Publication Search Results

ID: 156328
Type: article
Authors: Patra, Kishore C.; Winn, Joshua N.; Holman, Matthew J.; Gillon, Michael; Burdanov, Artem; Jehin, Emmanuel; Delrez, Laetitia; Pozuelos, Francisco J.; Barkaoui, Khalid; Benkhaldoun, Zouhair; Narita, Norio; Fukui, Akihiko; Kusakabe, Nobuhiko; Kawauchi, Kiyoe; Terada, Yuka; Bouma, L. G.; Weinberg, Nevin N.; Broome, Madelyn
Abstract: Many of the known hot Jupiters are formally unstable to tidal orbital decay. The only hot Jupiter for which orbital decay has been directly detected is WASP-12, for which transit-timing measurements spanning more than a decade have revealed that the orbital period is decreasing at a rate of ${dP}/{dt}\approx {10}^{-9}, corresponding to a reduced tidal quality factor of about 2 × 10⁵. Here, we present a compilation of transit-timing data for WASP-12 and 11 other systems that are especially favorable for detecting orbital decay: KELT-16; WASP-18, 19, 43, 72, 103, 114, and 122; HAT-P-23; HATS-18; and OGLE-TR-56. For most of these systems we present new data that extend the time baseline over which observations have been performed. None of the systems besides WASP-12 display convincing evidence for period changes, with typical upper limits on dP/dt on the order of 10^-9 or 10^-10, and lower limits on the reduced tidal quality factor on the order of 10⁵. One possible exception is WASP-19, which shows a statistically significant trend, although it may be a spurious effect of starspot activity. Further observations are encouraged.

ID: 156222
Type: article
Authors: Spencer, J. R.; Stern, S. A.; Moore, J. M.; Weaver, H. A.; Singer, K. N.; Olkin, C. B.; Verbiscer, A. J.; McKinnon, W. B.; Parker, J. Wm; Beyer, R. A.; Keane, J. T.; Lauer, T. R.; Porter, S. B.; White, O. L.; Buratti, B. J.; El-Maarry, M. R.; Lisse, C. M.; Parker, A. H.; Throop, H. B.; Robbins, S. J.; Umurhan, O. M.; Binzel, R. P.; Britt, D. T.; Buie, M. W.; Cheng, A. F.; Cruikshank, D. P.; Elliott, H. A.; Gladstone, G. R.; Grundy, W. M.; Hill, M. E.; Horanyi, M.; Jennings, D. E.; Kavelaars, J. J.; Linscott, I. R.; McComas, D. J.; McNutt, R. L.; Protopapa, S.; Reuter, D. C.; Schenk, P. M.; Showalter, M. R.; Young, L. A.; Zangari, A. M.; Abedin, A. Y.; Beddingfield, C. B.; Benecchi, S. D.; Bernardoni, E.; Bierson, C. J.; Borncamp, D.; Bray, V. J.; Chaikin, A. L.; Dhingra, R. D.; Fuentes, C.; Fuse, T.; Gay, P. L.; Gwyn, S. D. J.; Hamilton, D. P.; Hofgartner, J. D.; Holman, Matthew J.; Howard, A. D.; Howett, C. J. A.; Karoji, H.; Kaufmann, D. E.; Kinczyk, M.; May, B. H.; Mountain, M.; Pätzold, M.; Petit, J. M.; Piquette, M. R.; Reid, I. N.; Reitsema, H. J.; Runyon, K. D.; Sheppard, S. S.; Stansberry, J. A.; Stryk, T.; Tanga, P.; Tholen, D. J.; Trilling, D. E.; Wasserman, L. H.
Abstract: The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer- long contact binary (486958) Arrokoth (provisional designation 2014 MU₆₉). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.

ID: 155698
Type: article
Authors: Yee, Samuel W.; Winn, Joshua N.; Knutson, Heather A.; Patra, Kishore C.; Vissapragada, Shreyas; Zhang, Michael M.; Holman, Matthew J.; Shporer, Avi; Wright, Jason T.
Abstract: WASP-12b is a transiting hot Jupiter on a 1.09 day orbit around a late-F star. Since the planet's discovery in 2008, the time interval between transits has been decreasing by 29 ± 2 ms yr⁻¹. This is a possible sign of orbital decay, although the previously available data left open the possibility that the planet's orbit is slightly eccentric and is undergoing apsidal precession. Here, we present new transit and occultation observations that provide more decisive evidence for orbital decay, which is favored over apsidal precession by a {{∆ }}{BIC} of 22.3 or Bayes factor of 70,000. We also present new radial-velocity data that rule out the Rømer effect as the cause of the period change. This makes WASP-12 the first planetary system for which we can be confident that the orbit is decaying. The decay timescale for the orbit is P/\dot{P}=3.25+/- 0.23 {Myr}. Interpreting the decay as the result of tidal dissipation, the modified stellar tidal quality factor is {Q}_\star ^{\prime }=1.8× {10}⁵.

