Asteroids formed in a dynamically quiescent disk but their orbits became gravitationally stirred ... more Asteroids formed in a dynamically quiescent disk but their orbits became gravitationally stirred enough by Jupiter to lead to high-speed collisions. As a result, many dozen large asteroids have been disrupted by impacts over the age of the Solar System, producing groups of fragments known as asteroid families. Here we explain how the asteroid families are identified, review their current inventory, and discuss how they can be used to get insights into long-term dynamics of main belt asteroids. Electronic tables of the membership for 122 notable families are reported on the Planetary Data System node. See related chapters in this volume for the significance of asteroid families for studies of physics of large scale collisions, collisional history of the main belt, source regions of the near-Earth asteroids, meteorites and dust particles, and space weathering.
We develop an analytic model for transit timing variations produced by orbital conjunctions betwe... more We develop an analytic model for transit timing variations produced by orbital conjunctions between gravitationally interacting planets. If the planetary orbits have tight orbital spacing, which is a common case among the Kepler planets, the effect of a single conjunction can be best described as: (1) a step-like change of the transit timing ephemeris with subsequent transits of the inner planet being delayed and those of the outer planet being sped up, and (2) a discrete change in sampling of the underlying oscillations from eccentricity-related interaction terms. In the limit of small orbital eccentricities, our analytic model gives explicit equations for these effects as a function of the mass and orbital separation of planets. We point out that a detection of the conjunction effect in real data is of crucial importance for the physical characterization of planetary systems from transit timing variations.
While not detected yet, pairs of exoplanets in the 1:1 mean motion resonance probably exist. Low ... more While not detected yet, pairs of exoplanets in the 1:1 mean motion resonance probably exist. Low eccentricity, near-planar orbits, which in the comoving frame follow the horseshoe trajectories, are one of the possible stable configurations. Here we study transit timing variations produced by mutual gravitational interaction of planets in this orbital architecture, with the goal to develop methods that can be used to recognize this case in observational data. In particular, we use a semi-analytic model to derive parametric constraints that should facilitate data analysis. We show that characteristic traits of the transit timing variations can directly constrain the (i) ratio of planetary masses, and (ii) their total mass (divided by that of the central star) as a function of the minimum angular separation as seen from the star. In an ideal case, when transits of both planets are observed and well characterized, the minimum angular separation can also be inferred from the data. As a result, parameters derived from the observed transit timing series alone can directly provide both planetary masses scaled to the central star mass.
The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 an... more The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, low eccentricities and inclinations of 16-35 degrees. Small asteroids in the Hungaria region are dominated by a collisional family associated with (434) Hungaria. The dominant spectral type of the Hungaria group is the E or X-type , mostly due to the E-type composition of Hungaria and its genetic family. It is widely believed the E-type asteroids are related to the aubrite meteorites, also known as enstatite achondrites . Here we explore the hypothesis that aubrites originate in the Hungaria family. In order to test this connection, we compare model Cosmic Ray Exposure ages from orbital integrations of model meteoroids with those of aubrites. We show that long CRE ages of aubrites (longest among stony meteorite groups) reflect the delivery route of meteoroids from Hungarias to Earth being different than those from main-belt asteroids. We find that the meteoroids from Hungarias predominantly reach Earth by Yarkovsky-drifting across the orbit of Mars, with no assistance from orbital resonances. We conclude that the CRE ages of aubrites are fully consistent with a dominant source at the inner boundary of the Hungaria family at 1.7 AU. From here, meteoroids reach Earth through the Mars-crossing region, with relatively quick delivery times favored due to collisions (with Hungarias and the inner main-belt objects). We find that, after Vesta, (434) Hungaria is the best candidate for an asteroidal source of an achondrite group.
