scholarly journals Formation of single-moon systems around gas giants

2020 ◽  
Vol 635 ◽  
pp. L4 ◽  
Author(s):  
Yuri I. Fujii ◽  
Masahiro Ogihara
Keyword(s):  
Giant Planet ◽  
Orbital Evolution ◽  
Effect Of Temperature ◽  
Temperature Structure ◽  
Satellite Formation ◽  
Satellite Systems ◽  
Evolution Stage ◽  
First Time ◽  
Final Evolution ◽  
Orbital Migration

Context. Several mechanisms have been proposed to explain the formation process of satellite systems, and relatively large moons are thought to be born in circumplanetary disks. Making a single-moon system is known to be more difficult than multiple-moon or moonless systems. Aims. We aim to find a way to form a system with a single large moon, such as Titan around Saturn. We examine the orbital migration of moons, which change their direction and speed depending on the properties of circumplanetary disks. Methods. We modeled dissipating circumplanetary disks with taking the effect of temperature structures into account and calculated the orbital evolution of Titan-mass satellites in the final evolution stage of various circumplanetary disks. We also performed N-body simulations of systems that initially had multiple satellites to see whether single-moon systems remained at the end. Results. The radial slope of the disk-temperature structure characterized by the dust opacity produces a patch of orbits in which the Titan-mass moons cease inward migration and even migrate outward in a certain range of the disk viscosity. The patch assists moons initially located in the outer orbits to remain in the disk, while those in the inner orbits fall onto the planet. Conclusions. We demonstrate for the first time that systems can form that have only one large moon around giant planet. Our N-body simulations suggest satellite formation was not efficient in the outer radii of circumplanetary disks.

scholarly journals The Origin of Commensurabilities in the Satellite Systems

1974 ◽  
Vol 62 ◽  
pp. 57-58
Author(s):  
S. F. Dermott
Keyword(s):  
Formation Process ◽  
Orbital Evolution ◽  
Dissipation Function ◽  
Chemical Compositions ◽  
Tidal Evolution ◽  
Tidal Dissipation ◽  
Satellite Formation ◽  
Satellite Systems ◽  
Tidal Forces ◽  
Frequency Independent

The distribution of orbits in the satellite systems of the major planets is definitely nonrandom as there is a marked preference for commensurability among pairs of mean motions in these systems. If this preference is not the result of a formation process then it follows that since the time of satellite formation dynamical evolution has occurred. In this paper (a full version of which is to be submitted to another journal) I show that there is a bulk of evidence in favour of the hypothesis that orbital evolution has occurred as the result of tidal dissipation in the planets. This evidence can be listed as follows:(i) In a tidally evolved satellite system there should be a linear correlation between log (orbital radius) and log (satellite mass). The expected correlation is observed among the inner satellites of Saturn and Uranus, the slope of the log-log plots being consistent with an amplitude and frequency independent Q (the tidal dissipation function). The correlation in Saturn's system must be largely due to either a formation process or possibly an early amplitude and frequency dependent tidal process, but certainly the present satellite distribution is completely consistent with the tidal hypothesis.(ii) If Q is amplitude- and frequency-independent then the Mimas-Tethys and Enceladus-Dione resonances are stable under the action of tidal forces. This is an important result as it indicates that the necessary tidal dissipation occurred in the solid parts of the planets. Whether or not these planets have any solid parts at present is a matter of dispute.(iii) The tidal hypothesis can account for the formation (capture into libration) of the Mimas-Tethys and Enceladus-Dione resonances.(iv) If it is allowed that the age of the Mimas-Tethys resonance is not small (> 108 yr) in comparison with that of the solar system and that orbital evolution since the time of satellite formation has been appreciable then it can be shown that tidal forces (with Q amplitude- and frequency-independent) can account for the present large amplitude of libration of this resonance.(v) If tidal evolution in the satellite systems of Jupiter and Saturn has been appreciable then from the present orbits of Io and Mimas it can be deduced that Q (Jupiter) ~1.1 × 105 and Q (Saturn) ~1.2 × 105. As the masses of the two satellites differ by a factor ~2000 and the amplitudes of the tides they raise on their respective planets differ by a factor ~ 5000 this agreement in the Q-values is somewhat remarkable. But as the stability of the Mimas-Tethys and Enceladus-Dione resonances demands that Q is amplitude- and frequency-independent and as the chemical compositions and structures of Jupiter and Saturn are probably similar then one should expect the Q's of these planets to be similar and thus the result supports the tidal hypothesis.(vi) Finally, as the values of Q are so very high it would be remarkable if tidal evolution had not taken place.

