There is an intriguing and growing population of Neptune-sized planets with stellar obliquities near $sim90^{circ}$. One previously proposed formation pathway is a disk-driven resonance, which can take place at the end stages of planet formation in a system containing an inner Neptune, outer cold Jupiter, and protoplanetary disk. This mechanism occurs within the first $sim10$ Myr, but most of the polar Neptunes we see today are $sim$Gyrs old. Up until now, there has not been an extensive analysis of whether the polar orbits are stable over $sim$Gyr timescales. Tidal realignment mechanisms are known to operate in other systems, and if they are active here, this would cause theoretical tension with a primordial misalignment story. In this paper, we explore the effects of tidal evolution on the disk-driven resonance theory. We use both $N$-body and secular simulations to study tidal effects on both the initial resonant encounter and long-term evolution. We find that the polar orbits are remarkably stable on $sim$Gyr timescales. Inclination damping does not occur for the polar cases, although we do identify sub-polar cases where it is important. We consider two case study polar Neptunes, WASP-107 b and HAT-P-11 b, and study them in the context of this theory, finding consistency with present-day properties if their tidal quality factors are $Q gtrsim 10^4$ and $Q gtrsim 10^5$, respectively.
{"title":"Polar Neptunes are Stable to Tides","authors":"Emma Louden, Sarah Millholland","doi":"arxiv-2409.03679","DOIUrl":"https://doi.org/arxiv-2409.03679","url":null,"abstract":"There is an intriguing and growing population of Neptune-sized planets with\u0000stellar obliquities near $sim90^{circ}$. One previously proposed formation\u0000pathway is a disk-driven resonance, which can take place at the end stages of\u0000planet formation in a system containing an inner Neptune, outer cold Jupiter,\u0000and protoplanetary disk. This mechanism occurs within the first $sim10$ Myr,\u0000but most of the polar Neptunes we see today are $sim$Gyrs old. Up until now,\u0000there has not been an extensive analysis of whether the polar orbits are stable\u0000over $sim$Gyr timescales. Tidal realignment mechanisms are known to operate in\u0000other systems, and if they are active here, this would cause theoretical\u0000tension with a primordial misalignment story. In this paper, we explore the\u0000effects of tidal evolution on the disk-driven resonance theory. We use both\u0000$N$-body and secular simulations to study tidal effects on both the initial\u0000resonant encounter and long-term evolution. We find that the polar orbits are\u0000remarkably stable on $sim$Gyr timescales. Inclination damping does not occur\u0000for the polar cases, although we do identify sub-polar cases where it is\u0000important. We consider two case study polar Neptunes, WASP-107 b and HAT-P-11\u0000b, and study them in the context of this theory, finding consistency with\u0000present-day properties if their tidal quality factors are $Q gtrsim 10^4$ and\u0000$Q gtrsim 10^5$, respectively.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carlos E. Muñoz-Romero, Andrea Banzatti, Karin I. Öberg, Klaus M. Pontoppidan, Colette Salyk, Joan Najita, Geoffrey A. Blake, Sebastiaan Krijt, Nicole Arulanantham, Paola Pinilla, Feng Long, Giovanni Rosotti, Sean M. Andrews, David J. Wilner, Jenny Calahan, The JDISCS Collaboration
The mid-infrared water vapor emission spectrum provides a novel way to characterize the delivery of icy pebbles towards the innermost ($<5$ au) regions of planet-forming disks. Recently, JWST MIRI-MRS showed that compact disks exhibit an excess of low-energy water vapor emission relative to extended multi-gapped disks, suggesting that icy pebble drift is more efficient in the former. We carry out detailed emission line modeling to retrieve the excitation conditions of rotational water vapor emission in a sample of four compact and three extended disks within the JDISC Survey. We present two-temperature H$_2$O slab model retrievals and, for the first time, constrain the spatial distribution of water vapor by fitting parametric radial temperature and column density profiles. Such models statistically outperform the two-temperature slab fits. We find a correlation between the observable hot water vapor mass and stellar mass accretion rate, as well as an anti-correlation between cold water vapor mass and sub-mm dust disk radius, confirming previously reported water line flux trends. We find that the mid-IR spectrum traces H$_2$O with temperatures down to 180-300 K, but the coldest 150-170 K gas remains undetected. Furthermore the H$_2$O temperature profiles are generally steeper and cooler than the expected `super-heated' dust temperature in passive irradiated disks. The column density profiles are used to estimate icy pebble mass fluxes, which suggest that compact and extended disks may produce markedly distinct inner-disk exoplanet populations if local feeding mechanisms dominate their assembly.
