B. Stecklum, V. Wolf, J. Eislöffel
Thüringer Landesstwernwarte Tautenburg
Watching massive stars grow with SOFIA
In recent years, the first accretion bursts from massive YSOs (MYSOs) have been detected. This confirmed that episodic accretion, possibly driven by disk instabilities, is a feature of high-mass star formation as well. Since MYSOs are usually deeply embedded, such events are hard to find at near-IR wavelengths. Moreover, the burst-induced flux rise in the (sub)mm is much shallower than in the far-IR, where the peak of the spectral energy distribution is located. Thus, SOFIA observations provide the best prospects to reveal the burst by detecting its FIR emission which, at the same time, provides crucial information on the luminosity increase. Our early results from the first time-dependent radiative transfer modeling of dust continuum emission, applied to this science case, indicate that the burst leads to a thermal afterglow which fades away with a wavelength-dependent time-scale. This implies requirements on the selection and scheduling of SOFIA instruments to follow the evolution of the spectral energy distribution over time. Moreover, since the targets are usually bright, in particular during the burst, sensitivity is no issue. Thus, snapshot measurements would suffice. Establishing a sample of MYSO bursts is mandatory to assess the credibility of corresponding simulations. Moreover, this will lead to better understanding of the burst-induced physical and chemical changes in the protostellar environment.