Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolutionary constraints on the planetary hypothesis for transition
  discs   We assume a scenario in which transition discs (i.e. discs around young stars
that have signatures of cool dust but lack significant near infra-red emission
from warm dust) are associated with the presence of planets (or brown dwarfs).
These are assumed to filter the dust content of any gas flow within the
planetary orbit and produce an inner `opacity hole'. In order to match the
properties of transition discs with the largest (~50 A.U. scale) holes, we
place such `planets' at large radii in massive discs and then follow the
evolution of the tidally coupled disc-planet system, comparing the system's
evolution in the plane of mm flux against hole radius with the properties of
observed transition discs. We find that, on account of the high disc masses in
these systems, all but the most massive `planets' (100 Jupiter masses) are
conveyed to small radii by Type II migration without significant fading at
millimetre wavelengths. Such behaviour would contradict the observed lack of mm
bright transition discs with small (<10 A.U.) holes. On the other hand, imaging
surveys clearly rule out the presence of such massive companions in transition
discs. We conclude that this is a serious problem for models that seek to
explain transition discs in terms of planetary companions unless some mechanism
can be found to halt inward migration and/or suppress mm flux production. We
suggest that the dynamical effects of substantial accretion on to the
planet/through the gap may offer the best prospect for halting such migration
but that further long term simulations are required to clarify this issue.

33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph