scholarly journals Co-orbital exoplanets from close-period candidates: the TOI-178 case

2019 ◽  
Vol 624 ◽  
pp. A46 ◽  
Author(s):  
A. Leleu ◽  
J. Lillo-Box ◽  
M. Sestovic ◽  
P. Robutel ◽  
A. C. M. Correia ◽  
...  
Keyword(s):  
Solar System ◽  
Time Scale ◽  
Planetary System ◽  
Angular Separation ◽  
Orbital System ◽  
Long Term Stability ◽  
Orbital Periods ◽  
In Transit ◽  
Horseshoe Orbit

Despite the existence of co-orbital bodies in the solar system, and the prediction of the formation of co-orbital planets by planetary system formation models, no co-orbital exoplanets (also called trojans) have been detected thus far. Here we study the signature of co-orbital exoplanets in transit surveys when two planet candidates in the system orbit the star with similar periods. Such a pair of candidates could be discarded as false positives because they are not Hill-stable. However, horseshoe or long-libration-period tadpole co-orbital configurations can explain such period similarity. This degeneracy can be solved by considering the transit timing variations (TTVs) of each planet. We subsequently focus on the three-planet-candidate system TOI-178: the two outer candidates of that system have similar orbital periods and were found to have an angular separation close to π∕3 during the TESS observation of sector 2. Based on the announced orbits, the long-term stability of the system requires the two close-period planets to be co-orbital. Our independent detrending and transit search recover and slightly favour the three orbits close to a 3:2:2 resonant chain found by the TESS pipeline, although we cannot exclude an alias that would put the system close to a 4:3:2 configuration. We then analyse the co-orbital scenario in more detail, and show that despite the influence of an inner planet just outside the 2:3 MMR, this potential co-orbital system could be stable on a gigayear time-scale for a variety of planetary masses, either on a trojan or a horseshoe orbit. We predict that large TTVs should arise in such a configuration with a period of several hundred days. We then show how the mass of each planet can be retrieved from these TTVs.

scholarly journals Close encounters with the Death Star: Interactions between collapsed bodies and the Solar System

2021 ◽  
Vol 648 ◽  
pp. L2 ◽  
Author(s):  
Václav Pavlík ◽  
Steven N. Shore
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Solar System ◽  
Planetary System ◽  
Planetary Systems ◽  
Symplectic Integrator ◽  
Orbital Parameters ◽  
Long Term Stability ◽  
Complete Disruption

Aims. We aim to investigate the consequences of a fast massive stellar remnant – a black hole (BH) or a neutron star (NS) – encountering a planetary system. Methods. We modelled a close encounter between the actual Solar System (SS) and a 2 M⊙ NS and a 10 M⊙ BH, using a few-body symplectic integrator. We used a range of impact parameters, orbital phases at the start of the simulation derived from the current SS orbital parameters, encounter velocities, and incidence angles relative to the plane of the SS. Results. We give the distribution of possible outcomes, such as when the SS remains bound, when it suffers a partial or complete disruption, and in which cases the intruder is able to capture one or more planets, yielding planetary systems around a BH or a NS. We also show examples of the long-term stability of the captured planetary systems.

scholarly journals Long-term stability of the HR 8799 planetary system without resonant lock

2016 ◽  
Vol 592 ◽  
pp. A147 ◽  
Author(s):  
Ylva Götberg ◽  
Melvyn B. Davies ◽  
Alexander J. Mustill ◽  
Anders Johansen ◽  
Ross P. Church
Keyword(s):  
Planetary System ◽  
Term Stability ◽  
Long Term Stability

The Long-Term Stability of Becquerelite

1994 ◽  
Vol 353 ◽  
Author(s):  
R.J. Finch ◽  
J. Suksi ◽  
K. Rasilainen ◽  
R.C. Ewing
Keyword(s):  
Ground Water ◽  
Time Scale ◽  
Solubility Product ◽  
Term Stability ◽  
Long Term Stability ◽  
Uranium Series ◽  
Lower Solubility ◽  
Geologic Disposal ◽  
Petrographic Analyses

AbstractUranium-series disequilibria data, in conjunction with petrographic analyses, indicate that the uranyl oxide hydrate becquerelite can persist for hundreds of thousands of years, possibly longer. Becquerelite probably forms continuously as ground water compositions permit and is resistant to U leaching by ground water. On the time scale of interest for the geologic disposal of spent UO2 nuclear fuel, becquerelite is a long-lived sink for uranium in oxidizing, U and Ca-bearing ground waters. Such long-term stability also supports recent solubility experiments that indicate natural becquerelite has a lower solubility product than that determined for synthetic becquerelites.

