论文标题
在较高的温度下，在原星盘上向内漂流
Drifting inwards in protoplanetary discs I Sticking of chondritic dust at increasing temperatures
论文作者
论文摘要
粘性特性统治着卵石生长的早期卵石生长在原星盘中，谷物经常从寒冷，水丰富的区域传播到温暖的内部。由于谷物的温度越高，这种漂移会影响成分，晶粒尺寸，形态和水含量。在这项研究中，我们在1400 k的真空下恢复了软骨灰尘。之后，我们测量了毫米尺寸的灰尘聚集体的拉伸强度。推导的有效表面能开始于$γ_e= 0.07 \，\ rm j/m^2 $。通过Mössbauer光谱法测量，该值由丰富的铁氧化物主导。高达1250 K，$γ_E$不断减小到第五。橄榄石在较高温度下占主导地位。超过1300 k的灰尘晶粒的尺寸显着增长。 $γ_E$不再减少，但较大的晶粒尺寸限制了生长骨料的能力。超过1400 K的聚合是不再可能的。总体而言，在探测的条件下，灰尘卵石的稳定性将降低到恒星上。鉴于触发阻力不稳定性所需的最小骨料大小，它变得越来越难以接近恒星的种子行星形成。
Sticking properties rule the early phases of pebble growth in protoplanetary discs in which grains regularly travel from cold, water-rich regions to the warm inner part. This drift affects composition, grain size, morphology, and water content as grains experience ever higher temperatures. In this study we tempered chondritic dust under vacuum up to 1400 K. Afterwards, we measured the splitting tensile strength of millimetre-sized dust aggregates. The deduced effective surface energy starts out as $γ_e = 0.07\,\rm J/m^2$. This value is dominated by abundant iron-oxides as measured by Mössbauer spectroscopy. Up to 1250 K, $γ_e$ continuously decreases by up to a factor five. Olivines dominate at higher temperature. Beyond 1300 K dust grains significantly grow in size. The $γ_e$ no longer decreases but the large grain size restricts the capability of growing aggregates. Beyond 1400 K aggregation is no longer possible. Overall, under the conditions probed, the stability of dust pebbles would decrease towards the star. In view of a minimum aggregate size required to trigger drag instabilities it becomes increasingly harder to seed planetesimal formation closer to a star.