中红外水蒸气发射光谱提供了一种新的方法来描述冰卵石向行星形成盘最内侧（小于5美元au）区域的输送情况。最近，JWST的MIRI-MRS显示，相对于扩展的多瓣盘，紧凑盘显示出过量的低能水蒸气发射，这表明冰卵石漂移在形成者中更有效率。我们对 JDISC 巡天中的四个紧凑盘和三个扩展盘样本进行了详细的发射线建模，以检索旋转水蒸气发射的激发条件。我们提出了两种温度的 H$_2$Oslab 模型检索，并首次通过拟合参数径向温度和柱密度剖面来约束水蒸气的空间分布。这种模型在统计上优于双温板拟合。我们发现可观测到的热水蒸气质量与恒星质量吸积率之间存在相关性，而冷水蒸气质量与亚微米尘埃盘半径之间存在反相关性，这证实了之前报道的水线通量趋势。我们发现，中红外光谱可以追踪到温度低至 180-300 K 的 H$_2$O，但最冷的 150-170 K 气体仍然没有被探测到。此外，H$_2$O 的温度曲线通常比被动辐射盘中预期的 "过热 "尘埃温度更陡峭和更低。柱密度剖面被用来估算冰卵石质量通量，这表明，如果本地供养机制在其组装中占主导地位，那么紧凑和扩展盘可能会产生明显不同的内盘系外行星群。
{"title":"Retrieval of Thermally-Resolved Water Vapor Distributions in Disks Observed with JWST-MIRI","authors":"Carlos E. Muñoz-Romero, Andrea Banzatti, Karin I. Öberg, Klaus M. Pontoppidan, Colette Salyk, Joan Najita, Geoffrey A. Blake, Sebastiaan Krijt, Nicole Arulanantham, Paola Pinilla, Feng Long, Giovanni Rosotti, Sean M. Andrews, David J. Wilner, Jenny Calahan, The JDISCS Collaboration","doi":"arxiv-2409.03831","DOIUrl":"https://doi.org/arxiv-2409.03831","url":null,"abstract":"The mid-infrared water vapor emission spectrum provides a novel way to\u0000characterize the delivery of icy pebbles towards the innermost ($<5$ au)\u0000regions of planet-forming disks. Recently, JWST MIRI-MRS showed that compact\u0000disks exhibit an excess of low-energy water vapor emission relative to extended\u0000multi-gapped disks, suggesting that icy pebble drift is more efficient in the\u0000former. We carry out detailed emission line modeling to retrieve the excitation\u0000conditions of rotational water vapor emission in a sample of four compact and\u0000three extended disks within the JDISC Survey. We present two-temperature H$_2$O\u0000slab model retrievals and, for the first time, constrain the spatial\u0000distribution of water vapor by fitting parametric radial temperature and column\u0000density profiles. Such models statistically outperform the two-temperature slab\u0000fits. We find a correlation between the observable hot water vapor mass and\u0000stellar mass accretion rate, as well as an anti-correlation between cold water\u0000vapor mass and sub-mm dust disk radius, confirming previously reported water\u0000line flux trends. We find that the mid-IR spectrum traces H$_2$O with\u0000temperatures down to 180-300 K, but the coldest 150-170 K gas remains\u0000undetected. Furthermore the H$_2$O temperature profiles are generally steeper\u0000and cooler than the expected `super-heated' dust temperature in passive\u0000irradiated disks. The column density profiles are used to estimate icy pebble\u0000mass fluxes, which suggest that compact and extended disks may produce markedly\u0000distinct inner-disk exoplanet populations if local feeding mechanisms dominate\u0000their assembly.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vaporized metal, silicates, and ices on the verge of re-condensing into solid or liquid particles appear in many contexts: behind shocks, in impact ejecta, and within the atmospheres and outflows of stars, disks, planets, and minor bodies. We speculate that a condensing gas might fragment, forming overdensities within relative voids, from a radiation-condensation instability. Seeded with small thermal fluctuations, a condensible gas will exhibit spatial variations in the density of particle condensates. Regions of higher particle density may radiate more, cooling faster. Faster cooling leads to still more condensation, lowering the local pressure. Regions undergoing runaway condensation may collapse under the pressure of their less condensed surroundings. Particle condensates will compactify with collapsing regions, into overdense clumps or macroscopic solids (planetesimals). As a first step toward realizing this hypothetical instability, we calculate the evolution of a small volume of condensing silicate vapor -- a spherical test "bubble" embedded in a background medium whose pressure and radiation field are assumed fixed for simplicity. Such a bubble condenses and collapses upon radiating its latent heat to the background, assuming its energy loss is not stopped by background irradiation. Collapse speeds can range up to sonic, similar to cavitation in terrestrial settings. Adding a non-condensible gas like hydrogen to the bubble stalls the collapse. We discuss whether cavitation can provide a way for mm-sized chondrules and refractory solids to assemble into meteorite parent bodies, focusing on CB/CH chondrites whose constituents likely condensed from silicate/metal vapor released from the most energetic asteroid collisions.