The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions be... more The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, 12-hour TTV amplitude. Here we report a thorough analysis of KOI-142.01's transits. We discover periodic Transit Duration Variations (TDVs) of KOI-142.01 that are nearly in phase with the observed TTVs. We show that KOI-142.01's TTVs and TDVs uniquely detect a non-transiting companion with a mass 0.7 that of Jupiter (KOI-142c). KOI-142.01's mass inferred from the transit variations is consistent with the measured transit depth, suggesting a Neptune class planet (KOI-142b). The orbital period ratio P_c/P_b=2.03 indicates that the two planets are just wide of the 2:1 resonance. The present dynamics of this system, characterized here in detail, can be used to test various formation theories that have been proposed to exp...
From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select sev... more From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select seven targets with favorable properties for the capacity to dynamically maintain an exomoon and present a detectable signal. These seven candidates were identified through our automatic target selection (TSA) algorithm and target selection prioritization (TSP) filtering, whereby we excluded systems exhibiting significant time-correlated noise and focussed on those with a single transiting planet candidate of radius less than 6 Earth radii. We find no compelling evidence for an exomoon around any of the seven KOIs but constrain the satellite-to-planet mass ratios for each. For four of the seven KOIs, we estimate a 95% upper quantile of M_S/M_P<0.04, which given the radii of the candidates, likely probes down to sub-Earth masses. We also derive precise transit times and durations for each candidate and find no evidence for dynamical variations in any of the KOIs. With just a few systems an...
Two decades ago, empirical evidence concerning the existence and frequency of planets around star... more Two decades ago, empirical evidence concerning the existence and frequency of planets around stars, other than our own, was absent. Since this time, the detection of extrasolar planets from Jupiter-sized to most recently Earth-sized worlds has blossomed and we are finally able to shed light on the plurality of Earth-like, habitable planets in the cosmos. Extrasolar moons may also be frequent habitable worlds but their detection or even systematic pursuit remains lacking in the current literature. Here, we present a description of the first systematic search for extrasolar moons as part of a new observational project called "The Hunt for Exomoons with Kepler" (HEK). The HEK project distills the entire list of known transiting planet candidates found by Kepler (2326 at the time of writing) down to the most promising candidates for hosting a moon. Selected targets are fitted using a multimodal nested sampling algorithm coupled with a planet-with-moon light curve modelling rou...
Previous works have identified families halos by an analysis in proper elements domains, or by us... more Previous works have identified families halos by an analysis in proper elements domains, or by using Sloan Digital Sky Survey-Moving Object Catalog data, fourth release (SDSS-MOC4) multi-band photometry to infer the asteroid taxonomy, or by a combination of the two methods. The limited number of asteroids for which geometric albedo was known until recently discouraged in the past the extensive use of this additional parameter, which is however of great importance in identifying an asteroid taxonomy. The new availability of geometric albedo data from the Wide-field Infrared Survey Explorer (WISE) mission for about 100,000 asteroids significantly increased the sample of objects for which such information, with some errors, is now known. In this work we proposed a new method to identify families halos in a multi-domain space composed by proper elements, SDSS-MOC4 (a*,i-z) colors, and WISE geometric albedo for the whole main belt (and the Hungaria and Cybele orbital regions). Assuming t...
V-type asteroids are bodies whose surfaces are constituted of basalt. In the Main Asteroid Belt, ... more V-type asteroids are bodies whose surfaces are constituted of basalt. In the Main Asteroid Belt, most of these asteroids are assumed to come from the basaltic crust of Asteroid (4) Vesta. This idea is mainly supported by (i) the fact that almost all the known V-type asteroids are in the same region of the belt as (4) Vesta, i.e., the inner belt (semi-major axis 2.1<a<2.5 AU), (ii) the existence of a dynamical asteroid family associated to (4) Vesta, and (iii) the observational evidence of at least one large craterization event on Vesta's surface. One V-type asteroid that is difficult to fit in this scenario is (1459) Magnya, located in the outer asteroid belt, i.e., too far away from (4) Vesta as to have a real possibility of coming from it. The recent discovery of the first V-type asteroid in the middle belt (2.5<a<2.8 AU), (21238) 1995WV7 [Binzel, R.P., Masi, G., Foglia, S., 2006. Bull. Am. Astron. Soc. 38, 627; Hammergren, M., Gyuk, G., Puckett, A., 2006. ArXiv e-...