scholarly journals Orbital evolution of Saturn’s satellites due to the interaction between the moons and the massive rings

2020 ◽  
Vol 640 ◽  
pp. L15
Author(s):  
Ayano Nakajima ◽  
Shigeru Ida ◽  
Yota Ishigaki
Keyword(s):  
Orbital Evolution ◽  
The Self ◽  
Mean Motion Resonances ◽  
First Order ◽  
Mean Motion ◽  
Saturn’S Satellites ◽  
Orbital Configuration ◽  
Self Gravity ◽  
Spiral Arm ◽  
Orbital Migration

Context. Saturn’s mid-sized moons (satellites) have a puzzling orbital configuration with trapping in mean-motion resonances with every-other pairs (Mimas-Tethys 4:2 and Enceladus-Dione 2:1). To reproduce their current orbital configuration on the basis of a recent model of satellite formation from a hypothetical ancient massive ring, adjacent pairs must pass first-order mean-motion resonances without being trapped. Aims. The trapping could be avoided by fast orbital migration and/or excitation of the satellite’s eccentricity caused by gravitational interactions between the satellites and the rings (the disk), which are still unknown. In our research we investigate the satellite orbital evolution due to interactions with the disk through full N-body simulations. Methods. We performed global high-resolution N-body simulations of a self-gravitating particle disk interacting with a single satellite. We used N ∼ 105 particles for the disk. Gravitational forces of all the particles and their inelastic collisions are taken into account. Results. Dense short-wavelength wake structure is created by the disk self-gravity and a few global spiral arms are induced by the satellite. The self-gravity wakes regulate the orbital evolution of the satellite, which has been considered as a disk spreading mechanism, but not as a driver for the orbital evolution. Conclusions. The self-gravity wake torque to the satellite is so effective that the satellite migration is much faster than was predicted with the spiral arm torque. It provides a possible model to avoid the resonance capture of adjacent satellite pairs and establish the current orbital configuration of Saturn’s mid-sized satellites.

The equatorial wind structure in Jupiter's stratosphere from direct wind and temperature measurements with ALMA and IRTF/TEXES

2021 ◽  
Author(s):  
Bilal Benmahi ◽  
Thibault Cavalié ◽  
Thomas K. Greathouse ◽  
Vincent Hue
Keyword(s):  
Temperature Measurements ◽  
Tropical Region ◽  
Temperature Structure ◽  
Tropical Zone ◽  
Horizontal Structure ◽  
Thermal Wind ◽  
Wind Speeds ◽  
Wind Structure ◽  
Stratospheric Wind ◽  
First Time

<p>The stratosphere of Jupiter is subject to an equatorial oscillation of its temperature structure with a quasi-period of 4 years (Orton et al. 1991, Leovy et al. 1991) which could result in a complex vertical and horizontal structure of prograde and retrograde jets. Yet, the stratospheric wind structure in Jupiter’s equatorial zone has never been directly measured. It has only been inferred in the tropical region from the thermal wind balance using temperature measurements in the stratosphere and the cloud-top wind speeds as a boundary condition (Flasar et al. 2004). However, the temperatures are not well-constrained between the upper troposphere and the middle stratosphere from the observations.</p><p>In this paper, we obtain for the first time an auto-consistent determination of the tropical wind structure using wind and temperature measurements all performed in the stratosphere. The wind speeds have been measured by Cavalié et al. (submitted) at 1 mbar in the stratosphere of Jupiter in the equatorial and tropical zone in March 2017 with ALMA. The stratospheric thermal field was measured five days apart in the low-to-mid latitudes with the IRTF/TEXES instrument (Giles et al. 2020). For the wind derivation, we use the thermal wind equation (Pedlosky, 1979) and equatorial thermal wind equation (Marcus et al. 2019). We will present and discuss our results.</p><p>This paper is a follow-up to the EGU21-8726 paper.</p>

The equatorial wind structure in Jupiter’s stratosphere from direct wind and temperature measurements with ALMA and IRTF/TEXES

