SO and SiS Emission Tracing an Embedded Planet and Compact $^{12}$CO and $^{13}$CO Counterparts in the HD 169142 Disk. (arXiv:2306.13710v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Law_C/0/1/0/all/0/1">Charles J. Law</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Booth_A/0/1/0/all/0/1">Alice S. Booth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oberg_K/0/1/0/all/0/1">Karin I. Öberg</a>
Planets form in dusty, gas-rich disks around young stars, while at the same
time, the planet formation process alters the physical and chemical structure
of the disk itself. Embedded planets will locally heat the disk and sublimate
volatile-rich ices, or in extreme cases, result in shocks that sputter heavy
atoms such as Si from dust grains. This should cause chemical asymmetries
detectable in molecular gas observations. Using high-angular-resolution ALMA
archival data of the HD 169142 disk, we identify compact SO J=8$_8$-7$_7$ and
SiS J=19-18 emission coincident with the position of a ${sim}$2 M$_{rm{Jup}}$
planet seen as a localized, Keplerian NIR feature within a gas-depleted,
annular dust gap at ${approx}$38 au. The SiS emission is located along an
azimuthal arc and has a similar morphology as a known $^{12}$CO kinematic
excess. This is the first tentative detection of SiS emission in a
protoplanetary disk and suggests that the planet is driving sufficiently strong
shocks to produce gas-phase SiS. We also report the discovery of compact
$^{12}$CO and $^{13}$CO J=3-2 emission coincident with the planet location.
Taken together, a planet-driven outflow provides the best explanation for the
properties of the observed chemical asymmetries. We also resolve a bright,
azimuthally-asymmetric SO ring at ${approx}$24 au. While most of this SO
emission originates from ice sublimation, its asymmetric distribution implies
azimuthal temperature variations driven by a misaligned inner disk or
planet-disk interactions. Overall, the HD 169142 disk shows several distinct
chemical signatures related to giant planet formation and presents a powerful
template for future searches of planet-related chemical asymmetries in
protoplanetary disks.
Planets form in dusty, gas-rich disks around young stars, while at the same
time, the planet formation process alters the physical and chemical structure
of the disk itself. Embedded planets will locally heat the disk and sublimate
volatile-rich ices, or in extreme cases, result in shocks that sputter heavy
atoms such as Si from dust grains. This should cause chemical asymmetries
detectable in molecular gas observations. Using high-angular-resolution ALMA
archival data of the HD 169142 disk, we identify compact SO J=8$_8$-7$_7$ and
SiS J=19-18 emission coincident with the position of a ${sim}$2 M$_{rm{Jup}}$
planet seen as a localized, Keplerian NIR feature within a gas-depleted,
annular dust gap at ${approx}$38 au. The SiS emission is located along an
azimuthal arc and has a similar morphology as a known $^{12}$CO kinematic
excess. This is the first tentative detection of SiS emission in a
protoplanetary disk and suggests that the planet is driving sufficiently strong
shocks to produce gas-phase SiS. We also report the discovery of compact
$^{12}$CO and $^{13}$CO J=3-2 emission coincident with the planet location.
Taken together, a planet-driven outflow provides the best explanation for the
properties of the observed chemical asymmetries. We also resolve a bright,
azimuthally-asymmetric SO ring at ${approx}$24 au. While most of this SO
emission originates from ice sublimation, its asymmetric distribution implies
azimuthal temperature variations driven by a misaligned inner disk or
planet-disk interactions. Overall, the HD 169142 disk shows several distinct
chemical signatures related to giant planet formation and presents a powerful
template for future searches of planet-related chemical asymmetries in
protoplanetary disks.
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