Evidence in the Solar System suggests that the giant planets underwent an epoch of radial migrati... more Evidence in the Solar System suggests that the giant planets underwent an epoch of radial migration that was very rapid, with an e-folding timescale shorter than 1~Myr. It is probable that the cause of this migration was that the giant planets experienced an orbital instability that caused them to encounter each other, resulting in radial migration. Several works suggest that this dynamical instability occurred `late', long after all the planets had formed and the solar nebula had dissipated. Assuming that the terrestrial planets had already formed, then their orbits would have been affected by the migration of the giant planets. As a result, how did the orbits of the terrestrial planets change? And can we use this migration to obtain information on the primordial orbits of the terrestrial planets? We directly model a large number of terrestrial planet systems and their response to giant planet migration. We study the change in the Angular Momentum Deficit (AMD) of the terrstria...
KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 an... more KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 and KOI-884, the observed Transit Timing Variations (TTVs) of the inner transiting planet are used to detect an outer non-transiting planet. The outer planet in KOI-884 is 2.6 Jupiter masses and has the orbital period just narrow of the 3:1 resonance with the inner planet (orbital period ratio 2.93). The distribution of parameters inferred from KOI-319.01's TTVs is bimodal with either a 1.6 Neptune-mass (M_N) planet wide of the 5:3 resonance (period 80.1 d) or a 1 Saturn-mass planet wide of the 7:3 resonance (period 109.2 d). The radial velocity measurements can be used in this case to determine which of these parameter modes is correct. KOI-227.01's TTVs with large 10 hour amplitude can be obtained for planetary-mass companions in various major resonances. Based on the Bayesian evidence, the current TTV data favor the outer 2:1 resonance with a companion mass 1.5 M_N, but this sol...
Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bendin... more Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bending from the equator to the orbital plane of Saturn. The orbital inclination of Iapetus to the local Laplace plane is ~8 deg, which is unexpected, because the inclination should be ~0 if Iapetus formed from a circumplanetary disk on the Laplace surface. It thus appears that some process has pumped up Iapetus's inclination while leaving its eccentricity near zero (e=0.03 at present). Here we examined the possibility that Iapetus's inclination was excited during the early solar system instability when encounters between Saturn and ice giants occurred. We found that the dynamical effects of planetary encounters on Iapetus's orbit sensitively depend on the distance of the few closest encounters. In four out of ten instability cases studied here, the orbital perturbations were too large to be plausible. In one case, Iapetus's orbit was practically unneffected. In the remaining f...
The Nice model of the dynamical instability and migration of the giant planets can explain many p... more The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present Solar System, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites, and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorny & Morbidelli (2012) that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits we...
Proceedings of the International Astronomical Union, 2006
The effect of the space weathering on the spectral properties of the S-complex asteroids (both Ma... more The effect of the space weathering on the spectral properties of the S-complex asteroids (both Main Belt bodies and near-Earth asteroids) has been widely discussed in recent times. It has also shown that the evolution of spectral properties of planet-crossing bodies, and in particular of near-Earth asteroids (NEAs), is also affected by other physical processes, such as tidal resurfacing due to close encounters with planetary bodies. In this paper we show how to combine previous analyses with the purpose of obtaining a global model for NEAs space weathering.
Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bending fr... more Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bending from the equator to the orbital plane of Saturn. The orbital inclination of Iapetus to the local Laplace plane is ≃ 8 • , which is unexpected, because the inclination should be ≃ 0 if Iapetus formed from a circumplanetary disk on the Laplace surface. It thus appears that some process has pumped up Iapetus's inclination while leaving its eccentricity near zero (e ≃ 0.03 at present). Here we examined the possibility that Iapetus's inclination was excited during the early solar system instability when encounters between Saturn and ice giants occurred. We found that the dynamical effects of planetary encounters on Iapetus's orbit sensitively depend on the distance of the few closest encounters. In four out of ten instability cases studied here, the orbital perturbations were too large to be plausible. In one case, Iapetus's orbit was practically unneffected. In the remaining five cases, the perturbations of Iapetus's inclination were adequate to explain its present value. In three of these cases, however, Iapetus's eccentricity was excited to >0.1-0.25, and it is not clear whether it could have been damped to its present value (≃ 0.03) by some subsequent process (e.g., tides and dynamical friction from captured irregular satellites do not seem to be strong enough). Our results therefore imply that only 2 out of 10 instability cases (∼20%) can excite Iapetus's inclination to its present value (∼30% of trials lead to >5 • ) while leaving its orbital eccentricity low.