2021 ◽  
Author(s):  
Bilal Benmahi ◽  
Thibault Cavalié ◽  
Thomas K. Greathouse ◽  
Vincent Hue ◽  
Rohini Giles ◽  
...  
Keyword(s):  
Tropical Region ◽  
Temperature Structure ◽  
Horizontal Structure ◽  
Tropical Regions ◽  
Upper Troposphere ◽  
Thermal Wind ◽  
Wind Speeds ◽  
Wind Structure ◽  
First Time ◽  
Middle Stratosphere

<p>Since 30 years, an equatorial oscillation of the temperature structure with a quasi-period of 4 years has been discovered in the atmosphere of Jupiter (Orton et al. 1991, Leovy et al. 1991). This phenomenon results in a complex vertical and horizontal structure of prograde and retrograde jets. However, the wind structure of the stratosphere in the equatorial zone of Jupiter has not been measured directly. It has only been inferred in the tropical region from the thermal wind balance using temperatures measured in the jovian stratosphere and the cloud-top wind speeds measured as a initial condition (e.g. Flasar et al. 2004). But temperatures are not constrained between the upper troposphere and the middle stratosphere from observations, limiting thus the accuracy of the thermal wind balance.</p> <p>In this study, we derive self-consistently for the first time the structure of the tropical winds by utilizing wind and temperature observations all performed in the stratosphere. The wind speeds were obtained by Cavalié et al. (2021) at 1 mbar in Jupiter's stratosphere in both the equatorial and tropical regions in March 2017 with ALMA. The stratospheric thermal field was measured a few days before from the equator to the mid-latitudes with Gemini/TEXES (Giles et al. 2020). For the derivation of the wind, we use both the thermal wind equation (Pedlosky 1979) and the equatorial thermal wind equation (Marcus et al. 2019). In this paper, we will present and discuss our results.</p>

scholarly journals A gas-poor planetesimal capture model for the formation of giant planet satellite systems

Icarus ◽  
2006 ◽  
Vol 181 (2) ◽  
pp. 486-509 ◽  
Author(s):  
Paul R. Estrada ◽  
Ignacio Mosqueira
Keyword(s):  
Giant Planet ◽  
Satellite Systems ◽  
Planet Satellite

scholarly journals Performance of Absolute Real-Time Multi-GNSS Kinematic Positioning

2018 ◽  
Vol 53 (2) ◽  
pp. 75-88 ◽  
Author(s):  
Kamil Kazmierski
Keyword(s):  
Real Time ◽  
Rapid Development ◽  
Vertical Component ◽  
Solution Quality ◽  
Vertical Coordinate ◽  
Satellite Systems ◽  
High Tension ◽  
Point Positioning ◽  
Time Standard ◽  
First Time

Abstract Recently, we observe the rapid development of the Global Navigational Satellite Systems (GNSS), including autonomous positioning techniques, such as Precise Point Positioning (PPP). The GNSS have different conceptions, different spacecraft and use different types of orbits which is why the quality of real-time orbit and clock products is inconsistent, thus, the appropriate approach of the multi-GNSS observation processing is needed to optimize the solution quality. In this paper, the kinematic field experiment is conducted in order to examine multi-GNSS real-time Standard Point Positioning (SPP) and PPP performance. The test was performed on the 26 km-long car route through villages, forests, the city of Wrocław, crossing under viaducts and a high tension line. For the first time, the solution is based on GPS + GLONASS + Galileo + BeiDou observations using streamed corrections for orbits and clocks with two different weighting scenarios. Thanks to the usage of the multi-GNSS constellation the number of positioning epochs possible to determine increases by 10%. The results show also that the appropriate weighting approach can improve the root mean square error in the SPP solution by about 13% and 42% for the horizontal and vertical coordinate components, respectively. In the case of PPP, the maximum quality improvement equals 70% for the horizontal component and the results for the vertical component are comparable with those obtained for the GPS-only solution.

scholarly journals Orbital migration and the frequency of giant planet formation

2002 ◽  
Vol 394 (1) ◽  
pp. 241-251 ◽  
Author(s):  
D. E. Trilling ◽  
J. I. Lunine ◽  
W. Benz
Keyword(s):  
Planet Formation ◽  
Giant Planet ◽  
Orbital Migration

