Generation of Highly Inclined Trans-Neptunian Objects by Planet Nine

Generation of Highly Inclined Trans-Neptunian Objects by Planet Nine

Authors:

Batygin et al

Abstract:

The trans-Neptunian region of the solar system exhibits an intricate dynamical structure, much of which can be explained by an instability-driven orbital history of the giant planets. However, the origins of a highly inclined, and in certain cases retrograde, population of trans-Neptunian objects remain elusive within the framework of this evolutionary picture. In this work, we show that the existence of a distant, Neptune-like planet that resides on an eccentric and mildly inclined orbit fully accounts for the anomalous component the trans-Neptunian orbital distribution. Adopting the same parameters for Planet Nine as those previously invoked to explain the clustering of distant Kuiper belt orbits in physical space, we carry out a series of numerical experiments which elucidate the physical process though which highly inclined Kuiper belt objects with semi-major axes smaller than 100 AU are generated. The identified dynamical pathway demonstrates that enigmatic members of the Kuiper belt such as Drac and Niku are derived from the extended scattered disk of the solar system.

Doubts About Planet Nine?

Consequences of a Distant Massive Planet on the Large Semi-major Axis Trans-Neptunian Objects

Authors:

Shankman et al

Abstract:

We explore the distant giant planet hypothesis by integrating the large semi-major axis, large pericenter Trans-Neptunian Objects (TNOs) in the presence of the giant planets and an external perturber whose orbit is consistent with the proposed distant, eccentric, and inclined giant planet, so called planet 9. We find that TNOs with semi-major axes greater than 250 au experience some longitude of perihelion shepherding, but that a generic outcome of such evolutions is that the TNOs evolve to larger pericenter orbits, and commonly get raised to retrograde inclinations. This pericenter and inclination evolution requires a massive disk of TNOs (tens of M$_\Earth$) in order to explain the detection of the known sample today. Some of the highly inclined orbits produced by the examined perturbers will be inside of the orbital parameter space probed by prior surveys, implying a missing signature of the 9th planet scenario. The distant giant planet scenarios explored in this work do not reproduce the observed signal of simultaneous clustering in argument of pericenter, longitude of the ascending node, and longitude of perihelion in the region of the known TNOs.

If Planet Nine Exists, it Could be a 'Disaster' After the Sun Dies

The solar system could be thrown into disaster when the sun dies if the mysterious 'Planet Nine' exists, according to research from the University of Warwick.

Dr Dimitri Veras in the Department of Physics has discovered that the presence of Planet Nine - the hypothetical planet which may exist in the outer Solar System - could cause the elimination of at least one of the giant planets after the sun dies, hurling them out into interstellar space through a sort of 'pinball' effect.

When the sun starts to die in around seven billion years, it will blow away half of its own mass and inflate itself -- swallowing the Earth -- before fading into an ember known as a white dwarf. This mass ejection will push Jupiter, Saturn, Uranus and Neptune out to what was assumed a safe distance.

However, Dr. Veras has discovered that the existence of Planet Nine could rewrite this happy end-ing. He found that Planet Nine might not be pushed out in the same way, and in fact might instead be thrust inward into a death dance with the solar system's four known giant planets -- most notably Uranus and Neptune. The most likely result is ejection from the solar system, forever.

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Would the Presence of Planet Nine Explain the Solar Rotation/ Plane of the Ecliptic Misalignment?

Solar Obliquity Induced by Planet Nine

Authors:

Bailey et al

Abstract:

The six-degree obliquity of the sun suggests that either an asymmetry was present in the solar system's formation environment, or an external torque has misaligned the angular momentum vectors of the sun and the planets. However, the exact origin of this obliquity remains an open question. Batygin & Brown (2016) have recently shown that the physical alignment of distant Kuiper Belt orbits can be explained by a 5-20 Earth-mass planet on a distant, eccentric, and inclined orbit, with an approximate perihelion distance of ~250 AU. Using an analytic model for secular interactions between Planet Nine and the remaining giant planets, here we show that a planet with similar parameters can naturally generate the observed obliquity as well as the specific pole position of the sun's spin axis, from a nearly aligned initial state. Thus, Planet Nine offers a testable explanation for the otherwise mysterious spin-orbit misalignment of the solar system.

Is There a Planet Nine *AND* Ten?!

