TY - JOUR AU - Beauge, C AU - Sándor, Zsolt AU - Érdi, Bálint AU - Süli, Áron TI - Co-orbital terrestrial planets in exoplanetary systems: a formation scenario JF - ASTRONOMY & ASTROPHYSICS J2 - ASTRON ASTROPHYS VL - 463 PY - 2007 IS - 1 SP - 359 EP - 367 PG - 9 SN - 0004-6361 DO - 10.1051/0004-6361:20066582 UR - https://m2.mtmt.hu/api/publication/1457218 ID - 1457218 N1 - Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, (X5000BGR) Córdoba, Argentina Department of Astronomy, Loránd Eötvös University, Pazmany Peter setany. 1/A, 1117 Budapest, Hungary Cited By :54 Export Date: 15 February 2023 CODEN: AAEJA Correspondence Address: Beaugé, C.; Observatorio Astronómico, Laprida 854, (X5000BGR) Córdoba, Argentina; email: beauge@oac.uncor.edu AB - Aims. We study the formation of a hypothetical terrestrial-type body in the equilateral Lagrange points of a giant extrasolar planet. Starting from a swarm of planetesimals in stable tadpole orbits, we simulate its dynamical and collisional evolution under a wide range of different initial conditions and masses for both the Trojan population and its planetary companion. We also analyze the effects of gas drag from the interaction of the planetesimals with the nebular disk. Methods. The formation process is simulated with an N-body code that considers full gravitational interactions between the planetesimals and the giant planet. Gas interaction is modeled with Stokes and Epstein drags, where the drag coefficients are chosen following the results of full hydrodynamic simulations performed with the 2D public hydro-code FARGO. Results. In both gas-free and gas-rich scenarios, we have been able to obtain a single final terrestrial-type body in a stable tadpole orbit around one of the triangular Lagrange points of the system. However, due to gravitational instabilities within the swarm, the accretional process is not very efficient and the mass of the final planet never seems to exceed similar to 0.6 Earth masses, even when the total mass of the swarm is five times this value. Finally, we also included an orbital decay of the giant planet due to a type II migration. Although the accretional process shows evidence of a lower efficiency, a small terrestrial planet is still able to form, and follows the giant planet towards the habitable zone of the hosting star. LA - English DB - MTMT ER - TY - JOUR AU - Érdi, Bálint AU - Nagy, Imre AU - Sándor, Zsolt AU - Süli, Áron AU - Fröhlich, Georgina TI - Secondary resonances of co-orbital motions JF - MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY J2 - MON NOT R ASTRON SOC VL - 381 PY - 2007 IS - 1 SP - 33 EP - 40 PG - 8 SN - 0035-8711 DO - 10.1111/j.1365-2966.2007.12228.x UR - https://m2.mtmt.hu/api/publication/1457216 ID - 1457216 AB - The size distribution of the stability region around the Lagrangian point L-4 is investigated in the elliptic restricted three-body problem as the function of the mass parameter and the orbital eccentricity of the primaries. It is shown that there are minimum zones in the size distribution of the stability regions, and these zones are connected with the secondary resonances between the frequencies of librational motions around L-4. The results can be applied to hypothetical Trojan planets for predicting values of the mass parameter and the eccentricity for which such objects can be expected or their existence is less probable. LA - English DB - MTMT ER - TY - JOUR AU - Schwarz, Richárd AU - Dvorak, R AU - Süli, Áron AU - Érdi, Bálint TI - Survey of the stability region of hypothetical habitable Trojan planets JF - ASTRONOMY & ASTROPHYSICS J2 - ASTRON ASTROPHYS VL - 474 PY - 2007 IS - 3 SP - 1023 EP - 1029 PG - 7 SN - 0004-6361 DO - 10.1051/0004-6361:20077994 UR - https://m2.mtmt.hu/api/publication/1457212 ID - 1457212 N1 - Institute for Astronomy, University of Vienna, Türkenschanzstr. 