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2004MNRAS.347..937L - Mon. Not. R. Astron. Soc., 347, 937-941 (2004/January-3)
Evidence for high accretion rates in weak-line T Tauri stars.
LITTLEFAIR S.P., NAYLOR T., HARRIES T.J., RETTER A. and O'TOOLE S.
Abstract (from CDS):
We propose a scheme to understand these changes whereby the composite spectra of these stars can be explained by a period of active accretion on to the central, young star. In this scheme the composite spectrum consists of a contribution from the stellar photosphere and a contribution from a hot, optically thick, accretion component. The optically thick nature of the accretion flow explains the weakness of the Hα emission during this phase. Within this scheme, the change to a single spectral type at all wavelengths and the emergence of strong Hα emission are consistent with the accretion columns becoming optically thin, as the accretion rate drops. There is a strong analogy here with the dwarf novae class of interacting binaries, which show similar behaviour during the decline from outbursts of high mass transfer rate.
The most important consequence of this interpretation is that these objects bring into question the association of weak-line T Tauri stars with non-accreting or discless objects. In light of this result we consider the justification for this paradigm.
Abstract Copyright: 2004 RAS
Journal keyword(s): accretion, accretion discs - instabilities - stars: dwarf novae - planetary systems: protoplanetary discs - stars: pre-main-sequence
Simbad objects: 9
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