ALMA Discovery of a Disk around the Planetary-mass Companion SR 12 c
ALMA Discovery of a Disk around the Planetary-mass Companion SR 12 c
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DOI：
10.3847/2041-8213/ac6420
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发表时间：
2022-04
期刊：
影响因子：
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通讯作者：
Ya-Lin Wu;B. Bowler;P. Sheehan;L. Close;J. Eisner;W. Best;K. Ward-Duong;Zhaohuan Zhu;A. Kraus
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文献类型：
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作者：
Ya-Lin Wu;B. Bowler;P. Sheehan;L. Close;J. Eisner;W. Best;K. Ward-Duong;Zhaohuan Zhu;A. Kraus
我们报告了阿塔卡马大型毫米/亚毫米阵列0.88 mm（波段7）连续探测SR 12 c周围的吸积盘，SR 12 c是一颗111 M Jup行星质量的伴星（PMC），在980 Au处绕其宿主双星运行。这是第一次在亚毫米波段探测到一个环绕行星的圆盘。尘埃盘的通量密度为127 ± 14 μJy，并且不能被0.0.1 "的光束分辨，因此尘埃盘的半径可能小于5 Au，如果尘埃连续体在光学上很厚，半径可能会小得多。然而，如果尘埃排放是光学薄的，那么SR 12 c盘的尘埃质量与PDS 70 c周围的环行星盘相当，但比自由浮动的OTS 44低约5倍。这表明，围绕着束缚和非束缚行星质量物体的圆盘可以跨越很大的质量范围。以10−11 M yr−1的吸积速率估算的气体质量意味着气尘比高于100。如果云吸收不显著，则未检测到12 CO（3-2）意味着SR 12 c周围存在致密的气盘。未来的敏感观测可能会探测到更多的0.88 mm通量密度为100 μJy的PMC盘。
We report an Atacama Large Millimeter/submillimeter Array 0.88 mm (Band 7) continuum detection of the accretion disk around SR 12 c, an ∼11 M Jup planetary-mass companion (PMC) orbiting its host binary at 980 au. This is the first submillimeter detection of a circumplanetary disk around a wide PMC. The disk has a flux density of 127 ± 14 μJy and is not resolved by the ∼0.″1 beam, so the dust disk radius is likely less than 5 au and can be much smaller if the dust continuum is optically thick. If, however, the dust emission is optically thin, then the SR 12 c disk has a comparable dust mass to the circumplanetary disk around PDS 70 c but is about five times lower than that of the ∼12 M Jup free-floating OTS 44. This suggests that disks around bound and unbound planetary-mass objects can span a wide range of masses. The gas mass estimated with an accretion rate of 10−11 M ☉ yr−1 implies a gas-to-dust ratio higher than 100. If cloud absorption is not significant, a nondetection of 12CO(3–2) implies a compact gas disk around SR 12 c. Future sensitive observations may detect more PMC disks at 0.88 mm flux densities of ≲100 μJy.