How does the Lidov–Kozai mechanism protect Quadrantids meteoroid stream from close encounters with Jupiter?

2020 ◽  
Author(s):  
Georgy E. Sambarov ◽  
Tatyana Yu. Galushina ◽  
Olga M. Syusina

<p>The dynamical evolution of simulated meteoroid stream of the Quadrantids ejected from the parent body of the asteroid (196256) 2003 EH1 expects possible scenario for resonant motion. We found a peculiar behavior for this stream. Here, we show that the orbits of some ejected particles are strongly affected by the Lidov–Kozai mechanism that protects them from close encounters with Jupiter. Lack of close encounters with Jupiter leads to a rather smooth growth in the parameter MEGNO (Mean Exponential Growth factor of Nearby Orbits) and the behavior imply the stable motion of simulation particles of the Quadrantids meteoroid stream. A rather smooth path with nearly constant semi-major axis is obtained due to lack of close encounters with Jupiter. The coupled oscillation of the three orbital parameters, e, i, and ω, for stable ejected particles is observed.</p> <p>However, close encounters with Jupiter are not treated by the Kozai formalism and can transfer particles away from the Kozai trajectories for unstable ejected particles over time. Other ejected particles have chaotic motion from simulations of the orbit of meteoroids are not affected by the Lidov – Kozai mechanism. We suppose that the reasons are the frequent close approaches of the ejected particles with Jupiter and they located near mean motion resonance 2:1J with Jupiter. The motion of these objects has considered to be chaotic in a long-time scale, and the close encounters with Jupiter are supposed to be the cause of the faster chaos. Another reason is that a non-resonant state near the mean motion resonance 2:1J has a strong influence on the motion of the Quadrantid meteor stream. This “weak chaos” is largely confined to the true anomaly. Consequently, the shape of the orbit can be computed reliably over much longer time scales than can the body’s position within the orbit. High value of the parameter MEGNO are due to frequent changes in semimajor axis induced by multiple close encounters with Jupiter near Hill sphere. We finally note that the chaotic behavior of the simulation particles of meteor stream may be caused not only by close encounter with planets but also by unstable mean motion or secular resonances.</p> <p>We conjecture that the reasons of chaos are the overlap of stable secular resonances and unstable mean motions resonances and close and/or multiple close encounters with the major planets. The orbits of some ejected particles are strongly affected by the Lidov–Kozai mechanism that protects them from close encounters with Jupiter that leads to a rather smooth growth in the parameter MEGNO and the behavior imply the stable motion of simulation particles of the Quadrantids meteoroid stream.</p> <p>The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian Federation (theme No. 0721-2020-0049)</p> <p> </p> <p><strong>References</strong></p> <p>Abedin, A., Spurný, P., Wiegert, P., Pokorný, P., Borovi cka, J., Brown, P., 2015. On the age and formation mechanism of the core of the Quadrantid meteoroid stream. Icarus 261, 100–117.</p> <p>Cincotta, P.M., Girdano, C.M., Simo, C., 2003. Phase space structure of multi-dimensional systems by means of the mean exponential growth factor of nearby orbits. Phys. Nonlinear Phenom. 182 (3–4), 151–178.</p> <p>Chirikov, B.V., 1979. A universal instability of many-dimensional oscillator systems. Phys. Rep. 52 (5), 263–379.</p> <p>Galushina, T.Yu, Sambarov, G.E., 2017. The dynamical evolution and the force model for asteroid (196256) 2003 EH1. Planet. Space Sci. 142, 38.</p> <p>Galushina, T.Yu, Sambarov, G.E., 2019. Dynamics of asteroid 3200 Phaethon under overlap of different resonances. Sol. Syst. Res. 53 (3), 215–223.</p> <p>Gonczi, R., Rickman, H., Froeschle, C., 1992. The connection between Comet P/Machholz and the Quadrantid meteor. Mon. Not. Roy. Astron. Soc. 254, 627.</p> <p>Hughes, D.W., Taylor, I.W., 1977. Observations of overdense Quadrantid radio meteors and the variation of the position of stream maxima with meteor magnitude. Mon. Not. Roy. Astron. Soc. 181, 517.</p> <p>Kozai, Y., 1962. Secular perturbations of asteroids with high inclination and eccentricity. Astron. J. 67, 591–598.</p> <p>Lidov, M.L., 1962. The evolution of orbits of artificial satellites of planets under the action of gravitational perturbations of external bodies. Planet. Space Sci. 9, 719.</p> <p>Williams, I.P., Ryabova, G.O., Baturin, A.P., Chernitsov, A.M., 2004a. The parent of the Quadrantid meteoroid stream and asteroid 2003 EH1. Mon. Not. Roy. Astron. Soc. 355 (4), 1171–1181.</p>