Proceedings of the International Astronomical Union, 2005
Non-gravitational perturbations, regardless being many orders of magnitude weaker than gravity, h... more Non-gravitational perturbations, regardless being many orders of magnitude weaker than gravity, hold keys to fully understand the evolution of small Solar System bodies. This is because individual bodies, or their entire groups, manifest traces of a long-term accumulated changes by these effects.
Proceedings of the International Astronomical Union, 2004
... Non-gravitational perturbations and evolution of the asteroid main belt ... Page 3. Non-gravi... more ... Non-gravitational perturbations and evolution of the asteroid main belt ... Page 3. Non-gravitational perturbations... 147 1969; O’Brien & Greenberg 2003). ...
KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 an... more KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 and KOI-884, the observed Transit Timing Variations (TTVs) of the inner transiting planet are used to detect an outer non-transiting planet. The outer planet in KOI-884 is ≃2.6 Jupiter masses and has the orbital period just narrow of the 3:1 resonance with the inner planet (orbital period ratio 2.93). The distribution of parameters inferred from KOI-319.01's TTVs is bimodal with either a ≃1.6 Neptune-mass (M N ) planet wide of the 5:3 resonance (period 80.1 d) or a ≃1 Saturn-mass planet wide of the 7:3 resonance (period 109.2 d). The radial velocity measurements can be used in this case to determine which of these parameter modes is correct. KOI-227.01's TTVs with large ≃10 hour amplitude can be obtained for planetary-mass companions in various major resonances. Based on the Bayesian evidence, the current TTV data favor the outer 2:1 resonance with a companion mass ≃1.5 M N , but this solution implies a very large density of KOI-227.01. The inner and outer 3:2 resonance solutions with sub-Neptune-mass companions are physically more plausible, but will need to be verified.
ABSTRACT Embedded in the gaseous protoplanetary disk, Jupiter and Saturn naturally become trapped... more ABSTRACT Embedded in the gaseous protoplanetary disk, Jupiter and Saturn naturally become trapped in 3:2 resonance and migrate outward. This serves as the basis of the Grand Tack model. However, previous hydrodynamical simulations were restricted to isothermal disks, with moderate aspect ratio and viscosity. Here we simulate the orbital evolution of the gas giants in disks with viscous heating and radiative cooling. We find that Jupiter and Saturn migrate outward in 3:2 resonance in modest-mass ($M_{disk} \approx M_{MMSN}$, where MMSN is the &quot;minimum-mass solar nebula&quot;) disks with viscous stress parameter $\alpha$ between $10^{-3}$ and $10^{-2} $. In disks with relatively low-mass ($M_{disk} \lesssim M_{MMSN}$) , Jupiter and Saturn get captured in 2:1 resonance and can even migrate outward in low-viscosity disks ($\alpha \le 10^{-4}$). Such disks have a very small aspect ratio ($h\sim 0.02-0.03$) that favors outward migration after capture in 2:1 resonance, as confirmed by isothermal runs which resulted in a similar outcome for $h \sim 0.02$ and $\alpha \le 10^{-4}$. We also performed N-body runs of the outer Solar System starting from the results of our hydrodynamical simulations and including 2-3 ice giants. After dispersal of the gaseous disk, a Nice model instability starting with Jupiter and Saturn in 2:1 resonance results in good Solar Systems analogs. We conclude that in a cold Solar Nebula, the 2:1 resonance between Jupiter and Saturn can lead to outward migration of the system, and this may represent an alternative scenario for the evolution of the Solar System.
Asteroids formed in a dynamically quiescent disk but their orbits became gravitationally stirred ... more Asteroids formed in a dynamically quiescent disk but their orbits became gravitationally stirred enough by Jupiter to lead to high-speed collisions. As a result, many dozen large asteroids have been disrupted by impacts over the age of the Solar System, producing groups of fragments known as asteroid families. Here we explain how the asteroid families are identified, review their current inventory, and discuss how they can be used to get insights into long-term dynamics of main belt asteroids. Electronic tables of the membership for 122 notable families are reported on the Planetary Data System node. See related chapters in this volume for the significance of asteroid families for studies of physics of large scale collisions, collisional history of the main belt, source regions of the near-Earth asteroids, meteorites and dust particles, and space weathering.
We develop an analytic model for transit timing variations produced by orbital conjunctions betwe... more We develop an analytic model for transit timing variations produced by orbital conjunctions between gravitationally interacting planets. If the planetary orbits have tight orbital spacing, which is a common case among the Kepler planets, the effect of a single conjunction can be best described as: (1) a step-like change of the transit timing ephemeris with subsequent transits of the inner planet being delayed and those of the outer planet being sped up, and (2) a discrete change in sampling of the underlying oscillations from eccentricity-related interaction terms. In the limit of small orbital eccentricities, our analytic model gives explicit equations for these effects as a function of the mass and orbital separation of planets. We point out that a detection of the conjunction effect in real data is of crucial importance for the physical characterization of planetary systems from transit timing variations.
While not detected yet, pairs of exoplanets in the 1:1 mean motion resonance probably exist. Low ... more While not detected yet, pairs of exoplanets in the 1:1 mean motion resonance probably exist. Low eccentricity, near-planar orbits, which in the comoving frame follow the horseshoe trajectories, are one of the possible stable configurations. Here we study transit timing variations produced by mutual gravitational interaction of planets in this orbital architecture, with the goal to develop methods that can be used to recognize this case in observational data. In particular, we use a semi-analytic model to derive parametric constraints that should facilitate data analysis. We show that characteristic traits of the transit timing variations can directly constrain the (i) ratio of planetary masses, and (ii) their total mass (divided by that of the central star) as a function of the minimum angular separation as seen from the star. In an ideal case, when transits of both planets are observed and well characterized, the minimum angular separation can also be inferred from the data. As a result, parameters derived from the observed transit timing series alone can directly provide both planetary masses scaled to the central star mass.
The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 an... more The Hungaria asteroids are interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, low eccentricities and inclinations of 16-35 degrees. Small asteroids in the Hungaria region are dominated by a collisional family associated with (434) Hungaria. The dominant spectral type of the Hungaria group is the E or X-type , mostly due to the E-type composition of Hungaria and its genetic family. It is widely believed the E-type asteroids are related to the aubrite meteorites, also known as enstatite achondrites . Here we explore the hypothesis that aubrites originate in the Hungaria family. In order to test this connection, we compare model Cosmic Ray Exposure ages from orbital integrations of model meteoroids with those of aubrites. We show that long CRE ages of aubrites (longest among stony meteorite groups) reflect the delivery route of meteoroids from Hungarias to Earth being different than those from main-belt asteroids. We find that the meteoroids from Hungarias predominantly reach Earth by Yarkovsky-drifting across the orbit of Mars, with no assistance from orbital resonances. We conclude that the CRE ages of aubrites are fully consistent with a dominant source at the inner boundary of the Hungaria family at 1.7 AU. From here, meteoroids reach Earth through the Mars-crossing region, with relatively quick delivery times favored due to collisions (with Hungarias and the inner main-belt objects). We find that, after Vesta, (434) Hungaria is the best candidate for an asteroidal source of an achondrite group.
The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions be... more The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, 12-hour TTV amplitude. Here we report a thorough analysis of KOI-142.01's transits. We discover periodic Transit Duration Variations (TDVs) of KOI-142.01 that are nearly in phase with the observed TTVs. We show that KOI-142.01's TTVs and TDVs uniquely detect a non-transiting companion with a mass 0.7 that of Jupiter (KOI-142c). KOI-142.01's mass inferred from the transit variations is consistent with the measured transit depth, suggesting a Neptune class planet (KOI-142b). The orbital period ratio P_c/P_b=2.03 indicates that the two planets are just wide of the 2:1 resonance. The present dynamics of this system, characterized here in detail, can be used to test various formation theories that have been proposed to exp...
