This paper is devoted to the stability of possible, inclined Trojan planets in double star system... more This paper is devoted to the stability of possible, inclined Trojan planets in double star systems. We investigated the size of the stable region around the Lagrangian point L4 by using numerical integrations, depending on the mass ratio and the eccentricity of the secondary star. The dynamical model we used was the spatial elliptic restricted three body problem. We created a catalogue of initial conditions where a Trojan planet can be stable. These results could be useful for future observations and help to detect such objects.
NEOShield is a consortium of 13 research institutes, universities and industrial partners from 6 ... more NEOShield is a consortium of 13 research institutes, universities and industrial partners from 6 countries. The aim of the project is to explore mitigation options in the event that a NEO is found to be on a potential collision course with Earth, and to pave the way for demonstration missions to test proposed mitigation techniques. Finding an accessible and appropriate target NEO for a demonstration mission is an important aspect of mission design. Targets for NEOShield and other potential missions require both a firm orbit and physical characterization. With > 900 NEOs discovered per year, it is important to assess the state of our knowledge of potential mission targets, and what future possibilities exist for refining that knowledge. We have created a web-based tool to to aid the provision of NEO mission targets, either for orbit improvement or for physical studies. It currently resides at http://star.pst.qub.ac.uk/~af/lowdv_neos/. Its primary purposes are to act as initial gui...
Proceedings of the International Astronomical Union, 2014
Close encounters of Near Earth Objects (NEOs) with large asteroids are a possible source of syste... more Close encounters of Near Earth Objects (NEOs) with large asteroids are a possible source of systematic errors in trajectory propagations and asteroid mitigation. It is, thus, necessary to identify those large asteroids that have to be considered as perturbers in NEO orbit modeling. Using the Standard Dynamical Model we searched for encounters between the 1649 numbered Near Earth Asteroids (NEAs) and 2191 large asteroids having sizes greater than 20 km. Investigating the 21 st century A.D. we have found 791 close encounters with 195 different large asteroids that lead to a substantial scattering of NEOs.
Abstract: The recent past has seen robots develop into autonomous artificial agents capable of ex... more Abstract: The recent past has seen robots develop into autonomous artificial agents capable of executing complex tasks. In the near future, robots will likely develop the ability to adapt and learn from their surroundings. Robots have reliance, accuracy, and can operate in hostile environments-all attributes well suited for space exploration. Robots also reduce mission costs, increase design flexibility, and maximize data production. On the other hand, when faced with new scenarios and unexpected events, robots pale in comparison with ...
Context. More than 60 planets have been discovered so far in systems that harbour two stars, some... more Context. More than 60 planets have been discovered so far in systems that harbour two stars, some of which have binary semi-major axes as small as 20 au. It is well known that the formation of planets in such systems is strongly influenced by the stellar components, since the protoplanetary disc and the particles within are exposed to the gravitational influence of the binary. However, the question on how self-gravitating protoplanetary bodies affect the evolution of a radiative, circumprimary disc is still open. Aims. We present our 2D hydrodynamical GPU-CPU code and study the interaction of several thousands of self-gravitating particles with a viscous and radiative circumprimary disc within a binary star system. To our knowledge this program is the only one at the moment that is capable to handle this many particles and to calculate their influence on each other and on the disc. Methods. We performed hydrodynamical simulations of a circumstellar disc assuming the binary system to be coplanar. Our gridbased staggered mesh code relies on ideas from ZEUS-2D, where we implemented the FARGO algorithm and an additional energy equation for the radiative cooling according to opacity tables. To treat particle motion we used a parallelised version of the precise Bulirsch -Stoer algorithm. Four models in total where computed taking into account (i) only N-body interaction, (ii) N-body and disc interaction, (iii) the influence of computational parameters (especially smoothing) on N-body interaction, and (iv) the influence of a quiet low-eccentricity disc while running model (ii). The impact velocities where measured at two different time intervals and were compared. Results. We show that the combination of disc-and N-body self-gravity can have a significant influence on the orbit evolution of roughly Moon sized protoplanets. Conclusions. Not only gas drag can alter the orbit of particles, but the gravitational influence of the disc can accomplish this as well. The results depend strongly on the state of the disc (i.e. quiet or dynamically evolving) -according to encounter-probability distributions, planet formation can be strongly altered if there is a dynamically evolving gas disc -and also on the smoothing parameter.