2019 ◽  
Vol 631 ◽  
pp. A112 ◽  
Author(s):  
L. Neslušan ◽  
M. Hajduková

Aims. We study the meteoroid stream of the long-period comet C/1963 A1 (Ikeya) to predict the meteor showers originating in this comet. We also aim to identify the predicted showers with their real counterparts. Methods. We modeled 23 parts of a theoretical meteoroid stream of the parent comet considered. Each of our models is characterized by a single value of the evolutionary time and a single value of the strength of the Poynting–Robertson effect. The evolutionary time is defined as the time before the present when the stream is modeled and when we start to follow its dynamical evolution. This period ranges from 10 000 to 80 000 yr. In each model, we considered a stream consisting of 10 000 test particles that dynamically evolve, and their dynamics is followed via a numerical integration up to the present. At the end of the integration, we analyzed the mean orbital characteristics of particles in the orbits approaching Earth’s orbit, which thus enabled us to predict a shower related to the parent comet. We attempted to identify each predicted shower with a shower recorded in the International Astronomical Union Meteor Data Center list of all showers. In addition, we tried to separate, often successfully, a real counterpart of each predicted shower from the databases of real meteors. Results. Many modeled parts of the stream of comet C/1963 A1 are identified with the corresponding real showers in three video-meteor databases. No real counterpart is found in the IAU MDC photographic or radio-meteor data. Specifically, we predict five showers related to C/1963 A1. Two predicted showers are identified with π-Hydrids #101 and δ-Corvids #729. The third predicted shower is only vaguely similar to November α-Sextantids #483, when its mean orbit is compared with the mean orbit of the November α-Sextantids in the IAU MDC list of all showers. However, the prediction is very consistent with the corresponding showers newly separated from three video databases. Another predicted shower has no counterpart in the IAU MDC list, but there is a good match of the prediction and a shower that we separated from the Cameras for Allsky Meteor Surveillance video data. We name this new shower ϑ-Leonids. The last of the predicted showers should be relatively low in number and, hence, no real counterparts were either found in the IAU MDC list or separated from any considered database.


2019 ◽  
Vol 623 ◽  
pp. A13 ◽  
Author(s):  
D. Tomko ◽  
L. Neslušan

Aims. We present a study of the meteor complex of the short-period comet 2P/Encke. Methods. For five perihelion passages of the parent comet in the past, we modeled the associated theoretical stream. Specifically, each of our models corresponds to a part of the stream characterized with a single value of the evolutionary time and a single value of the strength of the Poynting–Robertson effect. In each model, we follow the dynamical evolution of 10 000 test particles via a numerical integration. The integration was performed from the time when the set of test particles was assumed to be ejected from the comet’s nucleus up to the present. At the end of the integration, we analyzed the mean orbital characteristics of those particles that approached the Earth’s orbit, and thus created a meteor shower or showers. Using the mean characteristics of the predicted shower, we attempted to select its real counterpart from each of five considered databases (one photographic, three video, and one radio-meteor). If at least one attempt was successful, the quality of the prediction was evaluated. Results. The modeled stream of 2P approaches the Earth’s orbit in several filaments with the radiant areas grouped in four cardinal directions of ecliptical showers. These groups of radiant areas are situated symmetrically with respect to the apex of the Earth’s motion around the Sun. Specifically, we found that showers #2, #17, #156, #172, #173, #215, #485, #624, #626, #628, #629, #632, #634, #635, #636, and #726 in the IAU-MDC list of all showers are dynamically related to 2P. In addition, we found five new 2P-related showers in the meteor databases considered.