From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select sev... more From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select seven targets with favorable properties for the capacity to dynamically maintain an exomoon and present a detectable signal. These seven candidates were identified through our automatic target selection (TSA) algorithm and target selection prioritization (TSP) filtering, whereby we excluded systems exhibiting significant time-correlated noise and focussed on those with a single transiting planet candidate of radius less than 6 Earth radii. We find no compelling evidence for an exomoon around any of the seven KOIs but constrain the satellite-to-planet mass ratios for each. For four of the seven KOIs, we estimate a 95% upper quantile of M_S/M_P<0.04, which given the radii of the candidates, likely probes down to sub-Earth masses. We also derive precise transit times and durations for each candidate and find no evidence for dynamical variations in any of the KOIs. With just a few systems an...
Two decades ago, empirical evidence concerning the existence and frequency of planets around star... more Two decades ago, empirical evidence concerning the existence and frequency of planets around stars, other than our own, was absent. Since this time, the detection of extrasolar planets from Jupiter-sized to most recently Earth-sized worlds has blossomed and we are finally able to shed light on the plurality of Earth-like, habitable planets in the cosmos. Extrasolar moons may also be frequent habitable worlds but their detection or even systematic pursuit remains lacking in the current literature. Here, we present a description of the first systematic search for extrasolar moons as part of a new observational project called "The Hunt for Exomoons with Kepler" (HEK). The HEK project distills the entire list of known transiting planet candidates found by Kepler (2326 at the time of writing) down to the most promising candidates for hosting a moon. Selected targets are fitted using a multimodal nested sampling algorithm coupled with a planet-with-moon light curve modelling rou...
Previous works have identified families halos by an analysis in proper elements domains, or by us... more Previous works have identified families halos by an analysis in proper elements domains, or by using Sloan Digital Sky Survey-Moving Object Catalog data, fourth release (SDSS-MOC4) multi-band photometry to infer the asteroid taxonomy, or by a combination of the two methods. The limited number of asteroids for which geometric albedo was known until recently discouraged in the past the extensive use of this additional parameter, which is however of great importance in identifying an asteroid taxonomy. The new availability of geometric albedo data from the Wide-field Infrared Survey Explorer (WISE) mission for about 100,000 asteroids significantly increased the sample of objects for which such information, with some errors, is now known. In this work we proposed a new method to identify families halos in a multi-domain space composed by proper elements, SDSS-MOC4 (a*,i-z) colors, and WISE geometric albedo for the whole main belt (and the Hungaria and Cybele orbital regions). Assuming t...
V-type asteroids are bodies whose surfaces are constituted of basalt. In the Main Asteroid Belt, ... more V-type asteroids are bodies whose surfaces are constituted of basalt. In the Main Asteroid Belt, most of these asteroids are assumed to come from the basaltic crust of Asteroid (4) Vesta. This idea is mainly supported by (i) the fact that almost all the known V-type asteroids are in the same region of the belt as (4) Vesta, i.e., the inner belt (semi-major axis 2.1<a<2.5 AU), (ii) the existence of a dynamical asteroid family associated to (4) Vesta, and (iii) the observational evidence of at least one large craterization event on Vesta's surface. One V-type asteroid that is difficult to fit in this scenario is (1459) Magnya, located in the outer asteroid belt, i.e., too far away from (4) Vesta as to have a real possibility of coming from it. The recent discovery of the first V-type asteroid in the middle belt (2.5<a<2.8 AU), (21238) 1995WV7 [Binzel, R.P., Masi, G., Foglia, S., 2006. Bull. Am. Astron. Soc. 38, 627; Hammergren, M., Gyuk, G., Puckett, A., 2006. ArXiv e-...