Proceedings of the International Astronomical Union, 2010
Discoveries of extrasolar planets in tight binaries are of great scientific value since these sys... more Discoveries of extrasolar planets in tight binaries are of great scientific value since these systems can be used to gain new insights in planetary development processes. Gamma Cephei, one of the most thoroughly investigated double star systems is hosting a Jovian planet at a distance of about 2 AU from its primary, a 1.4 solar-mass K1 III-IV star . We comprise aspects of dynamical stability, disc heating processes and different giant planet (GP) formation scenarios in order to gain a better understanding of the open questions that remain in explaining the formation of gamma Cephei b.
Proceedings of the International Astronomical Union, 2012
ABSTRACT The discovery of more and more extra-solar planets in and around binary star systems cau... more ABSTRACT The discovery of more and more extra-solar planets in and around binary star systems cause questions concerning the determination of the classical habitable zone (HZ). We present calculations of the radiative and gravitational perturbations of two stars on a terrestrial planet moving in the HZ in different binary - planet configurations. Two types of planetary motion will be considered, i.e. S-type motion (or circumprimary motion) where the planet orbits one star only and P-type (or circumbinary motion) where the binary revolves inside the planet's orbit. It was found that the HZ in S-type configurations tend to be gravitationally dominated, the radiative input due to the second star is negligible compared to its dynamical influence causing secular changes in the eccentricity of the planets. This alters the amount of incident radiation significantly. In P-type configurations the radiation estimates can be determined on shorter time-scales. The radiation amplitude depends on the eccentricity of the binary in both configurations. Finally we present time independent analytical estimates about the habitability of a terrestrial planet in the HZ of a binary star system as shown by Eggl et al.(2012). This work was financed by the Austrian Science Fonds (FWF) P22603-N16 and AS11608-N16 and S.Eggl was financed by the University of Vienna (Forschungsstipendium 2012). Ref.: Eggl, S., Pilat-Lohinger, E., Gerogakarakos, N., Gyergyovits, M. and Funk, B., "Habitable Zones in S-Type Binary Star Systems", ApJ, submitted.
Given the considerable percentage of stars that are members of binaries or stellar multiples in t... more Given the considerable percentage of stars that are members of binaries or stellar multiples in the Solar neighborhood, it is expected that many of these binaries host planets, possibly even habitable ones. The discovery of a terrestrial planet in the alpha Centauri system supports this notion. Due to the potentially strong gravitational interaction that an Earth-like planet may experience in such systems, classical approaches to determining habitable zones, especially in close S-Type binary systems, can be rather inaccurate. Recent progress in this field, however, allows to identify regions around the star permitting permanent habitability. While the discovery of alpha Cen Bb has shown that terrestrial planets can be detected in solar-type binary stars using current observational facilities, it remains to be shown whether this is also the case for Earth analogues in habitable zones. We provide analytical expressions for the maximum and RMS values of radial velocity and astrometric signals, as well as transit probabilities of terrestrial planets in such systems, showing that the dynamical interaction of the second star with the planet may indeed facilitate the planets detection. As an example, we discuss the detectability of additional Earth-like planets in the averaged, extended, and permanent habitable zones around both stars of the alpha Centauri system.
Locating planets in Habitable Zones (HZs) around other stars is a growing field in contemporary a... more Locating planets in Habitable Zones (HZs) around other stars is a growing field in contemporary astronomy. Since a large percentage of all G-M stars in the solar neighbourhood are expected to be part of binary or multiple stellar systems, investigations of whether habitable planets are likely to be discovered in such environments are of prime interest to the scientific community. As current exoplanet statistics predicts that the chances are higher to find new worlds in systems that are already known to have planets, we examine four known extrasolar planetary systems in tight binaries in order to determine their capacity to host additional habitable terrestrial planets. Those systems are Gliese 86, γ Cephei, HD 41004 and HD 196885. In the case of γ Cephei, our results suggest that only the M dwarf companion could host additional potentially habitable worlds. Neither could we identify stable, potentially habitable regions around HD 196885 A. HD 196885 B can be considered a slightly mo...
We study the problem of efficient integration of variational equations in multi-dimensional Hamil... more We study the problem of efficient integration of variational equations in multi-dimensional Hamiltonian systems. For this purpose, we consider a Runge-Kutta-type integrator, a Taylor series expansion method and the so-called `Tangent Map' (TM) technique based on symplectic integration schemes, and apply them to the Fermi-Pasta-Ulam $\beta$ (FPU-$\beta$) lattice of $N$ nonlinearly coupled oscillators, with $N$ ranging from 4 to 20.
Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the habitable z... more Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the habitable zone (HZ) of Sun-like stars. In the near future astronomers will try to find such an "exo-Earth" orbiting within the HZ of other stars having various ground-based and space missions (e.g., CoRoT, Kepler, Gaia) at their disposal. It is well known, that the evolution of a biosphere is a process covering stellar timescales, therefore one of the basic requirements for habitability is the long-term orbital stability of planets in the HZ. This investigation tackles the dynamical stability of potential additional terrestrial planets in nearby (within 30 pc) extrasolar planetary systems. Global studies do exist, that provide stability maps for systems consisting of a star, a gas giant and mass-less test-planets, e.g., the so-called "Exocatalogue" (see http://astro.elte.hu/exocatalogue/). Additionally we provide the tool ``ExoStab'' (see http://www.univie.ac.at/adg/exos...
ABSTRACT Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the ha... more ABSTRACT Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the habitable zone (HZ) of Sun-like stars. In the near future astronomers will try to find such an "exo-Earth" orbiting within the HZ of other stars having various ground-based and space missions (e.g., CoRoT, Kepler, Gaia) at their disposal. It is well known, that the evolution of a biosphere is a process covering stellar timescales, therefore one of the basic requirements for habitability is the long-term orbital stability of planets in the HZ. This investigation tackles the dynamical stability of potential additional terrestrial planets in nearby (within 30 pc) extrasolar planetary systems. Global studies do exist, that provide stability maps for systems consisting of a star, a gas giant and mass-less test-planets, e.g., the so-called "Exocatalogue" (see http://astro.elte.hu/exocatalogue/). Additionally we provide the tool ``ExoStab'' (see http://www.univie.ac.at/adg/exostab/), which allows a more interactive application of the Exocatalogue data. Utilities like these are used to verify the long-term stability of an additional low-mass planet moving in a particular single-star single-planet system. A comparison of the results of numerical simulations including also massive test-planets with the Exocatalogue will be shown. Since some orbital elements, like e.g., the orbital eccentricities, the mass of the gas giant or its semi-major axis are afflicted with errors, we will also perform a parameter study, to ensure the validity of our results.
The Vesta family is the largest asteroidal family known in the inner main belt, and it is believe... more The Vesta family is the largest asteroidal family known in the inner main belt, and it is believed to be a source of HED meteorites. We study its long-term evolution and investigate close encounters with Ceres, Vesta, and terrestrial planets.
Proceedings of the International Astronomical Union, 2014
Determining planetary habitability is a complex matter, as the interplay between a planet's physi... more Determining planetary habitability is a complex matter, as the interplay between a planet's physical and atmospheric properties with stellar insolation has to be studied in a self consistent manner. Standardized atmospheric models for Earth-like planets exist and are commonly accepted as a reference for estimates of Habitable Zones. In order to define Habitable Zone boundaries, circular orbital configurations around main sequence stars are generally assumed. In gravitationally interacting multibody systems, such as double stars, however, planetary orbits are forcibly becoming non circular with time. Especially in binary star systems even relatively small changes in a planet's orbit can have a large impact on habitability. Hence, we argue that a minimum model for calculating Habitable Zones in binary star systems has to include dynamical interactions.
ABSTRACT So far, multiple stellar systems harbor more than 130 extra solar planets. Dynamical sim... more ABSTRACT So far, multiple stellar systems harbor more than 130 extra solar planets. Dynamical simulations show that the outcome of planetary formation process can lead to various planetary architecture (i.e. location, size, mass and water content) when the star system is single or double. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (hereafter HZ). In this study, we make a comparison of several binary star systems and their efficiency to move icy asteroids from beyond the snow-line into orbits crossing the HZ. We modeled a belt of 10000 asteroids (remnants from the late phase of planetary formation process) beyond the snow-line. The planetesimals are placed randomly around the primary star and move under the gravitational influence of the two stars and a gas giant. As the planetesimals do not interact with each other, we divided the belt into 100 subrings which were separately integrated. In this statistical study, several double star configurations with a G-type star as primary are investigated. Our results show that small bodies also participate in bearing a non-negligible amount of water to the HZ. The proximity of a companion moving on an eccentric orbit increases the flux of asteroids to the HZ, which could result into a more efficient water transport on a short timescale, causing a heavy bombardment. A comparison with similar simulations in a single star system indicates also a more efficient flux of asteroids in binary stars.
