论文标题
在空间上解决行星构建块的化学成分
Spatially resolving the chemical composition of the planet building blocks
论文作者
论文摘要
原球盘的内部区域（从$ \ sim $ 0.1到10 au）是行星的预期出生地，尤其是telluric。在那些高温区域，固体可以经历周期性退火，蒸发和恢复。热和温暖的尘土谷物主要在红外域中散发出来，尤其是在N波段（8至13〜 $μ$ m）。通过新的VLTI仪器Matisse通过中红外的光谱互动来研究其精细的化学，可以在空间上解决这些区域，这需要详细的粉尘化学模型。使用辐射转移，我们得出了具有不同内盘（$ <1 $ au）灰尘组成的基准静态原球盘模型的红外光谱。后者源自以LTE计算的三个初始$ c/o $比率计算的冷凝序列：sustolar（$ c/o = 0.4 $），太阳能（$ c/o = 0.54 $）和supersolar（$ c/o = 1 $）。这三种情况返回了非常不同的N波段光谱，尤其是在考虑存在亚微米大小的尘埃谷物时。 Matisse应该能够检测这些差异并追踪相关的子AU级径向变化。我们提出了对三个Herbig Star（HD142527，HD144432，HD163296）和一名TAuri Star（AS209）获得的前VLTI仪器MIDI获得的N波段“内盘”光谱的首次解释。值得注意的是，我们可以将HD142527的Superall（富含碳富含碳）组成与HD1444432相关联（富含氧气富含氧气）。我们表明，内盘矿物学可能非常具体，并且与从空间未解决的中红外光谱中得出的灰尘组成无关。我们强调需要在解释椎间盘内部区域的固态光谱观测以及考虑未来研究的动态方面时，需要包括更复杂的化学反应。
The inner regions of protoplanetary discs (from $\sim$ 0.1 to 10 au) are the expected birthplace of planets, especially telluric. In those high temperature regions, solids can experience cyclical annealing, vaporisation and recondensation. Hot and warm dusty grains emits mostly in the infrared domain, notably in N-band (8 to 13~$μ$m). Studying their fine chemistry through mid-infrared spectro-interferometry with the new VLTI instrument MATISSE, which can spatially resolve these regions, requires detailed dust chemistry models. Using radiative transfer, we derived infrared spectra of a fiducial static protoplanetary disc model with different inner disc ($< 1$ au) dust compositions. The latter were derived from condensation sequences computed at LTE for three initial $C/O$ ratios: subsolar ($C/O=0.4$), solar ($C/O=0.54$), and supersolar ($C/O=1$). The three scenarios return very different N-band spectra, especially when considering the presence of sub-micron-sized dust grains. MATISSE should be able to detect these differences and trace the associated sub-au-scale radial changes. We propose a first interpretation of N-band `inner-disc' spectra obtained with the former VLTI instrument MIDI on three Herbig stars (HD142527, HD144432, HD163296) and one T Tauri star (AS209). Notably, we could associate a supersolar (`carbon-rich') composition for HD142527 and a subsolar (`oxygen-rich') one for HD1444432. We show that the inner disc mineralogy can be very specific and not related to the dust composition derived from spatially unresolved mid-infrared spectroscopy. We highlight the need for including more complex chemistry when interpreting solid-state spectroscopic observations of the inner regions of discs, and for considering dynamical aspects for future studies.
