Issue |
A&A
Volume 445, Number 1, January I 2006
|
|
---|---|---|
Page(s) | 323 - 329 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20041812 | |
Published online | 13 December 2005 |
The veiling spectrum of DI Cephei and its relationship to emission line profiles
1
Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal e-mail: jgameiro@astro.up.pt
2
Departamento de Matemática Aplicada, Faculdade de Ciências da Universidade do Porto, Portugal
3
Instituto Superior da Maia, Av. Carlos de Oliveira Campos, 4475-690 Avioso S. Pedro, Castelo da Maia, Portugal
4
Crimean Astrophysical Observatory, p/o Nauchny, Crimea, 98409, Ukraine
Received:
6
August
2004
Accepted:
2
September
2005
High spectral resolution variability studies of classical T Tauri stars
(CTTS) are an essential instrument for probing the physical conditions and
dynamics of their atmospheres and immediate vicinity. The shapes of
the excess continuum emission and of the line profiles, their
variability and relationship are all crucial tools to achieve that goal. We
use high spectral resolution optical data of the CTTS DI Cep to suggest
a new diagnostic tool to investigate the relationship between the line
emission/absorption and the excess continuum emission. By correlating
the veiling continuum to the line flux in discrete velocity bins across
the emission line we obtain a correlation profile, from
which one can discriminate between parts of the line that relate
differently to the veiling. An earlier
report of an unexpected hump around 5300 Å in the
continuum excess emission spectrum of a couple of CTTS is
not explained by current models of those stars. We identified a similar
feature in the veiling spectrum of DI Cep and discuss, in this context,
the relevance of the broad photospheric absorption features present in
the spectra of late-type stars. Regarding DI Cep, we find that its
radial velocity seems to be variable but no significant periodicity
could be derived, possibly due to inadequate time sampling. We argue
that this CTTS is most probably observed nearly equator on. Accretion
flows could not be identified directly in the emission lines, but their
presence is inferred from the analysis of the veiling spectrum, which
yields typical projected accretion rates around
yr-1.
Key words: stars: formation / stars: pre-main sequence / stars: individual: DI Cep / methods: data analysis
© ESO, 2005
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