2019 ◽  
Vol 627 ◽  
pp. A73 ◽  
Author(s):  
M. Hajduková ◽  
L. Neslušan

Aims. We study the meteoroid stream of the long-period comet C/1975 T2 (Suzuki-Saigusa-Mori). This comet was suggested as the parent body of the established λ-Ursae Majorid meteor shower, No. 524. Methods. We modeled 32 parts of a theoretical meteoroid stream of the parent comet considered. Each of our models is characterized with a single value of the evolutionary time and a single value of the strength of Poynting-Robertson effect. The evolutionary time ranges from 10 000 to 80 000 yr. It is the period during which the evolution of the stream part is followed. In each model, the dynamical evolution of 10 000 test particles was then followed, via a numerical integration, from the time of the modeling up to the present. At the end of the integration, we analyzed the mean orbital characteristics of particles in the orbits that approach the Earth’s orbit, which thus enabled us to predict a shower related to the parent comet. The predicted shower was subsequently compared with its observed counterparts. We separated the latter from the databases of real meteors. As well, we attempted to identify the predicted shower to a shower recorded in the International Astronomical Union Meteor Data Center (IAU MDC) list of all showers. Results. Almost all modeled parts of the stream of comet C/1975 T2 are identified with the corresponding real shower in three video-meteor databases. No real counterpart is found in the IAU MDC photographic or radio-meteor data. In the IAU MDC list of showers and in our current study, this shower is identified with the established λ-Ursae Majorid shower, No. 524. Hence, our modeling confirms the results of previous authors. At the same time we exclude an existence of other meteor shower associated with C/1975 T2.


1974 ◽  
Vol 22 ◽  
pp. 193-203
Author(s):  
L̆ubor Kresák

AbstractStructural effects of the resonance with the mean motion of Jupiter on the system of short-period comets are discussed. The distribution of mean motions, determined from sets of consecutive perihelion passages of all known periodic comets, reveals a number of gaps associated with low-order resonance; most pronounced are those corresponding to the simplest commensurabilities of 5/2, 2/1, 5/3, 3/2, 1/1 and 1/2. The formation of the gaps is explained by a compound effect of five possible types of behaviour of the comets set into an approximate resonance, ranging from quick passages through the gap to temporary librations avoiding closer approaches to Jupiter. In addition to the comets of almost asteroidal appearance, librating with small amplitudes around the lower resonance ratios (Marsden, 1970b), there is an interesting group of faint diffuse comets librating in characteristic periods of about 200 years, with large amplitudes of about±8% in μ and almost±180° in σ, around the 2/1 resonance gap. This transient type of motion appears to be nearly as frequent as a circulating motion with period of revolution of less than one half that of Jupiter. The temporary members of this group are characteristic not only by their appearance but also by rather peculiar discovery conditions.


1991 ◽  
Vol 128 (2) ◽  
pp. 197-204 ◽  
Author(s):  
F. J. Ballard ◽  
S. E. Knowles ◽  
P. E. Walton ◽  
K. Edson ◽  
P. C. Owens ◽  
...  

ABSTRACT Incubation of 125I-labelled insulin-like growth factor-I (IGF-I) with rat plasma at 4 °C led to the transfer of approximately half the radioactivity to 150 kDa and smaller complexes with IGF-binding proteins. The extent of association was greater with labelled IGF-II and essentially absent with the truncated IGF-I analogue, des(1–3)IGF-I. A greater degree of binding of IGF peptides with binding proteins occurred after i.v. injection of the tracers into rats, but most of the des(1–3)IGF-I radioactivity remained free. Measurement of the total plasma clearances showed the rapid removal of des(1–3)IGF-I compared with IGF-I and IGF-II; the mean clearances were 4·59, 1·20 and 1·34 ml/min per kg respectively. The mean steadystate volume of distribution was larger for des(1–3)IGF-I than for IGF-I and IGF-II (461, 167 and 181 ml/kg respectively), probably because of the differences in plasma protein binding. With all tracers, radioactivity appeared in the kidneys to a greater extent than in other organs. The amount of radioactivity found in the adrenals, brain, skin, stomach, duodenum, ileum plus jejunum and colon was in rank order, des(1–3)IGF-I > IGF-I > IGF-II. Since this ranking is the opposite of the abilities of the three IGF peptides to form complexes with plasma binding proteins, we propose that the plasma binding proteins inhibit the transfer of the growth factors to their tissue sites of action. Moreover, we suggest that IGF analogues that are cleared rapidly from blood may have greater biological potencies in vivo. Journal of Endocrinology (1991) 128, 197–204


