Publications of the MPIfR Optical & Infrared Interferometry Group

MWC 297

1) Disk and wind interaction in the young stellar object MWC 297 spatially resolved with AMBER/VLTI

F. Malbet, M. Benisty, W.-J. de Wit, S. Kraus, A. Meilland, F. Millour, E. Tatulli, J.-P. Berger, O. Chesneau, K.-H. Hofmann, A. Isella, A. Natta, R.G. Petrov, T. Preibisch, P. Stee, L. Testi, G. Weigelt, P. Antonelli, U. Beckmann, Y. Bresson, A. Chelli, M. Dugué, G. Duvert, S. Gennari, L. Glück, P. Kern, S. Lagarde, E. Le Coarer, F. Lisi, K. Perraut, P. Puget, F. Rantakyrö, S. Robbe-Dubois, A. Roussel, G. Zins, M. Accardo, B. Acke, K. Agabi, E. Altariba, B. Arezki, E. Aristidi, C. Baffa, J. Behrend, T. Blöcker, S. Bonhomme, S. Busoni, F. Cassaing, J.-M. Clausse, J. Colin, C. Connot, A. Delboulbé, A. Domiciano de Souza, T. Driebe, P. Feautrier, D. Ferruzzi, T. Forveille, E. Fossat, R. Foy, D. Fraix-Burnet, A. Gallardo, E. Giani, C. Gil, A. Glentzlin, M. Heiden, M. Heininger, O. Hernandez Utrera, D. Kamm, M. Kiekebusch, D. Le Contel, J.-M. Le Contel, T. Lesourd, B. Lopez, M. Lopez, Y. Magnard, A. Marconi, G. Mars, G. Martinot-Lagarde, P. Mathias, P. Mège, J.-L. Monin, D. Mouillet, D. Mourard, E. Nussbaum, K. Ohnaka, J. Pacheco, C. Perrier, Y. Rabbia, S. Rebattu, F. Reynaud, A. Richichi, A. Robini, M. Sacchettini, D. Schertl, M. Schöller, W. Solscheid, A. Spang, P. Stefanini, M. Tallon, I. Tallon-Bosc, D. Tasso, F. Vakili, O. von der Lühe, J.-C. Valtier, M. Vannier, and N. Ventura

Astronomy & Astrophysics, vol.464, pg.43-53 (2007)

Abstract
The young stellar object MWC 297 is an embedded B1.5Ve star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has been observed with the VLT interferometer equipped with the AMBER instrument during its first commissioning run. AMBER/VLTI is currently the only near infrared interferometer that can observe spectrally dispersed visibilities. MWC 297 has been spatially resolved in the continuum with a visibility of 0.50+0.08-0.10 as well as in the Br$\gamma$ emission line where the visibility decreases to $0.33\pm0.06$. This change in the visibility with wavelength can be interpreted by the presence of an optically thick disk responsible for the visibility in the continuum and of a stellar wind traced by the Br$\gamma$ emission line and whose apparent size is 40% larger. We validate this interpretation by building a model of the stellar environment that combines a geometrically thin, optically thick accretion disk model consisting of gas and dust, and a latitude-dependent stellar wind outflowing above the disk surface. The continuum emission and visibilities obtained from this model are fully consistent with the interferometric AMBER data. They agree also with existing optical, near-infrared spectra and other broad-band near-infrared interferometric visibilities. We also reproduce the shape of the visibilities in the Br$\gamma$ line as well as the profile of this line obtained at an higher spectral resolution with the VLT/ISAAC spectrograph, and those of the H$\alpha$ and H$\beta$ lines. The disk and wind models yield a consistent inclination of the system of approximately 20°. A picture emerges in which MWC 297 is surrounded by an equatorial flat disk that is possibly still accreting and an outflowing wind that has a much higher velocity in the polar region than at the equator. The AMBER/VLTI unique capability of measuring spectral visibilities therefore allows us for the first time to compare the apparent geometry of a wind with the disk structure in a young stellar system.

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2) Constraining the wind launching region in Herbig Ae stars: AMBER/VLTI spectroscopy of HD 104237

E. Tatulli, A. Isella, A. Natta, L. Testi, A. Marconi, F. Malbet, P. Stee, R.G. Petrov, F. Millour, A. Chelli, G. Duvert, P. Antonelli, U. Beckmann, Y. Bresson, M. Dugué, S. Gennari, L. Glück, P. Kern, S. Lagarde, E. Le Coarer, F. Lisi, K. Perraut, P. Puget, F. Rantakyrö, S. Robbe-Dubois, A. Roussel, G. Weigelt, G. Zins, M. Accardo, B. Acke, K. Agabi, E. Altariba, B. Arezki, E. Aristidi, C. Baffa, J. Behrend, T. Blöcker, S. Bonhomme, S. Busoni, F. Cassaing, J.-M. Clausse, J. Colin, C. Connot, A. Delboulbé, A. Domiciano de Souza, T. Driebe, P. Feautrier, D. Ferruzzi, T. Forveille, E. Fossat, R. Foy, D. Fraix-Burnet, A. Gallardo, E. Giani, C. Gil, A. Glentzlin, M. Heiden, M. Heininger, O. Hernandez Utrera, K.-H. Hofmann, D. Kamm, M. Kiekebusch, S. Kraus, D. Le Contel, J.-M. Le Contel, T. Lesourd, B. Lopez, M. Lopez, Y. Magnard, G. Mars, G. Martinot-Lagarde, P. Mathias, P. Mège, J.-L. Monin, D. Mouillet, D. Mourard, E. Nussbaum, K. Ohnaka, J. Pacheco, C. Perrier, Y. Rabbia, S. Rebattu, F. Reynaud, A. Richichi, A. Robini, M. Sacchettini, D. Schertl, M. Schöller, W. Solscheid, A. Spang, P. Stefanini, M. Tallon, I. Tallon-Bosc, D. Tasso, F. Vakili, O. von der Lühe, J.-C. Valtier, M. Vannier, and N. Ventura

Astronomy & Astrophysics, vol.464, pg.55-58 (2007)

Abstract
Aims.We investigate the origin of the ${\rm Br}\gamma$ emission of the Herbig Ae star HD 104237 on Astronomical Unit (AU) scales.
Methods.Using AMBER/VLTI at a spectral resolution $\mathcal{R}=1500$ we spatially resolve the emission in both the ${\rm Br}\gamma$ line and the adjacent continuum.
Results.The visibility does not vary between the continuum and the ${\rm Br}\gamma$ line, even though the line is strongly detected in the spectrum, with a peak intensity 35% above the continuum. This demonstrates that the line and continuum emission have similar size scales. We assume that the K-band continuum excess originates in a "puffed-up" inner rim of the circumstellar disk, and discuss the likely origin of  ${\rm Br}\gamma$.
Conclusions.We conclude that this emission most likely arises from a compact disk wind, launched from a region 0.2-0.5 AU from the star, with a spatial extent similar to that of the near infrared continuum emission region, i.e., very close to the inner rim location.

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