{"title":"Cavitating bubbles in condensing gas as a means of forming clumps, chondrites, and planetesimals","authors":"Eugene Chiang","doi":"arxiv-2409.02978","DOIUrl":"https://doi.org/arxiv-2409.02978","url":null,"abstract":"Vaporized metal, silicates, and ices on the verge of re-condensing into solid\u0000or liquid particles appear in many contexts: behind shocks, in impact ejecta,\u0000and within the atmospheres and outflows of stars, disks, planets, and minor\u0000bodies. We speculate that a condensing gas might fragment, forming\u0000overdensities within relative voids, from a radiation-condensation instability.\u0000Seeded with small thermal fluctuations, a condensible gas will exhibit spatial\u0000variations in the density of particle condensates. Regions of higher particle\u0000density may radiate more, cooling faster. Faster cooling leads to still more\u0000condensation, lowering the local pressure. Regions undergoing runaway\u0000condensation may collapse under the pressure of their less condensed\u0000surroundings. Particle condensates will compactify with collapsing regions,\u0000into overdense clumps or macroscopic solids (planetesimals). As a first step\u0000toward realizing this hypothetical instability, we calculate the evolution of a\u0000small volume of condensing silicate vapor -- a spherical test \"bubble\" embedded\u0000in a background medium whose pressure and radiation field are assumed fixed for\u0000simplicity. Such a bubble condenses and collapses upon radiating its latent\u0000heat to the background, assuming its energy loss is not stopped by background\u0000irradiation. Collapse speeds can range up to sonic, similar to cavitation in\u0000terrestrial settings. Adding a non-condensible gas like hydrogen to the bubble\u0000stalls the collapse. We discuss whether cavitation can provide a way for\u0000mm-sized chondrules and refractory solids to assemble into meteorite parent\u0000bodies, focusing on CB/CH chondrites whose constituents likely condensed from\u0000silicate/metal vapor released from the most energetic asteroid collisions.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joseph L. Hora, David E. Trilling, Andy J. Lopez-Oquendo, Howard A. Smith, Michael Mommert, Nicholas Moskovitz, Chris Foster, Michael S. Connelley, Charles Lockhart, John T. Rayner, Schelte J. Bus, Darryl Watanabe, Lars Bergknut, Morgan Bonnet, Alan Tokunaga
We describe the new design and current performance of the Mid-InfraRed Spectrometer and Imager (MIRSI) on the NASA Infrared Telescope Facility (IRTF). The system has been converted from a liquid nitrogen/liquid helium cryogen system to one that uses a closed-cycle cooler, which allows it to be kept on the telescope at operating temperature and available for observing on short notice, requiring less effort by the telescope operators and day crew to maintain operating temperature. Several other enhancements have been completed, including new detector readout electronics, an IRTF-style standard instrument user interface, new stepper motor driver electronics, and an optical camera that views the same field as the mid-IR instrument using a cold dichroic mirror, allowing for guiding and/or simultaneous optical imaging. The instrument performance is presented, both with an engineering-grade array used from 2021-2023, and a science-grade array installed in the fall of 2023. Some sample astronomical results are also shown. The upgraded MIRSI is a facility instrument at the IRTF available to all users.