ID: 155244
Type: article
Authors: Goldberg, Max; Hadden, Sam; Payne, Matthew J.; Holman, Matthew J.
Abstract: In this paper we investigate systems previously identified to exhibit transit timing variations in Kepler data, with the goal of predicting the expected improvements to the mass and eccentricity constraints that will arise from combining Kepler data with future data from the Transiting Exoplanet Survey Satellite (TESS) mission. We advocate for the use of the Kullback-Leibler (KL) divergence as a means to quantify improvements in the measured constraints. Compared to the original Kepler data, the TESS data will have a lower signal-to-noise ratio, rendering some of the planetary transits undetectable, and lowering the accuracy with which the transit mid-time can be estimated. Despite these difficulties, out of the 55 systems (containing 143 planets) investigated, we predict that the collection of short-cadence data by TESS will be of significant value (i.e., it will improve the mass uncertainty such that the KL divergence is ≳0.1) for approximately 6-14 planets during the nominal mission, with the range primarily driven by the uncertain precision with which transit mid-times will be recovered from TESS data. In an extended mission this would increase to a total of approximately 12-25 planets.

ID: 154625
Type: article
Authors: Hadden, Sam; Barclay, Thomas; Payne, Matthew J.; Holman, Matthew J.
Abstract: We consider the potential for the Transiting Exoplanet Survey Satellite (TESS) to detect transit timing variations (TTVs) during both its nominal and extended mission phases. Building on previous estimates of the overall yield of planetary systems from the TESS mission, we predict that during its nominal two-year mission, TESS will observe measurable TTVs in ̃30 systems, from which { \mathcal O }(10) planet will get precise mass measurements from TTVs alone, ̃5 planets will have significant constraints placed on their masses from TTVs, and over a dozen systems will be singly transiting TTV systems. We consider a number of different extended mission scenarios, and predict that in a typical scenario, an extended mission will allow TESS to increase the number of systems with measurable TTVs to a total of ̃90, from which ̃15 planets will have precise mass measurements, another ̃15 will have significant constraints placed on their masses, and ̃60 will be singly transiting TTV systems. We also describe how follow-up transit observations of multiplanet systems discovered by the TESS mission can be optimally planned to maximize TTV mass and eccentricity constraints.

ID: 152921
Type: article
Authors: Keys, Sonia; Vereš, Peter; Payne, Matthew J.; Holman, Matthew J.; Jedicke, Robert; Williams, Gareth V.; Spahr, Tim; Asher, David J.; Hergenrother, Carl
Abstract: We describe the {digest}2 software package, a fast, short-arc orbit classifier for small solar system bodies. The {digest}2 algorithm has been serving the community for more than 13 yr. The code provides a score, {D}₂, which represents a pseudo-probability that a tracklet belongs to a given solar system orbit type. {digest}2 is primarily used as a classifier for Near-Earth Object (NEO) candidates, to identify those to be prioritized for follow-up observation. We describe the historical development of {digest}2 and demonstrate its use on real and synthetic data. We find that {digest}2 can accurately and precisely distinguish NEOs from non-NEOs. At the time of detection, 14% of NEO tracklets and 98.5% of non-NEOs tracklets have {D}₂ below the critical value of {D}₂=65.94 % of our simulated NEOs achieved the maximum {D}₂=100 % and 99.6% of NEOs achieved {D}₂≥slant 65 at least once during the simulated 10-year timeframe. We demonstrate that {D}₂ varies as a function of time, rate of motion, magnitude and sky-plane location, and show that NEOs tend to have lower {D}₂ at low Solar elongations close to the ecliptic. We use our findings to recommend future development directions for the {digest}2 code.