Evidence in the Solar System suggests that the giant planets underwent an epoch of radial migrati... more Evidence in the Solar System suggests that the giant planets underwent an epoch of radial migration that was very rapid, with an e-folding timescale shorter than 1~Myr. It is probable that the cause of this migration was that the giant planets experienced an orbital instability that caused them to encounter each other, resulting in radial migration. Several works suggest that this dynamical instability occurred `late', long after all the planets had formed and the solar nebula had dissipated. Assuming that the terrestrial planets had already formed, then their orbits would have been affected by the migration of the giant planets. As a result, how did the orbits of the terrestrial planets change? And can we use this migration to obtain information on the primordial orbits of the terrestrial planets? We directly model a large number of terrestrial planet systems and their response to giant planet migration. We study the change in the Angular Momentum Deficit (AMD) of the terrstria...
KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 an... more KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 and KOI-884, the observed Transit Timing Variations (TTVs) of the inner transiting planet are used to detect an outer non-transiting planet. The outer planet in KOI-884 is 2.6 Jupiter masses and has the orbital period just narrow of the 3:1 resonance with the inner planet (orbital period ratio 2.93). The distribution of parameters inferred from KOI-319.01's TTVs is bimodal with either a 1.6 Neptune-mass (M_N) planet wide of the 5:3 resonance (period 80.1 d) or a 1 Saturn-mass planet wide of the 7:3 resonance (period 109.2 d). The radial velocity measurements can be used in this case to determine which of these parameter modes is correct. KOI-227.01's TTVs with large 10 hour amplitude can be obtained for planetary-mass companions in various major resonances. Based on the Bayesian evidence, the current TTV data favor the outer 2:1 resonance with a companion mass 1.5 M_N, but this sol...
Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bendin... more Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bending from the equator to the orbital plane of Saturn. The orbital inclination of Iapetus to the local Laplace plane is ~8 deg, which is unexpected, because the inclination should be ~0 if Iapetus formed from a circumplanetary disk on the Laplace surface. It thus appears that some process has pumped up Iapetus's inclination while leaving its eccentricity near zero (e=0.03 at present). Here we examined the possibility that Iapetus's inclination was excited during the early solar system instability when encounters between Saturn and ice giants occurred. We found that the dynamical effects of planetary encounters on Iapetus's orbit sensitively depend on the distance of the few closest encounters. In four out of ten instability cases studied here, the orbital perturbations were too large to be plausible. In one case, Iapetus's orbit was practically unneffected. In the remaining f...
The Nice model of the dynamical instability and migration of the giant planets can explain many p... more The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present Solar System, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites, and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorny & Morbidelli (2012) that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits we...
Proceedings of the International Astronomical Union, 2006
The effect of the space weathering on the spectral properties of the S-complex asteroids (both Ma... more The effect of the space weathering on the spectral properties of the S-complex asteroids (both Main Belt bodies and near-Earth asteroids) has been widely discussed in recent times. It has also shown that the evolution of spectral properties of planet-crossing bodies, and in particular of near-Earth asteroids (NEAs), is also affected by other physical processes, such as tidal resurfacing due to close encounters with planetary bodies. In this paper we show how to combine previous analyses with the purpose of obtaining a global model for NEAs space weathering.
Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bending fr... more Saturn's moon Iapetus has an orbit in a transition region where the Laplace surface is bending from the equator to the orbital plane of Saturn. The orbital inclination of Iapetus to the local Laplace plane is ≃ 8 • , which is unexpected, because the inclination should be ≃ 0 if Iapetus formed from a circumplanetary disk on the Laplace surface. It thus appears that some process has pumped up Iapetus's inclination while leaving its eccentricity near zero (e ≃ 0.03 at present). Here we examined the possibility that Iapetus's inclination was excited during the early solar system instability when encounters between Saturn and ice giants occurred. We found that the dynamical effects of planetary encounters on Iapetus's orbit sensitively depend on the distance of the few closest encounters. In four out of ten instability cases studied here, the orbital perturbations were too large to be plausible. In one case, Iapetus's orbit was practically unneffected. In the remaining five cases, the perturbations of Iapetus's inclination were adequate to explain its present value. In three of these cases, however, Iapetus's eccentricity was excited to >0.1-0.25, and it is not clear whether it could have been damped to its present value (≃ 0.03) by some subsequent process (e.g., tides and dynamical friction from captured irregular satellites do not seem to be strong enough). Our results therefore imply that only 2 out of 10 instability cases (∼20%) can excite Iapetus's inclination to its present value (∼30% of trials lead to >5 • ) while leaving its orbital eccentricity low.
