Search for grain growth towards the center of L1544
Search for grain growth towards the center of L1544
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DOI：
10.1051/0004-6361/201630265
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发表时间：
2017-06
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通讯作者：
A. Chac'on-Tanarro;P. Caselli;L. Bizzocchi;J. Pineda;J. Harju;M. Spaans;F. I. F. Physik-F.-I.-F.-Physik-103024816;H Germany;D. Physics;U. Helsinki;Finland.;K. Institute;U. Groningen;The Netherlands.;U. G. Alpes;Cnrs;Ipag;France.
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作者：
A. Chac'on-Tanarro;P. Caselli;L. Bizzocchi;J. Pineda;J. Harju;M. Spaans;F. I. F. Physik-F.-I.-F.-Physik-103024816;H Germany;D. Physics;U. Helsinki;Finland.;K. Institute;U. Groningen;The Netherlands.;U. G. Alpes;Cnrs;Ipag;France.
在密集而寒冷的分子云中，尘埃颗粒被厚厚的冰幔所包围。然而，尚不清楚尘埃的生长和凝结是否发生在原恒星开启之前。这是一个重要的问题，因为大颗粒的存在可能会影响致密云核的化学结构，包括动态重要的电离分数，以及原行星盘中固体的未来演变。为了进一步研究这一点，我们将重点放在L1544上，它是星星形成边缘最集中的前恒星核心之一，具有众所周知的物理结构。我们观察L1544在1.2和2毫米使用NIKA，一个新的接收器在IRAM 30米望远镜，我们使用的数据从赫歇尔空间天文台档案。我们没有发现任何证据的晶粒生长的中心L1544在可用的角分辨率。因此，我们得出结论，单碟观测不允许我们调查晶粒生长的前恒星核心L1544和高灵敏度的干涉仪观测是必要的。我们预测，尘埃颗粒可以增长到200 $\mu$m的大小对中央~300 Au的L1544。这意味着在1.2 mm处尘埃不透明度变化约为2.5倍，可以使用阿塔卡马大型毫米和亚毫米阵列（阿尔马）在不同波长和2”的角分辨率下进行检测。
In dense and cold molecular clouds dust grains are surrounded by thick icy mantles. It is however not clear if dust growth and coagulation take place before the switch-on of a protostar. This is an important issue, as the presence of large grains may affect the chemical structure of dense cloud cores, including the dynamically important ionization fraction, and the future evolution of solids in protoplanetary disks. To study this further, we focus on L1544, one of the most centrally concentrated pre-stellar cores on the verge of star formation, and with a well-known physical structure. We observed L1544 at 1.2 and 2 mm using NIKA, a new receiver at the IRAM 30 m telescope, and we used data from the Herschel Space Observatory archive. We find no evidence of grain growth towards the center of L1544 at the available angular resolution. Therefore, we conclude that single dish observations do not allow us to investigate grain growth toward the pre-stellar core L1544 and high sensitivity interferometer observations are needed. We predict that dust grains can grow to 200 $\mu$m in size toward the central ~300 au of L1544. This will imply a dust opacity change by a factor of ~2.5 at 1.2 mm, which can be detected using the Atacama Large Millimeter and submillimeter Array (ALMA) at different wavelengths and with an angular resolution of 2".