Here we present the Spitzer IRS spectrum of CVSO 224, the sole transitional disk located within the ～10 Myr old 25 Orionis group in Orion OB la. A model fit to the spectral energy distribution of this object indicates a ～7 AU inner disk hole that contains a small amount of optically thin dust. In previous studies, CVSO 224 had been classified as a weak-line T Tauri star based on its Hα equivalent width, but here we find an accretion rate of 7 × 10~(-11) M_☉ yr~(-1) based on high-resolution Hectochelle data. CVSO 224's low M is in line with photoe-vaporative clearing theories. However, the Spitzer IRS spectrum of CVSO 224 has a substantial mid-infrared excess beyond 20 μm which indicates that it is surrounded by a massive outer disk. Millimeter measurements are necessary to constrain the mass of the outer disk around CVSO 224 in order to confirm that photoevaporation is not the mechanism behind creating its inner disk hole.
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机译：在这里，我们介绍了CVSO 224的Spitzer IRS光谱，CVSO 224是位于Orion OB 1a中〜10 Myr old 25 Orionis组中的唯一过渡盘。符合该物体光谱能量分布的模型表明，约有7 AU内盘孔，其中包含少量的光学稀薄尘埃。在先前的研究中，基于CVSO 224的Hα当量宽度将其分类为弱线T Tauri星，但在此我们发现，基于CVSO 224的吸积率为7×10〜（-11）M_☉yr〜（-1）。高分辨率Hectochelle数据。 CVSO 224的低M与光电子蒸发清除理论相一致。但是，CVSO 224的Spitzer IRS光谱具有超过20μm的明显中红外过量，这表明它被巨大的外盘包围。必须进行毫米级测量才能约束CVSO 224周围的外部磁盘质量，以确认光蒸发不是创建其内部磁盘孔的机制。
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