Finding Planet Nine: apsidal anti-alignment Monte Carlo results

Authors:

de la Fuente Marcos et al

Abstract:

The distribution of the orbital elements of the known extreme trans-Neptunian objects or ETNOs has been found to be statistically incompatible with that of an unperturbed asteroid population following heliocentric or, better, barycentric orbits. Such trends, if confirmed by future discoveries of ETNOs, strongly suggest that one or more massive perturbers could be located well beyond Pluto. Within the trans-Plutonian planets paradigm, the Planet Nine hypothesis has received much attention as a robust scenario to explain the observed clustering in physical space of the perihelia of seven ETNOs which also exhibit clustering in orbital pole position. Here, we revisit the subject of clustering in perihelia and poles of the known ETNOs using barycentric orbits, and study the visibility of the latest incarnation of the orbit of Planet Nine applying Monte Carlo techniques and focusing on the effects of the apsidal anti-alignment constraint. We provide visibility maps indicating the most likely location of this putative planet if it is near aphelion. We also show that the available data suggest that at least two massive perturbers are present beyond Pluto.

More Evidence for Planet Nine in Trans Neptunian Objects

In the race towards the discovery of a ninth planet in our solar system, scientists from around the world strive to calculate its orbit using the tracks left by the small bodies that move well beyond Neptune. Now, astronomers from Spain and Cambridge University have confirmed, with new calculations, that the orbits of the six extreme trans-Neptunian objects that served as a reference to announce the existence of Planet Nine are not as stable as it was thought.

At the beginning of this year, the astronomers K. Batygin and M. Brown from the California Institute of Technology (Caltech, USA) announced that they had found evidence of the existence of a giant planet with a mass ten times larger than Earth's in the confines of the Solar System. Moving in an unusually elongated orbit, the mysterious planet will take between 10,000 and 20,000 years to complete one revolution around the Sun.

In order to arrive at this conclusion, Batygin and Brown run computer simulations with input data based on the orbits of six extreme trans-Neptunian objects (ETNOs). Specifically, these ETNOs are: Sedna, 2012 VP113, 2004 VN112, 2007 TG422, 2013 RF98 and 2010 GB174.

Now, however, brothers Carlos and Raúl de la Fuente Marcos, two freelance Spanish astronomers, together with scientist Sverre J. Aarseth from the Institute of Astronomy of the University of Cambridge (United Kingdom), have considered the question the other way around: How would the orbits of these six ETNOs evolve if a Planet Nine such as the one proposed by K. Batygin and M. Brown really did exist? The answer to this important question has been published in the journal Monthly Notices of the Royal Astronomical Society (MNRAS).

link.

A Ninth Planet Would Produce a Distinctly Different Distant Kuiper Belt

A Ninth Planet Would Produce a Distinctly Different Distant Kuiper Belt

Authors:

Lawler et al

Abstract:

The orbital element distribution of trans-Neptunian objects (TNOs) with large pericenters has been suggested to be influenced by the presence of an undetected, large planet at 200 or more AU from the Sun. We perform 4 Gyr N-body simulations with the currently known Solar System planetary architecture, plus a 10 Earth mass planet with similar orbital parameters to those suggested by Batygin and Brown (2016) or Trujillo and Sheppard (2014), and a hundred thousand test particles in an initial planetesimal disk. We find that including a distant superearth-mass ninth planet produces a substantially different orbital distribution for the scattering and detached TNOs, raising the pericenters and inclinations of moderate semimajor axis (50 less than a less than 500 AU) objects. We test whether this signature is detectable via a simulator with the observational characteristics of four precisely characterized TNO surveys. We find that the qualitatively very distinct Solar System models that include a ninth planet are essentially observationally indistinguishable from an outer Solar System produced solely by the four giant planets. We also find that the mass of the Kuiper Belt's current scattering and detached populations is required be 3-10 times larger in the presence of an additional planet. Wide-field, deep surveys targeting inclined high-pericenter objects will be required to distinguish between these different scenarios.