{"title":"Design and Performance of the Upgraded Mid-InfraRed Spectrometer and Imager (MIRSI) on the NASA Infrared Telescope Facility","authors":"Joseph L. Hora, David E. Trilling, Andy J. Lopez-Oquendo, Howard A. Smith, Michael Mommert, Nicholas Moskovitz, Chris Foster, Michael S. Connelley, Charles Lockhart, John T. Rayner, Schelte J. Bus, Darryl Watanabe, Lars Bergknut, Morgan Bonnet, Alan Tokunaga","doi":"arxiv-2409.02752","DOIUrl":"https://doi.org/arxiv-2409.02752","url":null,"abstract":"We describe the new design and current performance of the Mid-InfraRed\u0000Spectrometer and Imager (MIRSI) on the NASA Infrared Telescope Facility (IRTF).\u0000The system has been converted from a liquid nitrogen/liquid helium cryogen\u0000system to one that uses a closed-cycle cooler, which allows it to be kept on\u0000the telescope at operating temperature and available for observing on short\u0000notice, requiring less effort by the telescope operators and day crew to\u0000maintain operating temperature. Several other enhancements have been completed,\u0000including new detector readout electronics, an IRTF-style standard instrument\u0000user interface, new stepper motor driver electronics, and an optical camera\u0000that views the same field as the mid-IR instrument using a cold dichroic\u0000mirror, allowing for guiding and/or simultaneous optical imaging. The\u0000instrument performance is presented, both with an engineering-grade array used\u0000from 2021-2023, and a science-grade array installed in the fall of 2023. Some\u0000sample astronomical results are also shown. The upgraded MIRSI is a facility\u0000instrument at the IRTF available to all users.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sota Arakawa, Daiki Yamamoto, Lily Ishizaki, Tamami Okamoto, Noriyuki Kawasaki
Meteorites and their components exhibit a diverse range of oxygen isotope compositions, and the isotopic exchange timescale between dust grains and ambient gas is a key parameter for understanding the spatiotemporal evolution of the solar nebula. As dust grains existed as macroscopic aggregates in the solar nebula, it is necessary to consider the isotopic exchange timescales for these aggregates. Here, we theoretically estimate the isotope exchange timescales between dust aggregates and ambient vapor. The isotope exchange process between aggregates and ambient vapor is divided into four processes: (i) supply of gas molecules to the aggregate surface, (ii) diffusion of molecules within the aggregate, (iii) isotope exchange on the surface of constituent particles, and (iv) isotope diffusion within the particles. We evaluate these timescales and assess which one becomes the rate-determining step. We reveal that the isotope exchange timescale is approximately the same as that of the constituent particles when the aggregate radius is smaller than the critical value, which is a few centimeters when considering the exchange reaction between amorphous forsterite aggregates and water vapor.
{"title":"Oxygen Isotope Exchange Between Dust Aggregates and Ambient Nebular Gas","authors":"Sota Arakawa, Daiki Yamamoto, Lily Ishizaki, Tamami Okamoto, Noriyuki Kawasaki","doi":"arxiv-2409.02736","DOIUrl":"https://doi.org/arxiv-2409.02736","url":null,"abstract":"Meteorites and their components exhibit a diverse range of oxygen isotope\u0000compositions, and the isotopic exchange timescale between dust grains and\u0000ambient gas is a key parameter for understanding the spatiotemporal evolution\u0000of the solar nebula. As dust grains existed as macroscopic aggregates in the\u0000solar nebula, it is necessary to consider the isotopic exchange timescales for\u0000these aggregates. Here, we theoretically estimate the isotope exchange\u0000timescales between dust aggregates and ambient vapor. The isotope exchange\u0000process between aggregates and ambient vapor is divided into four processes:\u0000(i) supply of gas molecules to the aggregate surface, (ii) diffusion of\u0000molecules within the aggregate, (iii) isotope exchange on the surface of\u0000constituent particles, and (iv) isotope diffusion within the particles. We\u0000evaluate these timescales and assess which one becomes the rate-determining\u0000step. We reveal that the isotope exchange timescale is approximately the same\u0000as that of the constituent particles when the aggregate radius is smaller than\u0000the critical value, which is a few centimeters when considering the exchange\u0000reaction between amorphous forsterite aggregates and water vapor.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julien Laurent-Varin, Théo James, Jean-Charles Marty, Laurent Jorda, Sebastien Le Maistre, Robert Gaskell
We provide a new gravity field of Comet 67P-C/G up to degree 4. We detect mass heterogeneity in the comet nucleus. The loss of mass is restimated at 0.28% of the comet's total mass (3 times larger than previous estimate). Comparison of the gravity field between pre- and post-perihelion allowed us to measure a shift in the comet's center of gravity of 35 m northward, attributed to ice sublimation process.