This paper is devoted to the stability of possible, inclined Trojan planets in double star system... more This paper is devoted to the stability of possible, inclined Trojan planets in double star systems. We investigated the size of the stable region around the Lagrangian point L4 by using numerical integrations, depending on the mass ratio and the eccentricity of the secondary star. The dynamical model we used was the spatial elliptic restricted three body problem. We created a catalogue of initial conditions where a Trojan planet can be stable. These results could be useful for future observations and help to detect such objects.
NEOShield is a consortium of 13 research institutes, universities and industrial partners from 6 ... more NEOShield is a consortium of 13 research institutes, universities and industrial partners from 6 countries. The aim of the project is to explore mitigation options in the event that a NEO is found to be on a potential collision course with Earth, and to pave the way for demonstration missions to test proposed mitigation techniques. Finding an accessible and appropriate target NEO for a demonstration mission is an important aspect of mission design. Targets for NEOShield and other potential missions require both a firm orbit and physical characterization. With > 900 NEOs discovered per year, it is important to assess the state of our knowledge of potential mission targets, and what future possibilities exist for refining that knowledge. We have created a web-based tool to to aid the provision of NEO mission targets, either for orbit improvement or for physical studies. It currently resides at http://star.pst.qub.ac.uk/~af/lowdv_neos/. Its primary purposes are to act as initial gui...
Proceedings of the International Astronomical Union, 2014
Close encounters of Near Earth Objects (NEOs) with large asteroids are a possible source of syste... more Close encounters of Near Earth Objects (NEOs) with large asteroids are a possible source of systematic errors in trajectory propagations and asteroid mitigation. It is, thus, necessary to identify those large asteroids that have to be considered as perturbers in NEO orbit modeling. Using the Standard Dynamical Model we searched for encounters between the 1649 numbered Near Earth Asteroids (NEAs) and 2191 large asteroids having sizes greater than 20 km. Investigating the 21 st century A.D. we have found 791 close encounters with 195 different large asteroids that lead to a substantial scattering of NEOs.
Abstract: The recent past has seen robots develop into autonomous artificial agents capable of ex... more Abstract: The recent past has seen robots develop into autonomous artificial agents capable of executing complex tasks. In the near future, robots will likely develop the ability to adapt and learn from their surroundings. Robots have reliance, accuracy, and can operate in hostile environments-all attributes well suited for space exploration. Robots also reduce mission costs, increase design flexibility, and maximize data production. On the other hand, when faced with new scenarios and unexpected events, robots pale in comparison with ...
Context. More than 60 planets have been discovered so far in systems that harbour two stars, some... more Context. More than 60 planets have been discovered so far in systems that harbour two stars, some of which have binary semi-major axes as small as 20 au. It is well known that the formation of planets in such systems is strongly influenced by the stellar components, since the protoplanetary disc and the particles within are exposed to the gravitational influence of the binary. However, the question on how self-gravitating protoplanetary bodies affect the evolution of a radiative, circumprimary disc is still open. Aims. We present our 2D hydrodynamical GPU-CPU code and study the interaction of several thousands of self-gravitating particles with a viscous and radiative circumprimary disc within a binary star system. To our knowledge this program is the only one at the moment that is capable to handle this many particles and to calculate their influence on each other and on the disc. Methods. We performed hydrodynamical simulations of a circumstellar disc assuming the binary system to be coplanar. Our gridbased staggered mesh code relies on ideas from ZEUS-2D, where we implemented the FARGO algorithm and an additional energy equation for the radiative cooling according to opacity tables. To treat particle motion we used a parallelised version of the precise Bulirsch -Stoer algorithm. Four models in total where computed taking into account (i) only N-body interaction, (ii) N-body and disc interaction, (iii) the influence of computational parameters (especially smoothing) on N-body interaction, and (iv) the influence of a quiet low-eccentricity disc while running model (ii). The impact velocities where measured at two different time intervals and were compared. Results. We show that the combination of disc-and N-body self-gravity can have a significant influence on the orbit evolution of roughly Moon sized protoplanets. Conclusions. Not only gas drag can alter the orbit of particles, but the gravitational influence of the disc can accomplish this as well. The results depend strongly on the state of the disc (i.e. quiet or dynamically evolving) -according to encounter-probability distributions, planet formation can be strongly altered if there is a dynamically evolving gas disc -and also on the smoothing parameter.