Structures and phase transitions in the ordered double perovskites Ba2BiIIIBiVO6 and Ba2BiIIISbVO6

2006 ◽  
Vol 62 (4) ◽  
pp. 537-546 ◽  
Author(s):  
Brendan J. Kennedy ◽  
Christopher J. Howard ◽  
Kevin S. Knight ◽  
Zhaoming Zhang ◽  
Qingdi Zhou
Keyword(s):  
Phase Transitions ◽  
Low Temperature ◽  
Neutron Powder Diffraction ◽  
Temperature Structure ◽  
Double Perovskites ◽  
Monoclinic Structure ◽  
Bismuth Antimony ◽  
Higher Order Terms ◽  
Temperature Ranges ◽  
First Time

High-resolution neutron powder diffraction has been used to investigate the structures and phase transitions in the double perovskites Ba2Bi3+Bi5+O6 (dibarium dibismuth hexaoxide) and Ba2BiSbO6 (dibarium bismuth antimony hexaoxide) in the temperature ranges 4.2–973 and 4.2–625 K, respectively. The charge-ordered bismuthate adopts four structures in the temperature range – monoclinic in P21/n, monoclinic in I2/m, rhombohedral in R\bar 3, and finally cubic in Fm\bar 3 m. The low-temperature monoclinic structure has been determined for the first time. The transitions from P21/n to I2/m, at 132 K, and R\bar 3 to Fm\bar 3m, at 820 K, are tricritical in nature; the transition from I2/m to R\bar 3 at ca 430 K is discontinuous. The behaviour of Ba2BiSbO6 is very similar, except that the transition temperatures are lower – 250 K for I2/m to R\bar 3 and 515 K for R\bar 3 to Fm\bar 3m – and the low-temperature structure is not formed at all. The R\bar 3 to Fm\bar 3 m transition in this compound is closer to second order in nature, although there is evidence for some contribution from higher-order terms.

Development of Microplitis rufiventris Kok at different temperatures

1980 ◽  
Vol 94 (3) ◽  
pp. 739-740 ◽  
Author(s):  
E. M. Hegazi ◽  
M. O. Kolaib ◽  
M. I. Abd-El Fattah
Keyword(s):  
Spodoptera Littoralis ◽  
Spodoptera Exigua ◽  
Effect Of Temperature ◽  
Cotton Leaf ◽  
Microplitis Rufiventris ◽  
Cotton Leafworm ◽  
Larval Parasite ◽  
Different Temperatures ◽  
First Time

The solitary larval parasite Microplitis rufiventris Kok was recorded for the first time in Egypt by El-Minshawy (1963), parasitizing the lesser cotton leafworm, Spodoptera exigua Hbn. Since it could be an effective summer parasite of the cotton leaf-worm, Spodoptera littoralis Boisd., studies on aspects of its biology by Hegazi (1976), and Hegazi, Hammad & El-Minshawy (1977) have been extended to include the effect of temperature on its development.

scholarly journals Arrhenius Plot Analysis of the Temperature Effect on the Biodegradation Rate of 2-chloro-4-nitrophenol

2020 ◽  
Vol 8 (2) ◽  
pp. 219
Author(s):  
Mohd Yunus Shukor
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Regression Analysis ◽  
Arrhenius Plot ◽  
Activation Energies ◽  
Effect Of Temperature ◽  
Biodegradation Rate ◽  
Arrhenius Model ◽  
Plot Analysis ◽  
First Time

Several models are available to determine the effect of temperature on the growth rate of microorganisms on substrates. An example is Arrhenius model, which is very popular because it has few parameters. For the first time, a discontinuous chevron-like graph of apparent activation energy based on the Arrhenius plot on the growth of 2-chloro-4-nitrophenol by Cupriavidus sp. is reported. The plot of ln mm against 1/T shows a discontinuous chevron-like graph for the entire investigated temperature range with an inflection at 27.75°C. This indicates that the existence of 2 activation energies for growth on 2-chloro-4-nitrophenol ranges from 20 to 40°C. Furthermore, a regression analysis from 20–25°C and 30–40°C results in activation energies of 88.71 kJmol-1 and 75.16kJ mol-1, respectively. This is probably the first time a Chevron-like graph was observed for the Arrhenius plot on the effect of temperature on the growth rate of 2-chloro-4-nitrophenol.

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