Spatially resolving the hot CO around the young Be star 51 Ophiuchi
Tatulli, E; Malbet, F; Ménard, F; et al.Gil, C; Testi, L; Natta, A; Kraus, S; Stee, P; Robbe-Dubois, S
Date: 1 October 2008
Journal
Astronomy and Astrophysics
Publisher
EDP Sciences for European Southern Observatory (ESO)
Publisher DOI
Abstract
Aims. 51 Oph is one of the few young Be stars displaying a strong CO overtone emission at 2.3 microns in addition to the near
infrared excess commonly observed in this type of stars. In this paper we first aim to locate the CO bandheads emitting region. Then,
we compare its position with respect to the region emitting the near infrared ...
Aims. 51 Oph is one of the few young Be stars displaying a strong CO overtone emission at 2.3 microns in addition to the near
infrared excess commonly observed in this type of stars. In this paper we first aim to locate the CO bandheads emitting region. Then,
we compare its position with respect to the region emitting the near infrared continuum.
Methods. We have observed 51 Oph with AMBER in low spectral resolution (R=35), and in medium spectral resolution (R=1500)
centered on the CO bandheads.
Results. The medium resolution AMBER observations clearly resolve the CO bandheads. Both the CO bandheads and continuum
emissions are spatially resolved by the interferometer. Using simple analytical ring models to interpret the measured visibilities, we
find that the CO bandheads emission region is compact, located at 0.150.07
−0.04AU from the star, and that the adjacent continuum is
coming from a region further away (0.250.06
−0.03AU). These results confirm the commonly invoked scenario in which the CO bandheads
originate in a dust free hot gaseous disk. Furthermore, the continuum emitting region is closer to the star than the dust sublimation
radius (by at least a factor two) and we suggest that hot gas inside the dust sublimation radius significantly contributes to the observed
2 µm continuum emission
Physics and Astronomy
Faculty of Environment, Science and Economy
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