Dust unveils the formation of a mini-Neptune planet in a protoplanetary ring. (arXiv:1902.05143v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Perez_S/0/1/0/all/0/1">Sebastián Pérez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casassus_S/0/1/0/all/0/1">Simon Casassus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baruteau_C/0/1/0/all/0/1">Clément Baruteau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dong_R/0/1/0/all/0/1">Ruobing Dong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hales_A/0/1/0/all/0/1">Antonio Hales</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cieza_L/0/1/0/all/0/1">Lucas Cieza</a>
Rings and radial gaps are ubiquitous in protoplanetary disks, yet their
possible connection to planet formation is currently subject to intense
debates. In principle, giant planet formation leads to wide gaps which separate
the gas and dust mass reservoir in the outer disk, while lower mass planets
lead to shallow gaps which are manifested mainly on the dust component. We used
the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the star
HD169142, host to a prominent disk with deep wide gaps that sever the disk into
inner and outer regions. The new ALMA high resolution images allow for the
outer ring to be resolved as three narrow rings. The HD169142 disk thus hosts
both the wide gaps trait of transition disks and a narrow ring system similar
to those observed in the TW Hya and HL Tau systems. The mass reservoir beyond a
deep gap can thus host ring systems. The observed rings are narrow in radial
extent (width/radius of 1.5/57.3, 1.8/64.2 and 3.4/76.0, in au) and have
asymmetric mutual separations: the first and middle ring are separated by 7 au
while the middle and outermost ring are distanced by ~12 au. Using
hydrodynamical modeling we found that a simple explanation, involving a single
migrating low mass planet (10 M$_oplus$), entirely accounts for such an
apparently complex phenomenon. Inward migration of the planet naturally
explains the ring’s asymmetric mutual separation. The isolation of HD169142’s
outer rings thus allows a proof of concept to interpret the detailed
architecture of the outer region of protoplanetary disks with low mass planet
formation of mini-Neptune’s size, i.e. as in the protosolar nebula.
Rings and radial gaps are ubiquitous in protoplanetary disks, yet their
possible connection to planet formation is currently subject to intense
debates. In principle, giant planet formation leads to wide gaps which separate
the gas and dust mass reservoir in the outer disk, while lower mass planets
lead to shallow gaps which are manifested mainly on the dust component. We used
the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the star
HD169142, host to a prominent disk with deep wide gaps that sever the disk into
inner and outer regions. The new ALMA high resolution images allow for the
outer ring to be resolved as three narrow rings. The HD169142 disk thus hosts
both the wide gaps trait of transition disks and a narrow ring system similar
to those observed in the TW Hya and HL Tau systems. The mass reservoir beyond a
deep gap can thus host ring systems. The observed rings are narrow in radial
extent (width/radius of 1.5/57.3, 1.8/64.2 and 3.4/76.0, in au) and have
asymmetric mutual separations: the first and middle ring are separated by 7 au
while the middle and outermost ring are distanced by ~12 au. Using
hydrodynamical modeling we found that a simple explanation, involving a single
migrating low mass planet (10 M$_oplus$), entirely accounts for such an
apparently complex phenomenon. Inward migration of the planet naturally
explains the ring’s asymmetric mutual separation. The isolation of HD169142’s
outer rings thus allows a proof of concept to interpret the detailed
architecture of the outer region of protoplanetary disks with low mass planet
formation of mini-Neptune’s size, i.e. as in the protosolar nebula.
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