ID: 149181
Type: article
Authors: Holman, Matthew J.; Payne, Matthew J.; Blankley, Paul; Janssen, Ryan; Kuindersma, Scott
Abstract: We present HelioLinC, a novel approach to the minor planet linking problem. Our heliocentric transformation-and-propagation algorithm clusters tracklets at common epochs, allowing for the efficient identification of tracklets that represent the same minor planet. This algorithm scales as { \mathcal O }(N{log}N) with the number of tracklets N, a significant advance over standard methods, which scale as { \mathcal O }({N}³). This overcomes one of the primary computational bottlenecks faced by current and future asteroid surveys. We apply our algorithm to the Minor Planet Center’s Isolated Tracklet File, establishing orbits for more than 200,000 new minor planets. A detailed analysis of the influence of false detections on the efficiency of our approach, along with an examination of detection biases, will be presented in future work.

ID: 146151
Type: article
Authors: Holman, Matthew J.; Payne, Matthew J.; Fraser, Wesley; Lacerda, Pedro; Bannister, Michele T.; Lackner, Michael; Chen, Ying-Tung; Lin, Hsing Wen; Smith, Kenneth W.; Kokotanekova, Rosita; Young, David; Chambers, K.; Chastel, S.; Denneau, L.; Fitzsimmons, A.; Flewelling, H.; Grav, Tommy; Huber, M.; Induni, Nick; Kudritzki, Rolf-Peter; Krolewski, Alex; Jedicke, R.; Kaiser, N.; Lilly, E.; Magnier, E.; Mark, Zachary; Meech, K. J.; Micheli, M.; Murray, Daniel; Parker, Alex; Protopapas, Pavlos; Ragozzine, Darin; Veres, Peter; Wainscoat, R.; Waters, C.; Weryk, R.
Abstract: We report the discovery of an H _r = 3.4 ± 0.1 dwarf planet candidate by the Pan-STARRS Outer Solar System Survey. 2010 JO₁₇₉ is red with (g ‑ r) = 0.88 ± 0.21, roughly round, and slowly rotating, with a period of 30.6 hr. Estimates of its albedo imply a diameter of 600–900 km. Observations sampling the span between 2005 and 2016 provide an exceptionally well determined orbit for 2010 JO₁₇₉, with a semimajor axis of 78.307 ± 0.009 au; distant orbits known to this precision are rare. We find that 2010 JO₁₇₉ librates securely within the 21:5 mean-motion resonance with Neptune on 100 Myr timescales, joining the small but growing set of known distant dwarf planets on metastable resonant orbits. These imply a substantial trans-Neptunian population that shifts between stability in high-order resonances, the detached population, and the eroding population of the scattering disk.

ID: 150205
Type: article
Authors: Li, Gongjie; Hadden, Samuel; Payne, Matthew; Holman, Matthew J.
Abstract: The existence of Planet Nine has been suggested to explain the pericenter clustering of extreme trans-Neptunian objects (TNOs). However, the underlying dynamics involving Planet Nine, test particles, and Neptune is rich, and it remains unclear which dynamical processes lead to the alignment and how they depend on the properties of Planet Nine. Here we investigate the secular interactions between an eccentric outer perturber and TNOs starting in a near-coplanar configuration. We find that a large number of TNOs could survive outside of mean-motion resonances at 4 Gyr, which differs from previous results obtained in the exact coplanar case with Neptune being treated as a quadrupole potential. In addition, secular dynamics leads to the orbital clustering seen in N-body simulations. We find that a near-coplanar Planet Nine can flip TNO orbital planes, and when this happens, the geometrical longitudes of pericenter of the TNOs librate around 180° during the flip. Orbital precession caused by the inner giant planets can suppress the flips while keeping the longitude of pericenter librating when 30 au ≲ r _p ≲ 80 au and a ≳ 250 au. This results in the alignment of the pericenter of the low-inclination TNOs (i ≲ 40°). We find that the anti-aligned population and flipped orbits could be produced by an eccentric (e ₉ ≳ 0.4) outer planet of ∼10 M _⊕ in a wide a ₉ ≳ 400 ∼ 800 au orbit. Future surveys of the high-inclination TNOs will help further constrain the properties of possible outer planets.

