A gap in the planetesimal disc around HD 107146 and asymmetric warm dust emission revealed by ALMA
A gap in the planetesimal disc around HD 107146 and asymmetric warm dust emission revealed by ALMA
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DOI：
10.1093/mnras/sty1790
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发表时间：
2018-05
影响因子：
4.8
通讯作者：
Sebastián Marino;J. Carpenter;M. Wyatt;M. Booth;S. Casassus;V. Faramaz;V. Guzmán;A. Hughes;A. Isella;Grant M. Kennedy;L. Matrà;L. Ricci;S. Corder
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作者：
Sebastián Marino;J. Carpenter;M. Wyatt;M. Booth;S. Casassus;V. Faramaz;V. Guzmán;A. Hughes;A. Isella;Grant M. Kennedy;L. Matrà;L. Ricci;S. Corder
虽然探测几十个Au的低质量系外行星超出了目前的仪器，但碎片盘提供了研究行星系统外部区域的独特机会。在这里，我们报告了新的阿尔马观测的80-200万年前的太阳类似物HD 107146，揭示了其外柯伊伯带的径向结构在1.1和0.86毫米的波长。我们发现，星子盘是广泛的，从40延伸到140 Au，它的特征是在60 ~ 100 Au范围内有一个环形间隙，在此间隙内连续谱发射下降了约50%。我们还报道了未探测到CO J = 3-2发射线，确认没有足够的气体来影响粉尘分布。迄今为止，HD 107146是唯一一个在毫米级颗粒分布中显示多个环的贫气体系统。这些环表明产生小尘埃颗粒的微行星的类似分布，可以解释为一个或多个扰动行星的存在。由于圆盘是轴对称的，这样的行星应该在圆形轨道上。通过比较N体模拟与观测到的vibrium，我们发现，要解释差距的径向范围和深度，需要存在多个低质量行星或单个行星穿过圆盘。在HD 107146的外柯伊伯带内部，我们发现了扩展的发射，峰值在20 μ m Au处，与之前基于22 μm过量预测的内部暖带一致，就像在许多其他系统中一样。这条暖带是第一个被成像的，尽管出乎意料地表明它是不对称的。这可能是由于一个大的皮带偏心率，或由于cluberous结构产生的共振捕获与一个额外的内行星。
While detecting low-mass exoplanets at tens of au is beyond current instrumentation, debris discs provide a unique opportunity to study the outer regions of planetary systems. Here, we report new ALMA observations of the 80-200 Myr old Solar analogue HD 107146 that reveal the radial structure of its exo-Kuiper belt at wavelengths of 1.1 and 0.86 mm. We find that the planetesimal disc is broad, extending from 40 to 140 au, and it is characterized by a circular gap extending from 60 to 100 au in which the continuum emission drops by about 50 per cent. We also report the non-detection of the CO J = 3-2 emission line, confirming that there is not enough gas to affect the dust distribution. To date, HD 107146 is the only gas-poor system showing multiple rings in the distribution of millimetre sized particles. These rings suggest a similar distribution of the planetesimals producing small dust grains that could be explained invoking the presence of one or more perturbing planets. Because the disc appears axisymmetric, such planets should be on circular orbits. By comparing N-body simulations with the observed visibilities we find that to explain the radial extent and depth of the gap, it would require the presence of multiple low-mass planets or a single planet that migrated through the disc. Interior to HD 107146's exo-Kuiper belt we find extended emission with a peak at ˜20 au and consistent with the inner warm belt that was previously predicted based on 22 μm excess as in many other systems. This warm belt is the first to be imaged, although unexpectedly suggesting that it is asymmetric. This could be due to a large belt eccentricity or due to clumpy structure produced by resonant trapping with an additional inner planet.