17, 1180 Wien, Austria Department of Astronomy, Eötvös University, Pazmany Peter setany 1/A, Budapest 1117, Hungary Cited By :36 Export Date: 13 September 2023 CODEN: AAEJA Correspondence Address: Schwarz, R.; Institute for Astronomy, Türkenschanzstr. 17, 1180 Wien, Austria; email: schwarz@astro.univie.ac.at AB - Aims. In this work we study the dynamical possibility in extrasolar planetary systems that a terrestrial planet can exist in 1:1 mean motion resonance with a Jovian-like planet. We compiled a catalogue of hypothetical habitable Trojan planets, to be able to make a stability forecast for further extrasolar planetary systems discovered in the future. When speaking of habitability we also took the influence of the spectral type of the central star into account. Methods. We integrated some 106 orbits of fictitious Trojans around the Lagrangian points for up to 107 orbital periods of the primary bodies and checked the stability of the orbital elements and their chaoticity with the aid of the Lyapunov characteristic indicator and maximum eccentricity. The computations were carried out using the dynamical model of the elliptic, restricted three-body problem that consists of a central star, a gas giant moving in the habitable zone, and a hypothetical (massless) terrestrial planet. Results. Our investigations have shown that 7 exoplanetary systems can harbour habitable Trojan planets with stable orbits (HD93083, HD17051, HD28185, HD27442, HD188015, HD99109, and HD221287, which is a recently discovered system). The comparison of the investigated systems with our catalogue showed matching results, so that we can use the catalogue in practice. LA - English DB - MTMT ER - TY - JOUR AU - Schwarz, Richárd AU - Dvorak, R AU - Lohinger, EP AU - Süli, Áron AU - Érdi, Bálint TI - Trojan planets in HD 108874? JF - ASTRONOMY & ASTROPHYSICS J2 - ASTRON ASTROPHYS VL - 462 PY - 2007 IS - 3 SP - 1165 EP - 1170 PG - 6 SN - 0004-6361 DO - 10.1051/0004-6361:20066284 UR - https://m2.mtmt.hu/api/publication/1457220 ID - 1457220 AB - Aims: It turned out recently that, in addition to a large planet with a semimajor axis a similar to 1 AU and a low eccentricity (e similar to 0.07), the extrasolar planetary system HD 108874 harbors another massive planet with 2.43 AU < a < 2.93 AU. The inner planet is orbiting the G5 host star in the habitable zone (= HZ); so that we could established stable regions for Earth-like Trojan planets. Methods. We integrated some 105 orbits of fictitious Trojans around the Lagrangian points for up to 107 years and checked the stability of the orbital elements and their chaoticity with the aid of the Fast Lyapunov Indicator. Results. It turns out that this multiplanetary system is the first one where-with the uncertainties in eccentricity and semimajor axes of the outer planet-the existence of Trojan terrestrial planets in stable orbits in the HZ is possible for some combinations of the orbital parameters. LA - English DB - MTMT ER - TY - JOUR AU - Efthymiopoulos, C AU - Sándor, Zsolt TI - Optimized Nekhoroshev stability estimates for the Trojan asteroids with a symplectic mapping model of co-orbital motion JF - MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY J2 - MON NOT R ASTRON SOC VL - 364 PY - 2005 SP - 253 EP - 271 PG - 19 SN - 0035-8711 DO - 10.1111/j.1365-2966.2005.09572.x UR - https://m2.mtmt.hu/api/publication/2794766 ID - 2794766 N1 - Cited By :33 Export Date: 15 February 2023 CODEN: MNRAA Correspondence Address: Efthymiopoulos, C.; Research Centre for Astronomy and Applied Mathematics, Soranou Efessiou 4, GR-11527 Athens, Greece; email: cefthim@cc.uoa.gr AB - This paper reports analytic estimates of the domain of Nekhoroshev stability for the orbits of Jupiter's Trojan asteroids calculated in the space of proper elements (Dp, ep), for a stability time exceeding the age of