{"title":"New gravity field of comet 67P/C-G based on Rosetta's Doppler and optical data","authors":"Julien Laurent-Varin, Théo James, Jean-Charles Marty, Laurent Jorda, Sebastien Le Maistre, Robert Gaskell","doi":"arxiv-2409.02692","DOIUrl":"https://doi.org/arxiv-2409.02692","url":null,"abstract":"We provide a new gravity field of Comet 67P-C/G up to degree 4. We detect\u0000mass heterogeneity in the comet nucleus. The loss of mass is restimated at\u00000.28% of the comet's total mass (3 times larger than previous estimate).\u0000Comparison of the gravity field between pre- and post-perihelion allowed us to\u0000measure a shift in the comet's center of gravity of 35 m northward, attributed\u0000to ice sublimation process.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The key difficulty faced by 2D models for planet-disc interaction is in appropriately accounting for the impact of the disc's vertical structure on the dynamics. 3D effects are often mimicked via softening of the planet's potential; however, the planet-induced flow and torques often depend strongly on the choice of softening length. We show that for a linear adiabatic flow perturbing a vertically isothermal disc, there is a particular vertical average of the 3D equations of motion which exactly reproduces 2D fluid equations for arbitrary adiabatic index. There is a strong connection here with the Lubow-Pringle 2D mode of the disc. Correspondingly, we find a simple, general prescription for the consistent treatment of planetary potentials embedded within '2D' discs. The flow induced by a low-mass planet involves large-scale excited spiral density waves which transport angular momentum radially away from the planet, and 'horseshoe streamlines' within the co-orbital region. We derive simple linear equations governing the flow which locally capture both effects faithfully simultaneously. We present an accurate co-orbital flow solution allowing for inexpensive future study of corotation torques, and predict the vertical structure of the co-orbital flow and horseshoe region width for different values of adiabatic index, as well as the vertical dependence of the initial shock location. We find strong agreement with the flow computed in 3D numerical simulations, and with 3D one-sided Lindblad torque estimates, which are a factor of 2 to 3 times lower than values from previous 2D simulations.
{"title":"Horseshoes and spiral waves: capturing the 3D flow induced by a low-mass planet analytically","authors":"Joshua J. Brown, Gordon I. Ogilvie","doi":"arxiv-2409.02687","DOIUrl":"https://doi.org/arxiv-2409.02687","url":null,"abstract":"The key difficulty faced by 2D models for planet-disc interaction is in\u0000appropriately accounting for the impact of the disc's vertical structure on the\u0000dynamics. 3D effects are often mimicked via softening of the planet's\u0000potential; however, the planet-induced flow and torques often depend strongly\u0000on the choice of softening length. We show that for a linear adiabatic flow\u0000perturbing a vertically isothermal disc, there is a particular vertical average\u0000of the 3D equations of motion which exactly reproduces 2D fluid equations for\u0000arbitrary adiabatic index. There is a strong connection here with the\u0000Lubow-Pringle 2D mode of the disc. Correspondingly, we find a simple, general\u0000prescription for the consistent treatment of planetary potentials embedded\u0000within '2D' discs. The flow induced by a low-mass planet involves large-scale\u0000excited spiral density waves which transport angular momentum radially away\u0000from the planet, and 'horseshoe streamlines' within the co-orbital region. We\u0000derive simple linear equations governing the flow which locally capture both\u0000effects faithfully simultaneously. We present an accurate co-orbital flow\u0000solution allowing for inexpensive future study of corotation torques, and\u0000predict the vertical structure of the co-orbital flow and horseshoe region\u0000width for different values of adiabatic index, as well as the vertical\u0000dependence of the initial shock location. We find strong agreement with the\u0000flow computed in 3D numerical simulations, and with 3D one-sided Lindblad\u0000torque estimates, which are a factor of 2 to 3 times lower than values from\u0000previous 2D simulations.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thomas Meier, Christian Reinhardt, Miles Timpe, Joachim Stadel, Ben Moore
In the leading theory of lunar formation, known as the giant impact hypothesis, a collision between two planet-size objects resulted in a young Earth surrounded by a circumplanetary debris disk from which the Moon later accreted. The range of giant impacts that could conceivably explain the Earth-Moon system is limited by the set of known physical and geochemical constraints. However, while several distinct Moon-forming impact scenarios have been proposed -- from small, high-velocity impactors to low-velocity mergers between equal-mass objects -- none of these scenarios have been successful at explaining the full set of known constraints, especially without invoking one or more controversial post-impact processes. Allowing for pre-impact rotation of the colliding bodies has been suggested as an avenue which may produce more promising collision outcomes. However, to date, only limited studies of pre-impact rotation have been conducted. Therefore, in the second paper of this series, we focus on pairwise impacts between rotating bodies. Using non-rotating collisions as a baseline, we systematically study the effects of rotation on collision outcomes. We consider nine distinct rotation configurations and a range of rotation rates up to the rotational stability limit. Notably, we identify a population of collisions that can produce low post-impact angular momentum budgets and massive, iron-poor protolunar disks.