Modified Orbital Parameters for Planet Nine

Dynamical impact of the Planet Nine scenario: N-body experiments

Authors:

de la Fuente Marcos et al

Abstract:

The Planet Nine hypothesis has now enough constraints to deserve further attention in the form of detailed numerical experiments. The results of such studies can help us improve our understanding of the dynamical effects of such a hypothetical object on the extreme trans-Neptunian objects or ETNOs and perhaps provide additional constraints on the orbit of Planet Nine itself. Here, we present the results of direct N-body calculations including the latest data available on the Planet Nine conjecture. The present-day orbits of the six ETNOs originally linked to the hypothesis are evolved backwards in time and into the future under some plausible incarnations of the hypothesis to investigate if the values of several orbital elements, including the argument of perihelion, remain confined to relatively narrow ranges. We find that a nominal Planet Nine can keep the orbits of (90377) Sedna and 2012 VP113 relatively well confined in orbital parameter space for hundreds of Myr, but it may make the orbits of 2004 VN112, 2007 TG422 and 2013 RF98 very unstable on time-scales of dozens of Myr, turning them retrograde and eventually triggering their ejection from the Solar system. Far more stable orbital evolution is found with slightly modified orbits for Planet Nine.

NASA: Cassini has NOT had Orbital Anomalies (sorry, Planet Nine)

NASA is denying reports that its Cassini spacecraft is experiencing “unexplained deviations in its orbit around Saturn,” which some attribute to the gravitational pull of a possible undiscovered planet in our Solar System. “While the proposed planet’s existence may eventually be confirmed by other means, mission navigators have observed no unexplained deviations in the spacecraft’s orbit since its arrival there in 2004,” NASA says.

link.

Planet Nine Might be Smaller and Closer than Brown et al Think

Observational Constraints on Planet Nine: Astrometry of Pluto and Other Trans-Neptunian Objects

Authors:

Holman et al

Abstract:

We use astrometry of Pluto and other TNOs to constrain the sky location, distance, and mass of the possible additional planet (Planet Nine) hypothesized by Batygin and Brown (2016). 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 and Brown (2016) based on the orbital distribution of distant trans-neptunian objects (or by Fienga et al. (2016) 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 (Buie and Folkner 2015), which show a clear trend in declination, 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 declination trend may be due to perturbations from a body, additional to Planet Nine , that is closer to Pluto, but less massive than, Planet Nine .

Comparing the the Different Methods of Redirection Methods for Asteroid Mining

Comparative analysis of redirection methods for asteroid resource exploitation

Authors:

Bazzocchi et al

Abstract:

An in-depth analysis and systematic comparison of asteroid redirection methods is performed within a resource exploitation framework using different assessment mechanisms. Through this framework, mission objectives and constraints are specified for the redirection of an asteroid from a near-Earth orbit to a stable orbit in the Earth-Moon system. The paper provides a detailed investigation of five redirection methods, i.e., ion beam, tugboat, gravity tractor, laser sublimation, and mass ejector, with respect to their capabilities for a redirection mission. A set of mission level criteria are utilized to assess the performance of each redirection method, and the means of assigning attributes to each criterion is discussed in detail. In addition, the uncertainty in physical characteristics of the asteroid population is quantified through the use of Monte Carlo analysis. The Monte Carlo simulation provides insight into the performance robustness of the redirection methods with respect to the targeted asteroid range. Lastly, the attributes for each redirection method are aggregated using three different multicriteria assessment approaches, i.e., the analytical hierarchy process, a utility-based approach, and a fuzzy aggregation mechanism. The results of each assessment approach as well as recommendations for further studies are discussed in detail.

Could Jupiter or Saturn Have Ejected a Fifth Giant Planet?

Could Jupiter or Saturn Have Ejected a Fifth Giant Planet?

Authors:

Cloutier et al

Abstract:

Models of the dynamical evolution of the early solar system following the dispersal of the gaseous protoplanetary disk have been widely successful in reconstructing the current orbital configuration of the giant planets. Statistically, some of the most successful dynamical evolution simulations have initially included a hypothetical fifth giant planet, of ice giant mass, which gets ejected by a gas giant during the early solar system's proposed instability phase. We investigate the likelihood of an ice giant ejection event by either Jupiter or Saturn through constraints imposed by the current orbits of their wide-separation regular satellites Callisto and Iapetus respectively. We show that planetary encounters that are sufficient to eject an ice giant, often provide excessive perturbations to the orbits of Callisto and Iapetus making it difficult to reconcile a planet ejection event with the current orbit of either satellite. Quantitatively, we compute the likelihood of reconciling a regular Jovian satellite orbit with the current orbit of Callisto following an ice giant ejection by Jupiter of ~ 42% and conclude that such a large likelihood supports the hypothesis of a fifth giant planet's existence. A similar calculation for Iapetus reveals that it is much more difficult for Saturn to have ejected an ice giant and reconcile a Kronian satellite orbit with that of Iapetus (likelihood ~ 1%), although uncertainties regarding the formation of Iapetus, on its unusual orbit, complicates the interpretation of this result.