Long-term stability and performance of solar system instrumentation

1984 ◽  
Vol 5 (1) ◽  
pp. 21-30 ◽  
Author(s):  
N. Lior ◽  
R. T. Brish ◽  
L. Tedori ◽  
S. Koffs
Keyword(s):  
Solar System ◽  
Term Stability ◽  
Long Term Stability ◽  
And Performance

scholarly journals Fly-by encounters between two planetary systems I: Solar system analogues

2019 ◽  
Vol 488 (1) ◽  
pp. 1366-1376 ◽  
Author(s):  
Daohai Li ◽  
Alexander J Mustill ◽  
Melvyn B Davies
Keyword(s):  
Solar System ◽  
Planetary System ◽  
Planetary Systems ◽  
Open Clusters ◽  
Giant Planets ◽  
Direct Imaging ◽  
Solar Mass ◽  
Close Encounters ◽  
Large Numbers

ABSTRACTStars formed in clusters can encounter other stars at close distances. In typical open clusters in the Solar neighbourhood containing hundreds or thousands of member stars, 10–20 per cent of Solar-mass member stars are expected to encounter another star at distances closer than 100 au. These close encounters strongly perturb the planetary systems, directly causing ejection of planets or their capture by the intruding star, as well as exciting the orbits. Using extensive N-body simulations, we study such fly-by encounters between two Solar system analogues, each with four giant planets from Jupiter to Neptune. We quantify the rates of loss and capture immediately after the encounter, e.g. the Neptune analogue is lost in one in four encounters within 100 au, and captured by the flying-by star in 1 in 12 encounters. We then perform long-term (up to 1 Gyr) simulations investigating the ensuing post-encounter evolution. We show that large numbers of planets are removed from systems due to planet–planet interactions and that captured planets further enhance the system instability. While encounters can initially leave a planetary system containing more planets by inserting additional ones, the long-term instability causes a net reduction in planet number. A captured planet ends up on a retrograde orbit in half of the runs in which it survives for 1Gyr; also, a planet bound to its original host star but flipped during the encounter may survive. Thus, encounters between planetary systems are a channel to create counter-rotating planets, This would happen in around 1 per cent of systems, and such planets are potentially detectable through astrometry or direct imaging.

scholarly journals Long term stability of atomic time scales

2012 ◽  
Vol 10 (H16) ◽  
pp. 209-210
Author(s):  
G. Petit ◽  
F. Arias
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
Time Transfer ◽  
Long Term Stability ◽  
Relative Value ◽  
The Stability ◽  
Primary Standards ◽  
Stability And Accuracy ◽  
Atomic Time

AbstractWe review the stability and accuracy achieved by the reference atomic time scales TAI and TT(BIPM). We show that they presently are in the low 10−16 in relative value, based on the performance of primary standards, of the ensemble time scale and of the time transfer techniques. We consider how the 1 × 10−16 value could be reached or superseded and which are the present limitations to attain this goal.

scholarly journals The chaotic nature of TRAPPIST-1 planetary spin states

2019 ◽  
Vol 488 (4) ◽  
pp. 5739-5747 ◽  
Author(s):  
Alec M Vinson ◽  
Daniel Tamayo ◽  
Brad M S Hansen
Keyword(s):  
Central Star ◽  
Spin States ◽  
Habitable Zone ◽  
Long Term Stability ◽  
Mean Motion ◽  
Stable Attractor ◽  
The Mean ◽  
Orbital Periods ◽  
Chaotic Nature