ID: 147923
Type: article
Authors: Veres, Peter; Payne, Matthew J.; Holman, Matthew J.; Farnocchia, Davide; Williams, Gareth V.; Keys, Sonia; Boardman, Ian
Abstract: We studied the Near-Earth Asteroid (NEA) candidates posted on the Minor Planet Center's Near-Earth Object Confirmation Page (NEOCP) between years 2013 and 2016. Out of more than 17000 NEA candidates, while the majority became either new discoveries or were associated with previously known objects, about 11% were unable to be followed-up or confirmed. We further demonstrate that of the unconfirmed candidates, 926 ± 50 are likely to be NEAs, representing 18% of discovered NEAs in that period. Only 11% (~93) of the unconfirmed NEA candidates were large (having absolute magnitude H < 22). To identify the reasons why these NEAs were not recovered, we analyzed those from the most prolific asteroid surveys: Pan-STARRS, the Catalina Sky Survey, the Dark Energy Survey, and the Space Surveillance Telescope. We examined the influence of plane-of-sky positions and rates of motion, brightnesses, submission delays, and computed absolute magnitudes, as well as correlations with the phase of the moon and seasonal effects. We find that delayed submission of newly discovered NEA candidate to the NEOCP drove a large fraction of the unconfirmed NEA candidates. A high rate of motion was another significant contributing factor. We suggest that prompt submission of suspected NEA discoveries and rapid response to fast-moving targets and targets with fast growing ephemeris uncertainty would allow better coordination among dedicated follow-up observers, decrease the number of unconfirmed NEA candidates, and increase the discovery rate of NEAs.

ID: 143829
Type: article
Authors: Patra, Kishore C.; Winn, Joshua N.; Holman, Matthew J.; Yu, Liang; Deming, Drake; Dai, Fei
Abstract: We present new transit and occultation times for the hot Jupiter WASP-12b. The data are compatible with a constant period derivative: \dot{P}=-29+/- 3 ms yr^-1 and P/\dot{P}=3.2 {Myr}. However, it is difficult to tell whether we have observed orbital decay or a portion of a 14-year apsidal precession cycle. If interpreted as decay, the star’s tidal quality parameter {Q}_\star is about 2× {10}⁵. If interpreted as precession, the planet’s Love number is 0.44 ± 0.10. Orbital decay appears to be the more parsimonious model: it is favored by {{Δ }}{χ }²=5.5 despite having two fewer free parameters than the precession model. The decay model implies that WASP-12 was discovered within the final ˜0.2% of its existence, which is an unlikely coincidence but harmonizes with independent evidence that the planet is nearing disruption. Precession does not invoke any temporal coincidence, but it does require some mechanism to maintain an eccentricity of ≈ 0.002 in the face of rapid tidal circularization. To distinguish unequivocally between decay and precession will probably require a few more years of monitoring. Particularly helpful will be occultation timing in 2019 and thereafter.

ID: 142307
Type: article
Authors: Payne, Matthew J.; Veras, Dimitri; Gansicke, Boris T.; Holman, Matthew J.
Abstract: Roughly 1000 white dwarfs are known to be polluted with planetary material, and the progenitors of this material are typically assumed to be asteroids. The dynamical architectures which perturb asteroids into white dwarfs are still unknown, but may be crucially dependent on moons liberated from parent planets during post-main-sequence gravitational scattering. Here, we trace the fate of these exomoons, and show that they more easily achieve deep radial incursions towards the white dwarf than do scattered planets. Consequently, moons are likely to play a significant role in white dwarf pollution, and in some cases may be the progenitors of the pollution itself.

ID: 140735
Type: article
Authors: Chen, Ying-Tung; Lin, Hsing Wen; Holman, Matthew J.; Payne, Matthew J.; Fraser, Wesley C.; Lacerda, Pedro; Ip, Wing-Huen; Chen, Wen-Ping; Kudritzki, Rolf-Peter; Jedicke, Robert; Wainscoat, Richard J.; Tonry, John L.; Magnier, Eugene A.; Waters, Christopher; Kaiser, Nick; Wang, Shiang-Yu; Lehner, Matthew J.
Abstract: Although the majority of Centaurs are thought to have originated in the scattered disk, with the high-inclination members coming from the Oort cloud, the origin of the high-inclination component of trans-Neptunian objects (TNOs) remains uncertain. We report the discovery of a retrograde TNO, which we nickname “Niku,” detected by the Pan-STARRS 1 Outer Solar System Survey. Our numerical integrations show that the orbital dynamics of Niku are very similar to that of 2008 KV₄₂ (Drac), with a half-life of ˜500 Myr. Comparing similar high-inclination TNOs and Centaurs (q > 10 au, a 60°), we find that these objects exhibit a surprising clustering of ascending node, and occupy a common orbital plane. This orbital configuration has high statistical significance: 3.8-σ. An unknown mechanism is required to explain the observed clustering. This discovery may provide a pathway to investigating a possible reservoir of high-inclination objects.

