 2.8 M, radius 5 R, v sin i < 6 km s−1. The photospheric spectrum is highly veiled, but the amount of veiling is not the same in different spectral lines, being lower in weak transitions and much higher in strong transitions. The Fe ii 5018, Mg i 5183, K i 7699 and some other lines of metals are accompanied by a ‘shell’ absorption at radial velocity of about −240 km s−1. We show that these absorptions form in the post-shock gas in the jet, i.e. the star is seen though its jet. The P Cyg profiles of Hα and Hβ indicate the terminal wind velocity of about 500 km s−1, which vary on time-scales from several days to years. A model of the stellar wind is developed to interpret the observations. The model is based on calculation of hydrogen spectral lines using the radiative transfer code torus. The observed Hα and Hβ line profiles and their variability can be well reproduced with a stellar wind model, where the mass-loss rate and collimation (opening angle) of the wind are variable. The changes of the opening angle may be induced by small variability in magnetization of the inner disc wind. The mass-loss rate is found to vary within (6–11) × 10−8 M yr−1, with the accretion rate of 2.0 × 10−6 M yr−1.

Keywords
stars: individual: V1331 Cyg, stars: variables: T Tauri, Herbig Ae/Be, stars: winds, outflows

Monthly Notices of the Royal Astronomical Society
Volume 442, Page 3643
August 2014

>> PDF>> ADS>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website