Hypertension ◽  
2020 ◽  
Vol 76 (1) ◽  
pp. 236-243
Author(s):  
David A. Drew ◽  
Ronit Katz ◽  
Stephen Kritchevsky ◽  
Joachim H. Ix ◽  
Michael G. Shlipak ◽  
...  

FGF-23 (fibroblast growth factor 23) regulates phosphorus and vitamin D. Elevated FGF-23 is associated with incident hypertension in young- and middle-aged adults, but there is limited data in older adults. Serum FGF-23 was measured using an intact ELISA assay in 2496 participants of the Healthy Aging and Body Composition Study. The association between FGF-23 and prevalent hypertension (self-reported and confirmed by use of antihypertensive medications) and number of antihypertensive medications was determined. The associations between FGF-23 and incident hypertension, and diastolic and systolic blood pressure trajectories were evaluated over 10 years. Models were adjusted for demographics, estimated glomerular filtration rate and albuminuria, cardiovascular disease risk factors, and measures of mineral metabolism. The mean (SD) age was 75 (3) years, with 51% women, and 40% black participants. The prevalence of hypertension at baseline was 75% and the mean systolic and diastolic blood pressures were 134 (21) mm Hg and 70 (12) mm Hg, respectively. The majority of participants without hypertension at baseline developed incident hypertension (576 of 1109 or 52%). In adjusted models, each 2-fold higher FGF-23 was associated with prevalent baseline hypertension (odds ratio=1.46 [1.24–1.73]) and greater number of blood pressure medications (IRR=1.14 [1.08–1.21]) but not with baseline diastolic or systolic blood pressure. In fully adjusted longitudinal analyses, a 2-fold higher FGF-23 was associated with incident hypertension (hazard ratio=1.18 [1.03–1.36]) and worsening systolic blood pressures (β=0.24 [0.08–0.40] mm Hg per year increase), but not with diastolic blood pressures (β=0.04 [−0.04 to 0.12] mm Hg per year increase). Higher FGF-23 concentrations are associated with prevalent and incident hypertension as well as rising systolic blood pressures in community-living older adults.


2018 ◽  
Vol 74 (1) ◽  
pp. 6054-2018
Author(s):  
MAREK SZCZUBIAŁ ◽  
ROMAN DABROWSKI ◽  
WOJCIECH ŁOPUSZYŃSKI ◽  
MARIOLA BOCHNIARZ ◽  
MAGDALENA KRAWCZYK ◽  
...  

The aim of this study was the investigation of the circulating concentration of IGF-1 in female dogs with spontaneous mammary tumours. The study was performed on 34 female dogs undergoing surgery due to spontaneously occurring mammary gland tumours (24 malignant and 10 benign) and 10 clinically healthy fe-male dogs. The serum concentrations of IGF-1 were determined by specific ELISA Kit assay. The mean con-centrations of IGF-1 were significantly higher (P < 0.05) both in dogs with malignant (173.35 ± 120.45 ng/ml) and benign (130.58 ± 59.0 ng/ml) mammary tumours than in healthy controls (117.45±71.0 ng/ml). In the group of female dogs with mammary carcinomas, the mean concentration of IGF-1 gradually increased from 132.85 ± 65.64 ng/ml in dogs with grade 1 tumours to 317.74 ± 119.25 ng/ml in those with grade 3 tumours, and significant differences (P < 0.05) were found among dogs with various grade tumours. These findings suggest that circulating IGF-1 may play an important role in the pathogenesis of canine mammary tumour. Moreover, high IGF-1 levels may reflect tumour cell differentiation into a more aggressive phenotype. .


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