X-ray photoevaporation???s limited success in the formation of planetesimals by the streaming instability
Articolo
Data di Pubblicazione:
2017
Citazione:
X-ray photoevaporation???s limited success in the formation of planetesimals by the streaming instability / B. Ercolano, J. Jennings, G. Rosotti, T. Birnstiel. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 472:4(2017), pp. 4117-4125. [10.1093/mnras/stx2294]
Abstract:
The streaming instability is often invoked as solution to the fragmentation and drift barriers in planetesimal formation, catalysing the aggregation of dust on kyr time-scales to grow km-sized cores. However, there remains a lack of consensus on the physical mechanism(s) responsible for initiating it. One potential avenue is disc photoevaporation, wherein the preferential removal of relatively dust-free gas increases the disc metallicity. Late in the disc lifetime, photoevaporation dominates viscous accretion, creating a gradient in the depleted gas surface density near the location of the gap. This induces a local pressure maximum that collects drifting dust particles, which may then become susceptible to the streaming instability. Using a one-dimensional viscous evolution model of a disc subject to internal X-ray photoevaporation, we explore the efficacy of this process to build planetesimals. Over a range of parameters, we find that the amount of dust mass converted into planetesimals is often < 1M(circle plus). and at most a few M-circle plus spread across tens of au. We conclude that photoevaporation may at best be relevant for the formation of debris discs, rather than a common mechanism for the formation of planetary cores. Our results are in contrast to a recent, similar investigation that considered an far-ultra-violet (FUV)driven photoevaporation model and reported the formation of tens of M-circle plus at large (> 100 au) disc radii. The discrepancies are primarily a consequence of the different photoevaporation profiles assumed. Until observations more tightly constrain photoevaporation models, the relevance of this process to the formation of planets remains uncertain.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
planet-disc interactions
Elenco autori:
B. Ercolano, J. Jennings, G. Rosotti, T. Birnstiel
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