Details

Autor(en) / Beteiligte

• CHIAVASSA, A
• PLEZ, B
• JOSSELIN, E
• FREYTAG, B

Titel

Radiative hydrodynamics simulations of red supergiant stars I. interpretation of interferometric observations

Ist Teil von

• Astronomy and astrophysics (Berlin), 2009-11, Vol.506 (3), p.1351-1365

Ort / Verlag

Les Ulis: EDP Sciences

Erscheinungsjahr

2009

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Context. It has been proposed that convection in red supergiant (RSG) stars produces large-scale granules causing observable surface inhomogeneities. This convection is also extremely vigorous and is suspected to be one of the main causes of mass-loss in RSGs. It should thus be understood in detail. Evidence has accumulated of asymmetries in the photospheres of RSGs, but detailed studies of granulation are still lacking. Interferometric observations provide an innovative way of addressing this question, but they are still often interpreted using smooth symmetrical limb-darkened intensity distributions, or simple, spotted, ad hoc models. Aims. We explore the impact of the granulation on visibility curves and closure phases using the radiative transfer code OPTIM3D. We simultaneously assess how 3D simulations of convection in RSG with (COBOLD)-B-5 can be tested by comparing with these observations. Methods. We use 3D radiative hydrodynamical (RHD) simulations of convection to compute intensity maps at various wavelengths and time, from which we derive interferometric visibility amplitudes and phases. We study their behaviour with time, position angle, and wavelength, and compare them to observations of the RSG alpha Ori. Results. We provide average limb-darkening coefficients for RSGs. We describe the prospects for the detection and characterization of granulation (i.e., contrast, size) on RSGs. We demonstrate that our RHD simulations provide an excellent fit to existing interferometric observations of alpha Ori, in contrast to limb darkened disks. This confirms the existence of large convective cells on the surface of Betelgeuse.