the Solar system (tstability= 1010 yr). The model used is a family of Hadjidemetriou mappings, for different values of the proper eccentricity ep, that represent the Poincaré sections of co-orbital motion in the Hamiltonian of the planar and circular restricted three-body problem. These explicit mappings are shown to reproduce accurately the dynamics that is implicitly induced by the corresponding Hamiltonian model. Optimal Nekhoroshev estimates are obtained by constructing the Birkhoff normal form for symplectic mappings. Our optimization is based on an `iterated remainder' criterion. The asymptotic behaviour of the Birkhoff series is determined by a precise analysis of the accumulation of small divisors in the series terms at consecutive orders of normalization. About 35 per cent of asteroids from a recent catalogue (AstDys), with proper inclination Ip<= 5°, are shown to be Nekhoroshev-stable over the age of the Solar system. By calculating a resonant Birkhoff normal form, this percentage increases to 48 per cent. LA - English DB - MTMT ER - TY - JOUR AU - Érdi, Bálint AU - Sándor, Zsolt TI - Stability of co-orbital motion in exoplanetary systems JF - CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY J2 - CELEST MECH DYN ASTR VL - 92 PY - 2005 IS - 1-3 SP - 113 EP - 121 PG - 9 SN - 0923-2958 DO - 10.1007/s10569-004-3114-5 UR - https://m2.mtmt.hu/api/publication/2215810 ID - 2215810 N1 - Cited By :40 Export Date: 31 August 2023 Correspondence Address: Érdi, B.; Department of Astronomy, Pazmany Peter s.1/A, H-1117 Budapest, Hungary; email: B.Erdi@astro.elte.hu AB - The stability of co-orbital motions is investigated in such exoplanetary systems, where the only known giant planet either moves fully in the habitable zone, or leaves it for some part of its orbit. If the regions around the triangular Lagrangian points are stable, they are possible places for smaller Trojan-like planets. We have determined the nonlinear stability regions around the Lagrangian point L 4 of nine exoplanetary systems in the model of the elliptic restricted three-body problem by using the method of the relative Lyapunov indicators. According to our results, all systems could possess small Trojan-like planets. Several features of the stability regions are also discussed. Finally, the size of the stability region around L 4 in the elliptic restricted three-body problem is determined as a function of the mass parameter and eccentricity. © Springer 2005. LA - English DB - MTMT ER - TY - JOUR AU - Schwarz, R AU - Pilat-Lohinger, E AU - Dvorak, R AU - Érdi, Bálint AU - Sándor, Zsolt TI - Trojans in habitable zones JF - ASTROBIOLOGY J2 - ASTROBIOLOGY VL - 5 PY - 2005 IS - 5 SP - 579 EP - 586 PG - 8 SN - 1531-1074 DO - 10.1089/ast.2005.5.579 UR - https://m2.mtmt.hu/api/publication/2215809 ID - 2215809 AB - With the aid of numerical experiments we examined the dynamical stability of fictitious terrestrial planets in 1:1 mean motion resonance with Jovian-like planets of extrasolar planetary systems. In our stability study of the so-called "Trojan" planets in the habitable zone, we used the restricted three-body problem with different mass ratios of the primary bodies. The application of the three-body problem showed that even massive Trojan planets can be stable in the 1:1 mean motion resonance. From the 117 extrasolar planetary systems only 11 systems were found with one giant planet in the habitable zone. Out of this sample set we chose four planetary systems - HD17051, HD27442, HD28185, and HD108874 - for further investigation. To study the orbital behavior of the stable zone in the different systems, we used direct numerical computations (Lie Integration Method) that allowed us to determine the escape times and the maximum eccentricity of the fictitious "Trojan planets." © Mary Ann Liebert, Inc. LA - English DB - MTMT ER -