{"title":"A Systematic Survey of Moon-Forming Giant Impacts. II. Rotating bodies","authors":"Thomas Meier, Christian Reinhardt, Miles Timpe, Joachim Stadel, Ben Moore","doi":"arxiv-2409.02746","DOIUrl":"https://doi.org/arxiv-2409.02746","url":null,"abstract":"In the leading theory of lunar formation, known as the giant impact\u0000hypothesis, a collision between two planet-size objects resulted in a young\u0000Earth surrounded by a circumplanetary debris disk from which the Moon later\u0000accreted. The range of giant impacts that could conceivably explain the\u0000Earth-Moon system is limited by the set of known physical and geochemical\u0000constraints. However, while several distinct Moon-forming impact scenarios have\u0000been proposed -- from small, high-velocity impactors to low-velocity mergers\u0000between equal-mass objects -- none of these scenarios have been successful at\u0000explaining the full set of known constraints, especially without invoking one\u0000or more controversial post-impact processes. Allowing for pre-impact rotation\u0000of the colliding bodies has been suggested as an avenue which may produce more\u0000promising collision outcomes. However, to date, only limited studies of\u0000pre-impact rotation have been conducted. Therefore, in the second paper of this\u0000series, we focus on pairwise impacts between rotating bodies. Using\u0000non-rotating collisions as a baseline, we systematically study the effects of\u0000rotation on collision outcomes. We consider nine distinct rotation\u0000configurations and a range of rotation rates up to the rotational stability\u0000limit. Notably, we identify a population of collisions that can produce low\u0000post-impact angular momentum budgets and massive, iron-poor protolunar disks.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aurora Y. Kesseli, Hayley Beltz, Emily Rauscher, I. A. G. Snellen
Due to the unprecedented signal strengths offered by the newest high-resolution spectrographs on 10-m class telescopes, exploring the 3D nature of exoplanets is possible with an unprecedented level of precision. In this paper, we present a new technique to probe the vertical structure of exoplanetary winds and dynamics using ensembles of planet absorption lines of varying opacity, and apply it to the well-studied ultra-hot Jupiter WASP-76b. We then compare these results to state-of-the-art global circulation models (GCMs) with varying magnetic drag prescriptions. We find that the known asymmetric velocity shift in Fe I absorption during transit persists at all altitudes, and observe tentative trends for stronger blueshifts and more narrow line profiles deeper in the atmosphere. By comparing three different model prescriptions (a hydrodynamical model with no drag, a magnetic drag model, and a uniform drag model) we are able to rule out the uniform drag model due to inconsistencies with observed trends in the data. We find that the magnetic model is slightly favored over the the hydrodynamic model, and note that this 3-Gauss kinematic magnetohydrodynamical GCM is also favored when compared to low-resolution data. Future generation high-resolution spectrographs on Extremely large telescopes (ELTs) will greatly increase signals and make methods like these possible with higher precision and for a wider range of objects.