ID: 141974
Type: article
Authors: Hastings, Danielle M.; Ragozzine, Darin; Fabrycky, Daniel C.; Burkhart, Luke D.; Fuentes, Cesar; Margot, Jean-Luc; Brown, Michael E.; Holman, Matthew
Abstract: Hi’iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi’iaka to be ~9.8 hr (double peaked). This is ~120 times faster than its orbital period, creating new questions about the formation of this system and possible tidal evolution. The rapid rotation suggests that Hi’iaka could have a significant obliquity and spin precession that could be visible in light curves within a few years. We then turn to an investigation of what we learn about the (currently unclear) formation of the Haumea system and family based on this unexpectedly rapid rotation rate. We explore the importance of the initial semimajor axis and rotation period in tidal evolution theory and find that they strongly influence the time required to despin to synchronous rotation, relevant to understanding a wide variety of satellite and binary systems. We find that despinning tides do not necessarily lead to synchronous spin periods for Hi’iaka, even if it formed near the Roche limit. Therefore, the short rotation period of Hi’iaka does not rule out significant tidal evolution. Hi’iaka’s spin period is also consistent with formation near its current location and spin-up due to Haumea-centric impactors.

ID: 142019
Type: article
Authors: Holman, Matthew J.; Payne, Matthew J.
Abstract: We examine the tidal perturbations induced by a possible additional, distant planet in the solar system on the distance between the Earth and the Cassini spacecraft. We find that measured range residuals alone can significantly constrain the sky position, distance, and mass of the perturbing planet to sections of the sky essentially orthogonal to the orbit of Saturn. When we combine these constraints from tidal perturbations with the dynamical constraints from Batygin & Brown and Brown & Batygin, we further constrain the allowed location of the perturbing planet to a region of the sky approximately centered on (R.A., decl.) = (40°, -15°) and extending ˜20° in all directions.

ID: 142021
Type: article
Authors: Holman, Matthew J.; Payne, Matthew J.
Abstract: We use astrometry of Pluto and other trans-neptunian objects to constrain the sky location, distance, and mass of the possible additional planet (Planet Nine) hypothesized by Batygin & Brown. We find that over broad regions of the sky, the inclusion of a massive, distant planet degrades the fits to the observations. However, in other regions, the fits are significantly improved by the addition of such a planet. Our best fits suggest a planet that is either more massive or closer than argued for by Batygin & Brown based on the orbital distribution of distant trans-neptunian objects (or by Fienga et al. based on range measured to the Cassini spacecraft). The trend to favor larger and closer perturbing planets is driven by the residuals to the astrometry of Pluto, remeasured from photographic plates using modern stellar catalogs, which show a clear trend in decl. over the course of two decades, that drive a preference for large perturbations. Although this trend may be the result of systematic errors of unknown origin in the observations, a possible resolution is that the decl. trend may be due to perturbations from a body, in addition to Planet Nine, that is closer to Pluto but less massive than Planet Nine.

ID: 141915
Type: article
Authors: Li, Gongjie; Holman, Matthew J.; Tao, Molei
Abstract: Studying newly discovered circumbinary planetary systems improves our understanding of planetary system formation. Learning the architectural properties of these systems is essential for constraining the different formation mechanisms. We first revisit the stability limit of circumbinary planets. Next, we focus on eclipsing stellar binaries and obtain an analytical expression for the transit probability in a realistic setting, where a finite observation period and planetary orbital precession are included. Our understanding of the architectural properties of the currently observed transiting systems is then refined, based on Bayesian analysis and a series of tested hypotheses. We find that (1) it is not a selection bias that the innermost planets reside near the stability limit for eight of the nine observed systems, and this pile-up is consistent with a log uniform distribution of the planetary semimajor axis; (2) it is not a selection bias that the planetary and stellar orbits are nearly coplanar (?3°), and this—along with previous studies—may imply an occurrence rate of circumbinary planets similar to that of single star systems; (3) the dominance of observed circumbinary systems with only one transiting planet may be caused by selection effects; (4) formation mechanisms involving Lidov-Kozai oscillations, which may produce misalignment and large separation between planets and stellar binaries, are consistent with the lack of transiting circumbinary planets around short-period stellar binaries, in agreement with previous studies. As a consequence of (4), eclipse timing variations may better suit the detection of planets in such configurations.

