Speaker
Description
We present radiative transfer modeling of the 1.3 mm dust-continuum emission in the Class 0 protostar IRAS 04166+2706, observed as part of the ALMA Large Program ``Early Planet Formation in Embedded Disks (eDisk).'' Using the radiative transfer code RADMC-3D, we construct disk models characterized by an exponential-taper surface density profile, which describes the radial distribution of dust in the disk through six key parameters, including the mass accretion rate $\dot{M}$, the disk mass $M_{\rm disk}$, the characteristic radius $R_w$, the inner and outer power-law indices $\gamma_1$ and $\gamma_2$, and the flaring index $q$. We perform a systematic parameter search of more than 200 models, exploring a wide range of discrete values for these six parameters to identify the best-fit model and to investigate the sensitivity of the dust-continuum morphology to each parameter. Our best-fit model adopts $\dot{M} = 1.4 \times 10^{-7} M_\odot$ yr$^{-1}$, $M_{\rm disk} = 0.075 M_\odot$, $R_w = 0.10''$, and $q = 0.30$ without good constraint on $\gamma_1$ and $\gamma_2$ successfully reproduces the observed peak intensity of $\sim$9.6 mJy beam$^{-1}$ and the asymmetric brightness distribution along the disk minor axis. We find that viscous accretion heating is essential for reproducing the observed peak brightness temperature of $\sim$133 K, as passive stellar irradiation alone is insufficient even at the highest tested disk mass. This is only the second demonstration in a protostellar disk following the Class I source R CrA IRS 7B-a (Takakuwa et al. 2024), and notably the first for a Class 0 source, suggesting that viscous heating is common in protostellar disks. Our parameter study reveals a clear hierarchy in shaping the dust-continuum morphology: the mass accretion rate and disk mass dominate the peak intensity, the characteristic radius governs the radial profile shape, and the flaring index controls the minor-axis asymmetry. These results lay the groundwork for systematic modeling of protostellar disk morphologies in current and future ALMA observations.
| Participate the oral/poster presentation award competition | Yes |
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