{"title":"Up, Up, and Away: Winds and Dynamical Structure as a Function of Altitude in the Ultra-Hot Jupiter WASP-76b","authors":"Aurora Y. Kesseli, Hayley Beltz, Emily Rauscher, I. A. G. Snellen","doi":"arxiv-2409.03124","DOIUrl":"https://doi.org/arxiv-2409.03124","url":null,"abstract":"Due to the unprecedented signal strengths offered by the newest\u0000high-resolution spectrographs on 10-m class telescopes, exploring the 3D nature\u0000of exoplanets is possible with an unprecedented level of precision. In this\u0000paper, we present a new technique to probe the vertical structure of\u0000exoplanetary winds and dynamics using ensembles of planet absorption lines of\u0000varying opacity, and apply it to the well-studied ultra-hot Jupiter WASP-76b.\u0000We then compare these results to state-of-the-art global circulation models\u0000(GCMs) with varying magnetic drag prescriptions. We find that the known\u0000asymmetric velocity shift in Fe I absorption during transit persists at all\u0000altitudes, and observe tentative trends for stronger blueshifts and more narrow\u0000line profiles deeper in the atmosphere. By comparing three different model\u0000prescriptions (a hydrodynamical model with no drag, a magnetic drag model, and\u0000a uniform drag model) we are able to rule out the uniform drag model due to\u0000inconsistencies with observed trends in the data. We find that the magnetic\u0000model is slightly favored over the the hydrodynamic model, and note that this\u00003-Gauss kinematic magnetohydrodynamical GCM is also favored when compared to\u0000low-resolution data. Future generation high-resolution spectrographs on\u0000Extremely large telescopes (ELTs) will greatly increase signals and make\u0000methods like these possible with higher precision and for a wider range of\u0000objects.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jessica Speedie, Ruobing Dong, Cassandra Hall, Cristiano Longarini, Benedetta Veronesi, Teresa Paneque-Carreño, Giuseppe Lodato, Ya-Wen Tang, Richard Teague, Jun Hashimoto
The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms induced by gravitational instability -- if the disk is gravitationally unstable. For this to be possible, the disk must be massive compared to the central star: a disk-to-star mass ratio of 1/10 is widely held as the rough threshold for triggering gravitational instability, inciting significant non-Keplerian dynamics and generating prominent spiral arms. While estimating disk masses has historically been challenging, the motion of the gas can reveal the presence of gravitational instability through its effect on the disk velocity structure. Here we present kinematic evidence of gravitational instability in the disk around AB Aurigae, using deep observations of 13CO and C18O line emission with the Atacama Large Millimeter/submillimeter Array (ALMA). The observed kinematic signals strongly resemble predictions from simulations and analytic modelling. From quantitative comparisons, we infer a disk mass of up to 1/3 the stellar mass enclosed within 1" to 5" on the sky.
{"title":"Gravitational instability in a planet-forming disk","authors":"Jessica Speedie, Ruobing Dong, Cassandra Hall, Cristiano Longarini, Benedetta Veronesi, Teresa Paneque-Carreño, Giuseppe Lodato, Ya-Wen Tang, Richard Teague, Jun Hashimoto","doi":"arxiv-2409.02196","DOIUrl":"https://doi.org/arxiv-2409.02196","url":null,"abstract":"The canonical theory for planet formation in circumstellar disks proposes\u0000that planets are grown from initially much smaller seeds. The long-considered\u0000alternative theory proposes that giant protoplanets can be formed directly from\u0000collapsing fragments of vast spiral arms induced by gravitational instability\u0000-- if the disk is gravitationally unstable. For this to be possible, the disk\u0000must be massive compared to the central star: a disk-to-star mass ratio of 1/10\u0000is widely held as the rough threshold for triggering gravitational instability,\u0000inciting significant non-Keplerian dynamics and generating prominent spiral\u0000arms. While estimating disk masses has historically been challenging, the\u0000motion of the gas can reveal the presence of gravitational instability through\u0000its effect on the disk velocity structure. Here we present kinematic evidence\u0000of gravitational instability in the disk around AB Aurigae, using deep\u0000observations of 13CO and C18O line emission with the Atacama Large\u0000Millimeter/submillimeter Array (ALMA). The observed kinematic signals strongly\u0000resemble predictions from simulations and analytic modelling. From quantitative\u0000comparisons, we infer a disk mass of up to 1/3 the stellar mass enclosed within\u00001\" to 5\" on the sky.","PeriodicalId":501209,"journal":{"name":"arXiv - PHYS - Earth and Planetary Astrophysics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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