Proceedings of the International Astronomical Union, 2005
Non-gravitational perturbations, regardless being many orders of magnitude weaker than gravity, h... more Non-gravitational perturbations, regardless being many orders of magnitude weaker than gravity, hold keys to fully understand the evolution of small Solar System bodies. This is because individual bodies, or their entire groups, manifest traces of a long-term accumulated changes by these effects.
Proceedings of the International Astronomical Union, 2004
... Non-gravitational perturbations and evolution of the asteroid main belt ... Page 3. Non-gravi... more ... Non-gravitational perturbations and evolution of the asteroid main belt ... Page 3. Non-gravitational perturbations... 147 1969; O’Brien & Greenberg 2003). ...
KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 an... more KOI-227, KOI-319 and KOI-884 are identified here as (at least) two planet systems. For KOI-319 and KOI-884, the observed Transit Timing Variations (TTVs) of the inner transiting planet are used to detect an outer non-transiting planet. The outer planet in KOI-884 is ≃2.6 Jupiter masses and has the orbital period just narrow of the 3:1 resonance with the inner planet (orbital period ratio 2.93). The distribution of parameters inferred from KOI-319.01's TTVs is bimodal with either a ≃1.6 Neptune-mass (M N ) planet wide of the 5:3 resonance (period 80.1 d) or a ≃1 Saturn-mass planet wide of the 7:3 resonance (period 109.2 d). The radial velocity measurements can be used in this case to determine which of these parameter modes is correct. KOI-227.01's TTVs with large ≃10 hour amplitude can be obtained for planetary-mass companions in various major resonances. Based on the Bayesian evidence, the current TTV data favor the outer 2:1 resonance with a companion mass ≃1.5 M N , but this solution implies a very large density of KOI-227.01. The inner and outer 3:2 resonance solutions with sub-Neptune-mass companions are physically more plausible, but will need to be verified.
ABSTRACT Embedded in the gaseous protoplanetary disk, Jupiter and Saturn naturally become trapped... more ABSTRACT Embedded in the gaseous protoplanetary disk, Jupiter and Saturn naturally become trapped in 3:2 resonance and migrate outward. This serves as the basis of the Grand Tack model. However, previous hydrodynamical simulations were restricted to isothermal disks, with moderate aspect ratio and viscosity. Here we simulate the orbital evolution of the gas giants in disks with viscous heating and radiative cooling. We find that Jupiter and Saturn migrate outward in 3:2 resonance in modest-mass ($M_{disk} \approx M_{MMSN}$, where MMSN is the &quot;minimum-mass solar nebula&quot;) disks with viscous stress parameter $\alpha$ between $10^{-3}$ and $10^{-2} $. In disks with relatively low-mass ($M_{disk} \lesssim M_{MMSN}$) , Jupiter and Saturn get captured in 2:1 resonance and can even migrate outward in low-viscosity disks ($\alpha \le 10^{-4}$). Such disks have a very small aspect ratio ($h\sim 0.02-0.03$) that favors outward migration after capture in 2:1 resonance, as confirmed by isothermal runs which resulted in a similar outcome for $h \sim 0.02$ and $\alpha \le 10^{-4}$. We also performed N-body runs of the outer Solar System starting from the results of our hydrodynamical simulations and including 2-3 ice giants. After dispersal of the gaseous disk, a Nice model instability starting with Jupiter and Saturn in 2:1 resonance results in good Solar Systems analogs. We conclude that in a cold Solar Nebula, the 2:1 resonance between Jupiter and Saturn can lead to outward migration of the system, and this may represent an alternative scenario for the evolution of the Solar System.
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Papers by David Nesvorný