ABSTRACT The TRAPPIST-1 system has seven known terrestrial planets arranged compactly in a mean motion resonant chain around an ultracool central star, some within the estimated habitable zone. Given their short orbital periods of just a few days, it is often presumed that the planets are tidally locked such that the spin rate is equal to that of the orbital mean motion. However, the compact, and resonant, nature of the system implies that there can be significant variations in the mean motion of these planets due to their mutual interactions. We show that such fluctuations can then have significant effects on the spin states of these planets. In this paper, we analyse, using detailed numerical simulations, the mean motion histories of the three planets that are thought to lie within or close to the habitable zone of the system: planets d, e, and f. We demonstrate that, depending on the strength of the mutual interactions within the system, these planets can be pushed into spin states which are effectively non-synchronous. We find that it can produce significant libration of the spin state, if not complete circulation in the frame co-rotating with the orbit. We also show that these spin states are likely to be unable to sustain long-term stability, with many of our simulations suggesting that the spin evolves, under the influence of tidal synchronization forces, into quasi-stable attractor states, which last on time-scales of thousands of years.

scholarly journals Towards the characterization of the hot Neptune/super-Earth population around nearby bright stars

2008 ◽  
Vol 4 (S253) ◽  
pp. 502-505 ◽  
Author(s):  
C. Lovis ◽  
M. Mayor ◽  
F. Bouchy ◽  
F. Pepe ◽  
D. Queloz ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Extrasolar Planets ◽  
Large Population ◽  
Long Term Stability ◽  
Data Points ◽  
Solar Type ◽  
Low Mass ◽  
Orbital Periods

AbstractThe HARPS search for low-mass extrasolar planets has been ongoing for more than 4 years, targeting originally about 400 bright FGK dwarfs in the solar neighbourhood. The published low-mass planetary systems coming from this survey are fully confirmed by subsequent observations, which demonstrate the sub-m/s long-term stability reached by HARPS. The complex RV curves of these systems have led us to focus on a smaller sample of stars, accumulating more data points per star. We perform a global search in our data to assess the existence of the large population of ice giants and super-Earths predicted by numerical simulations of planet formation. We indeed detect about 45 candidates having minimum masses below 30 M⊕ and orbital periods below 50 days. These numbers are preliminary since the existence of these objects has to be confirmed by subsequent observations. However, they indicate that about 30% of solar-type stars may have such close-in, low-mass planets. Some emerging properties of this low-mass population are presented. We finally discuss the prospects for finding transiting objects among these candidates, which may possibly yield the first nearby, transiting super-Earth.

scholarly journals Photometric follow-up of the transiting planetary system TrES-3: transit timing variation and long-term stability of the system★

2013 ◽  
Vol 432 (2) ◽  
pp. 944-953 ◽  
Author(s):  
M. Vaňko ◽  
G. Maciejewski ◽  
M. Jakubík ◽  
T. Krejčová ◽  
J. Budaj ◽  
...  
Keyword(s):  
Planetary System ◽  
Term Stability ◽  
Long Term Stability

An attempt to constrain Planet Nine’s orbit and position via resonant confinement of distant TNOs

2020 ◽  
Vol 494 (2) ◽  
pp. 2045-2052
Author(s):  
Brynna G Downey ◽  
Alessandro Morbidelli
Keyword(s):  
Numerical Simulations ◽  
Time Scale ◽  
Semimajor Axis ◽  
Giant Planets ◽  
Term Survival ◽  
Long Term Survival ◽  
3D Simulations ◽  
Orbital Periods ◽  
Strict Requirement

ABSTRACT We considered four TNOs on elongated orbits with small semimajor axis uncertainties: Sedna, 2004 VN112, 2012 VP113, and 2000 CR105. We found two sets of simultaneous near commensurabilities for these objects with a putative Planet Nine that are compatible with the current uncertainties in the objects’ orbital periods. We conducted a large number of numerical simulations of quasi-coplanar simulations (i.e. inclinations of Planet Nine and TNOs set to zero but not the giant planets) to find which values of Planet Nine’s mean anomaly and longitude of perihelion could put these objects in stable mean motion resonance (MMR) librations. We found no cases of simultaneous stable librations for multiple TNOs for more than 800 My, with most librations lasting much shorter than this time-scale. The objects 2004 VN112 and 2000 CR105 are the most unstable. Being in an MMR is not a strict requirement for long-term survival in 3D simulations, so our result cannot be used to refute Planet Nine’s existence. Nevertheless, it casts doubt and shows that theoretical attempts to constrain the position of the planet on the sky are not possible.

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