这是节选某篇学术论文：
In this Letter, we present high-resolution (50 au) observations of continuum (1.3 and 3 mm) and molecular (CH3OH, H2CO and SiO) emission towards the CrA cluster in the context of the ALMA FAUST LP. Our analysis indicates that SMM 1A, previously identified as an extended continuum structure, is associated with a shock driven by IRS7B, and mapped in CH3OH, H2CO, and SiO, and with a conical dusty cavity opened by the mass-loss process. We estimated the H2 column density (∼7×1021 cm−2 ) and mass (∼9×10−3 M⊙) in the cavity walls, and a lower limit for the dust spectral index (α > 1.4), which could imply the presence of millimetre-sized grains. Based on these results, we conclude that the CrA cluster may be a unique laboratory with which to investigate and test models of dust grain growth in the envelope. Additional higher-sensitivity and higher-resolution observations of shock tracers, such as SiO and CO, are needed to reveal the IRS7B jet. The discovery of a twin system in IRS7B (Ohashi et al. 2023) opens the possibility that there are two jets. Therefore, the SiO knot could be due to precession. Further mapping of CH3OH emission in the SW region around SMM 1A and beyond the FAUST FoV is also needed to reveal additional interactions between the jet and the CrA envelope on a larger scale; our Band-3 maps already suggest their existence. This would allow us to determine the extent to which the jet influences the chemical composition of the CrA cluster. Ultimately, a more accurate estimate of α will be made possible with more sensitive observations at longer wavelengths, allowing us to constrain the properties and size distribution of the dust grains in the cavity walls and to probe for the formation and/or entrainment of large grains in the envelope。
In this Letter, we present high-resolution (50 au) observations of continuum (1.3 and 3 mm) and molecular (CH3OH, H2CO and SiO) emission towards the CrA cluster in the context of the ALMA FAUST LP. Our analysis indicates that SMM 1A, previously identified as an extended continuum structure, is associated with a shock driven by IRS7B, and mapped in CH3OH, H2CO, and SiO, and with a conical dusty cavity opened by the mass-loss process. We estimated the H2 column density (∼7×1021 cm−2 ) and mass (∼9×10−3 M⊙) in the cavity walls, and a lower limit for the dust spectral index (α > 1.4), which could imply the presence of millimetre-sized grains. Based on these results, we conclude that the CrA cluster may be a unique laboratory with which to investigate and test models of dust grain growth in the envelope. Additional higher-sensitivity and higher-resolution observations of shock tracers, such as SiO and CO, are needed to reveal the IRS7B jet. The discovery of a twin system in IRS7B (Ohashi et al. 2023) opens the possibility that there are two jets. Therefore, the SiO knot could be due to precession. Further mapping of CH3OH emission in the SW region around SMM 1A and beyond the FAUST FoV is also needed to reveal additional interactions between the jet and the CrA envelope on a larger scale; our Band-3 maps already suggest their existence. This would allow us to determine the extent to which the jet influences the chemical composition of the CrA cluster. Ultimately, a more accurate estimate of α will be made possible with more sensitive observations at longer wavelengths, allowing us to constrain the properties and size distribution of the dust grains in the cavity walls and to probe for the formation and/or entrainment of large grains in the envelope。
