Observing the hot gas and dust in the close circumstellar environment of
young stars with spectro-interferometry.
Eric TATULLI
LAOG
Résumé :
Observing the protoplanetary disks around young stars is a key issue to
understand the first steps of stellar and planet formation mechanisms.
Such processes are occurring in the very inner environment of the central
star, at distances of a few Astronomical Units or less. Typical
observational clues of such objects are twofold:
(i) a continuum infrared excess of the SED, that usually arises from the
thermal emission of the surrounding circumstellar dust, and
(ii) emission (/absorption) lines that can originate whether from
magnetospheric accretion, magnetically-driven outflows and/or from the
rotating gaseous disk itself.
In order to characterize these mechanisms unambiguously, one needs both
spatial and spectral resolution to localize and separate the continuum
and line emission regions. At distances of the first stellar formation
regions (150pc), 1AU corresponds to a angular distance of 6 mas, a
resolution that only interferometric techniques can achieve. As a
result, near infrared spectro-interferometry, which provides both the
spatial and spectral resolution required, appears to be a technique
perfectly suited to unveil the origin of the continuum and line emission
regions. In this presentation, I will focus on observations performed
with the VLTI/AMBER recombiner, showing how such type of instrument can
efficiently probe both the hot dust and gas around young stars.