The Ultimate Delta V Map of the Solar System

link.

Wait! There Still MIGHT be Something in the Kuiper Belt

Flipping minor bodies: what comet 96P/Machholz 1 can tell us about the orbital evolution of extreme trans-Neptunian objects and the production of near-Earth objects on retrograde orbits

Authors:

de la Fuente Marcos et al

Abstract:

Nearly all known extreme trans-Neptunian objects (ETNOs) have argument of perihelion close to 0°. An existing observational bias strongly favours the detection of ETNOs with arguments of perihelion close to 0° and 180° yet no objects have been found at 180°. No plausible explanation has been offered so far to account for this unusual pattern. Here, we study the dynamical evolution of comet 96P/Machholz 1, a bizarre near-Earth object (NEO) that may provide the key to explain the puzzling clustering of orbits around argument of perihelion close to 0° recently found for the population of ETNOs. Comet 96P/Machholz 1 is currently locked in a Kozai resonance with Jupiter such that the value of its argument of perihelion is always close to 0° at its shortest possible perihelion (highest eccentricity and lowest inclination) and about 180° near its shortest aphelion (longest perihelion distance, lowest eccentricity and highest inclination). If this object is a dynamical analogue (albeit limited) of the known ETNOs, this implies that massive perturbers must keep them confined in orbital parameter space. Besides, its future dynamical evolution displays orbital flips when its eccentricity is excited to a high value and its orbit turns over by nearly 180°, rolling over its major axis. This unusual behaviour, that is preserved when post-Newtonian terms are included in the numerical integrations, may also help understand the production of NEOs on retrograde orbits.

bad astronomer expresses caution.

The Orbits of the Martian Moons

Martian satellite orbits and ephemerides

Authors:

Jacobson et al

Abstract:

We discuss the general characteristics of the orbits of the Martian satellites, Phobos and Deimos. We provide a concise review of the various descriptions of the orbits by both analytical theories and direct numerical integrations of their equations of motion. After summarizing the observational data used to determine the orbits, we discuss the results of our latest orbits obtained from a least squares fit to the data.

Simulating the Dynamical Evolution of Earth, Moon & Theia

Dynamical Evolution of the Earth-Moon Progenitors - Whence Theia?

Authors:

Quarles et al

Abstract:

We present integrations of a model Solar System with five terrestrial planets (beginning ~30-50 Myr after the formation of primitive Solar System bodies) in order to determine the preferred regions of parameter space leading to a giant impact that resulted in the formation of the Moon. Our results indicate which choices of semimajor axes and eccentricities for Theia (the proto-Moon) at this epoch can produce a late Giant Impact, assuming that Mercury, Venus, and Mars are near the current orbits. We find that the likely semimajor axis of Theia, at the epoch when our simulations begin, depends on the assumed mass ratio of Earth-Moon progenitors (8/1, 4/1, or 1/1). The low eccentricities of the terrestrial planets are most commonly produced when the progenitors have similar semimajor axes at the epoch when our integrations commence. Additionally, we show that mean motion resonances among the terrestrial planets and perturbations from the giant planets can affect the dynamical evolution of the system leading to a late Giant Impact.

Uranus' Cupid is Doomed

Cupid is Doomed: An Analysis of the Stability of the Inner Uranian Satellites

Authors:

French et al

Abstract:

We have explored the stability of the inner Uranian satellites using simulations based on the most recent observational data. We find that, across a wide range of mass assumptions, the system is unstable, resulting in the eventual crossing of orbits and probable subsequent collision of moons. Cupid and Belinda are usually the first satellites to cross orbits, and they do so on a time scale of 10^3-10^7 years. Cressida and Desdemona are generally the next pair to cross, on a time scale of 10^5-10^7 years. We show that the crossing times are highly sensitive to initial conditions and that Cupid's instability is related to its resonant interactions with Belinda. We also show that a previously discovered power law, which relates orbit crossing time to satellite mass, is valid across a wide range of masses. We generalize the power law to handle two unstable orbital pairs with overlapping lifetimes and show that it can be used to extend the time span of studies of orbital stability in a computationally efficient manner. Our results suggest that the current Uranian satellite system is in transition and that the moons will continue to collide and reaccrete for the foreseeable future.