ID: 141922
Type: article
Authors: Lin, Hsing Wen; Chen, Ying-Tung; Holman, Matthew J.; Ip, Wing-Huen; Payne, M. J.; Lacerda, P.; Fraser, W. C.; Gerdes, D. W.; Bieryla, A.; Sie, Z. -F; Chen, W. -P; Burgett, W. S.; Denneau, L.; Jedicke, R.; Kaiser, N.; Magnier, E. A.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.
Abstract: In this work, we report the detection of seven Neptune Trojans (NTs) in the Pan-STARRS 1 (PS1) survey. Five of these are new discoveries, consisting of four L4 Trojans and one L5 Trojan. Our orbital simulations show that the L5 Trojan stably librates for only several million years. This suggests that the L5 Trojan must be of recent capture origin. On the other hand, all four new L4 Trojans stably occupy the 1:1 resonance with Neptune for more than 1 Gyr. They can, therefore, be of primordial origin. Our survey simulation results show that the inclination width of the NT population should be between 7° and 27° at >95% confidence, and most likely ~11°. In this paper, we describe the PS1 survey, the Outer Solar System pipeline, the confirming observations, and the orbital/physical properties of the new NTs.

ID: 142017
Type: article
Authors: MacDonald, Mariah G.; Ragozzine, Darin; Fabrycky, Daniel C.; Ford, Eric B.; Holman, Matthew J.; Isaacson, Howard T.; Lissauer, Jack J.; Lopez, Eric D.; Mazeh, Tsevi; Rogers, Leslie; Rowe, Jason F.; Steffen, Jason H.; Torres, Guillermo
Abstract: Kepler has discovered hundreds of systems with multiple transiting exoplanets which hold tremendous potential both individually and collectively for understanding the formation and evolution of planetary systems. Many of these systems consist of multiple small planets with periods less than ~50 days known as Systems with Tightly spaced Inner Planets, or STIPs. One especially intriguing STIP, Kepler-80 (KOI-500), contains five transiting planets: f, d, e, b, and c with periods of 1.0, 3.1, 4.6, 7.1, and 9.5 days, respectively. We provide measurements of transit times and a transit timing variation (TTV) dynamical analysis. We find that TTVs cannot reliably detect eccentricities for this system, though mass estimates are not affected. Restricting the eccentricity to a reasonable range, we infer masses for the outer four planets (d, e, b, and c) to be {6.75}_-0.51^+0.69, {4.13}_-0.95^+0.81, {6.93}_-0.70^+1.05, and {6.74}_-0.86^+1.23 Earth masses, respectively. The similar masses but different radii are consistent with terrestrial compositions for d and e and ~2% H/He envelopes for b and c. We confirm that the outer four planets are in a rare dynamical configuration with four interconnected three-body resonances that are librating with few degree amplitudes. We present a formation model that can reproduce the observed configuration by starting with a multi-resonant chain and introducing dissipation. Overall, the information-rich Kepler-80 planets provide an important perspective into exoplanetary systems.

ID: 139302
Type: article
Authors: Payne, Matthew J.; Veras, Dimitri; Holman, Matthew J.; Gänsicke, Boris T.
Abstract: Previous studies indicate that more than a quarter of all white dwarf (WD) atmospheres are polluted by remnant planetary material, with some WDs being observed to accrete the mass of Pluto in 10⁶ yr. The short sinking time-scale for the pollutants indicates that the material must be frequently replenished. Moons may contribute decisively to this pollution process if they are liberated from their parent planets during the post-main-sequence evolution of the planetary systems. Here, we demonstrate that gravitational scattering events amongst planets in WD systems easily trigger moon ejection. Repeated close encounters within tenths of planetary Hill radii are highly destructive to even the most massive, close-in moons. Consequently, scattering increases both the frequency of perturbing agents in WD systems, as well as the available mass of polluting material in those systems, thereby enhancing opportunities for collision and fragmentation and providing more dynamical pathways for smaller bodies to reach the WD. Moreover, during intense scattering, planets themselves have pericentres with respect to the WD of only a fraction of an astronomical unit, causing extreme Hill-sphere contraction, and the liberation of moons into WD-grazing orbits. Many of our results are directly applicable to exomoons orbiting planets around main-sequence stars.