Open AccessMass accretion on to T Tauri stars
Author(s) -
Gregory S. G.,
Jardine M.,
Simpson I.,
Donati J.F.
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10734.x
Subject(s) - physics , accretion (finance) , astrophysics , t tauri star , stars , stellar mass , astronomy , magnetic field , magnetosphere , star formation , quantum mechanics
It is now accepted that accretion on to classical T Tauri stars is controlled by the stellar magnetosphere, yet to date most accretion models have assumed that their magnetic fields are dipolar. By considering a simple steady state accretion model with both dipolar and complex magnetic fields, we find a correlation between mass accretion rate and stellar mass of the form , with our results consistent within observed scatter. For any particular stellar mass there can be several orders of magnitude difference in the mass accretion rate, with accretion filling factors of a few per cent. We demonstrate that the field geometry has a significant effect in controlling the location and distribution of hotspots, formed on the stellar surface from the high velocity impact of accreting material. We find that hotspots are often at mid to low latitudes, in contrast to what is expected for accretion to dipolar fields, and that particularly for higher mass stars, the accretion flow is predominantly carried by open field lines.