Using Solar Sails to Hover Over Spinning Asteroids

Asteroid body-fixed hovering using nonideal solar sails

Authors:

Zeng et al

Abstract:

Asteroid body-fixed hovering problem using nonideal solar sail models in a compact form with controllable sail area is investigated in this paper. The nonlinear dynamic equations for the hovering problem are constructed for a spherically symmetric asteroid. The feasible region for the body-fixed hovering is solved from the above equations by using a shooting method. The effect of the sail models, including the ideal, optical, parametric and solar photon thrust, on the feasible region is studied through numerical simulations. The influence of the asteroid spinning rate and the sail area-to-mass ratio on the feasible region is discussed in a parametric way. The required sail orientations and their corresponding variable lightness numbers are given for different hovering radii to identify the feasibility of the body-fixed hovering. An attractive mission scenario is introduced to enhance the advantage of the solar sail hovering mission.

Do 2012 VP113 and Other Sedna-like Kuiper Belt Bodies' Orbits Suggest *TWO* Trans-Plutonian Planets Exist?!

Extreme trans-Neptunian objects and the Kozai mechanism: signaling the presence of trans-Plutonian planets?

Authors:

la Fuente Marcos et al

Abstract:

The existence of an outer planet beyond Pluto has been a matter of debate for decades and the recent discovery of 2012 VP113 has just revived the interest for this controversial topic. This Sedna-like object has the most distant perihelion of any known minor planet and the value of its argument of perihelion is close to 0 degrees. This property appears to be shared by almost all known asteroids with semimajor axis greater than 150 au and perihelion greater than 30 au (the extreme trans-Neptunian objects or ETNOs), and this fact has been interpreted as evidence for the existence of a super-Earth at 250 au. In this scenario, a population of stable asteroids may be shepherded by a distant, undiscovered planet larger than the Earth that keeps the value of their argument of perihelion librating around 0 degrees as a result of the Kozai mechanism. Here, we study the visibility of these ETNOs and confirm that the observed excess of objects reaching perihelion near the ascending node cannot be explained in terms of any observational biases. This excess must be a true feature of this population and its possible origin is explored in the framework of the Kozai effect. The analysis of several possible scenarios strongly suggest that at least two trans-Plutonian planets must exist.

Understanding Uranus' Transient Trojans (? Co-orbitals at least)

Comparative orbital evolution of transient Uranian co-orbitals: exploring the role of ephemeral multibody mean motion resonances

Authors:

de la Fuente Marcos

Abstract:

Uranus has three known co-orbitals: 83982 Crantor (2002 GO9), 2010 EU65 and 2011 QF99. All of them were captured in their current resonant state relatively recently. Here, we perform a comparative analysis of the orbital evolution of these transient co-orbitals to understand better how they got captured in the first place and what makes them dynamically unstable. We also look for additional temporary Uranian co-orbital candidates among known objects. Our N-body simulations show that the long-term stability of 2011 QF99 is controlled by Jupiter and Neptune; it briefly enters the 1:7 mean motion resonance with Jupiter and the 2:1 with Neptune before becoming a Trojan and prior to leaving its tadpole orbit. During these ephemeral two-body mean motion resonance episodes, apsidal corotation resonances are also observed. For known co-orbitals, Saturn is the current source of the main destabilizing force but this is not enough to eject a minor body from the 1:1 commensurability with Uranus. These objects must enter mean motion resonances with Jupiter and Neptune in order to be captured or become passing Centaurs. Asteroid 2010 EU65, a probable visitor from the Oort cloud, may have been stable for several Myr due to its comparatively low eccentricity. Additionally, we propose 2002 VG131 as the first transient quasi-satellite candidate of Uranus. Asteroid 1999 HD12 may signal the edge of Uranus’ co-orbital region. Transient Uranian co-orbitals are often submitted to complex multibody ephemeral mean motion resonances that trigger the switching between resonant co-orbital states, making them dynamically unstable. In addition, we show that the orbital properties and discovery circumstances of known objects can be used to outline a practical strategy by which additional Uranus’ co-orbitals may be found.