Proceedings of the International Astronomical Union, 2010
Discoveries of extrasolar planets in tight binaries are of great scientific value since these sys... more Discoveries of extrasolar planets in tight binaries are of great scientific value since these systems can be used to gain new insights in planetary development processes. Gamma Cephei, one of the most thoroughly investigated double star systems is hosting a Jovian planet at a distance of about 2 AU from its primary, a 1.4 solar-mass K1 III-IV star . We comprise aspects of dynamical stability, disc heating processes and different giant planet (GP) formation scenarios in order to gain a better understanding of the open questions that remain in explaining the formation of gamma Cephei b.
Proceedings of the International Astronomical Union, 2012
ABSTRACT The discovery of more and more extra-solar planets in and around binary star systems cau... more ABSTRACT The discovery of more and more extra-solar planets in and around binary star systems cause questions concerning the determination of the classical habitable zone (HZ). We present calculations of the radiative and gravitational perturbations of two stars on a terrestrial planet moving in the HZ in different binary - planet configurations. Two types of planetary motion will be considered, i.e. S-type motion (or circumprimary motion) where the planet orbits one star only and P-type (or circumbinary motion) where the binary revolves inside the planet's orbit. It was found that the HZ in S-type configurations tend to be gravitationally dominated, the radiative input due to the second star is negligible compared to its dynamical influence causing secular changes in the eccentricity of the planets. This alters the amount of incident radiation significantly. In P-type configurations the radiation estimates can be determined on shorter time-scales. The radiation amplitude depends on the eccentricity of the binary in both configurations. Finally we present time independent analytical estimates about the habitability of a terrestrial planet in the HZ of a binary star system as shown by Eggl et al.(2012). This work was financed by the Austrian Science Fonds (FWF) P22603-N16 and AS11608-N16 and S.Eggl was financed by the University of Vienna (Forschungsstipendium 2012). Ref.: Eggl, S., Pilat-Lohinger, E., Gerogakarakos, N., Gyergyovits, M. and Funk, B., "Habitable Zones in S-Type Binary Star Systems", ApJ, submitted.
Given the considerable percentage of stars that are members of binaries or stellar multiples in t... more Given the considerable percentage of stars that are members of binaries or stellar multiples in the Solar neighborhood, it is expected that many of these binaries host planets, possibly even habitable ones. The discovery of a terrestrial planet in the alpha Centauri system supports this notion. Due to the potentially strong gravitational interaction that an Earth-like planet may experience in such systems, classical approaches to determining habitable zones, especially in close S-Type binary systems, can be rather inaccurate. Recent progress in this field, however, allows to identify regions around the star permitting permanent habitability. While the discovery of alpha Cen Bb has shown that terrestrial planets can be detected in solar-type binary stars using current observational facilities, it remains to be shown whether this is also the case for Earth analogues in habitable zones. We provide analytical expressions for the maximum and RMS values of radial velocity and astrometric signals, as well as transit probabilities of terrestrial planets in such systems, showing that the dynamical interaction of the second star with the planet may indeed facilitate the planets detection. As an example, we discuss the detectability of additional Earth-like planets in the averaged, extended, and permanent habitable zones around both stars of the alpha Centauri system.
Locating planets in Habitable Zones (HZs) around other stars is a growing field in contemporary a... more Locating planets in Habitable Zones (HZs) around other stars is a growing field in contemporary astronomy. Since a large percentage of all G-M stars in the solar neighbourhood are expected to be part of binary or multiple stellar systems, investigations of whether habitable planets are likely to be discovered in such environments are of prime interest to the scientific community. As current exoplanet statistics predicts that the chances are higher to find new worlds in systems that are already known to have planets, we examine four known extrasolar planetary systems in tight binaries in order to determine their capacity to host additional habitable terrestrial planets. Those systems are Gliese 86, γ Cephei, HD 41004 and HD 196885. In the case of γ Cephei, our results suggest that only the M dwarf companion could host additional potentially habitable worlds. Neither could we identify stable, potentially habitable regions around HD 196885 A. HD 196885 B can be considered a slightly mo...
We study the problem of efficient integration of variational equations in multi-dimensional Hamil... more We study the problem of efficient integration of variational equations in multi-dimensional Hamiltonian systems. For this purpose, we consider a Runge-Kutta-type integrator, a Taylor series expansion method and the so-called `Tangent Map' (TM) technique based on symplectic integration schemes, and apply them to the Fermi-Pasta-Ulam $\beta$ (FPU-$\beta$) lattice of $N$ nonlinearly coupled oscillators, with $N$ ranging from 4 to 20.
Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the habitable z... more Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the habitable zone (HZ) of Sun-like stars. In the near future astronomers will try to find such an "exo-Earth" orbiting within the HZ of other stars having various ground-based and space missions (e.g., CoRoT, Kepler, Gaia) at their disposal. It is well known, that the evolution of a biosphere is a process covering stellar timescales, therefore one of the basic requirements for habitability is the long-term orbital stability of planets in the HZ. This investigation tackles the dynamical stability of potential additional terrestrial planets in nearby (within 30 pc) extrasolar planetary systems. Global studies do exist, that provide stability maps for systems consisting of a star, a gas giant and mass-less test-planets, e.g., the so-called "Exocatalogue" (see http://astro.elte.hu/exocatalogue/). Additionally we provide the tool ``ExoStab'' (see http://www.univie.ac.at/adg/exos...
ABSTRACT Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the ha... more ABSTRACT Discoveries of super-Earths raise our hopes to find terrestrial planets moving in the habitable zone (HZ) of Sun-like stars. In the near future astronomers will try to find such an "exo-Earth" orbiting within the HZ of other stars having various ground-based and space missions (e.g., CoRoT, Kepler, Gaia) at their disposal. It is well known, that the evolution of a biosphere is a process covering stellar timescales, therefore one of the basic requirements for habitability is the long-term orbital stability of planets in the HZ. This investigation tackles the dynamical stability of potential additional terrestrial planets in nearby (within 30 pc) extrasolar planetary systems. Global studies do exist, that provide stability maps for systems consisting of a star, a gas giant and mass-less test-planets, e.g., the so-called "Exocatalogue" (see http://astro.elte.hu/exocatalogue/). Additionally we provide the tool ``ExoStab'' (see http://www.univie.ac.at/adg/exostab/), which allows a more interactive application of the Exocatalogue data. Utilities like these are used to verify the long-term stability of an additional low-mass planet moving in a particular single-star single-planet system. A comparison of the results of numerical simulations including also massive test-planets with the Exocatalogue will be shown. Since some orbital elements, like e.g., the orbital eccentricities, the mass of the gas giant or its semi-major axis are afflicted with errors, we will also perform a parameter study, to ensure the validity of our results.
The Vesta family is the largest asteroidal family known in the inner main belt, and it is believe... more The Vesta family is the largest asteroidal family known in the inner main belt, and it is believed to be a source of HED meteorites. We study its long-term evolution and investigate close encounters with Ceres, Vesta, and terrestrial planets.
Proceedings of the International Astronomical Union, 2014
Determining planetary habitability is a complex matter, as the interplay between a planet's physi... more Determining planetary habitability is a complex matter, as the interplay between a planet's physical and atmospheric properties with stellar insolation has to be studied in a self consistent manner. Standardized atmospheric models for Earth-like planets exist and are commonly accepted as a reference for estimates of Habitable Zones. In order to define Habitable Zone boundaries, circular orbital configurations around main sequence stars are generally assumed. In gravitationally interacting multibody systems, such as double stars, however, planetary orbits are forcibly becoming non circular with time. Especially in binary star systems even relatively small changes in a planet's orbit can have a large impact on habitability. Hence, we argue that a minimum model for calculating Habitable Zones in binary star systems has to include dynamical interactions.
ABSTRACT So far, multiple stellar systems harbor more than 130 extra solar planets. Dynamical sim... more ABSTRACT So far, multiple stellar systems harbor more than 130 extra solar planets. Dynamical simulations show that the outcome of planetary formation process can lead to various planetary architecture (i.e. location, size, mass and water content) when the star system is single or double. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (hereafter HZ). In this study, we make a comparison of several binary star systems and their efficiency to move icy asteroids from beyond the snow-line into orbits crossing the HZ. We modeled a belt of 10000 asteroids (remnants from the late phase of planetary formation process) beyond the snow-line. The planetesimals are placed randomly around the primary star and move under the gravitational influence of the two stars and a gas giant. As the planetesimals do not interact with each other, we divided the belt into 100 subrings which were separately integrated. In this statistical study, several double star configurations with a G-type star as primary are investigated. Our results show that small bodies also participate in bearing a non-negligible amount of water to the HZ. The proximity of a companion moving on an eccentric orbit increases the flux of asteroids to the HZ, which could result into a more efficient water transport on a short timescale, causing a heavy bombardment. A comparison with similar simulations in a single star system indicates also a more efficient flux of asteroids in binary stars.
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Papers by Siegfried Eggl