Subjects -> ASTRONOMY (Total: 94 journals)
Showing 1 - 46 of 46 Journals sorted alphabetically
Advances in Astronomy     Open Access   (Followers: 51)
Annual Review of Astronomy and Astrophysics     Full-text available via subscription   (Followers: 39)
Annual Review of Earth and Planetary Sciences     Full-text available via subscription   (Followers: 63)
Artificial Satellites     Open Access   (Followers: 23)
Astrobiology     Hybrid Journal   (Followers: 14)
Astronomical & Astrophysical Transactions: The Journal of the Eurasian Astronomical Society     Hybrid Journal   (Followers: 6)
Astronomical Journal     Full-text available via subscription   (Followers: 8)
Astronomical Review     Open Access   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 4)
Astronomy & Geophysics     Hybrid Journal   (Followers: 48)
Astronomy and Astrophysics     Full-text available via subscription   (Followers: 60)
Astronomy and Astrophysics     Open Access   (Followers: 32)
Astronomy and Computing     Hybrid Journal   (Followers: 2)
Astronomy Letters     Hybrid Journal   (Followers: 22)
Astronomy Reports     Hybrid Journal   (Followers: 15)
Astronomy Studies Development     Open Access   (Followers: 12)
Astroparticle Physics     Hybrid Journal   (Followers: 8)
Astrophysical Bulletin     Hybrid Journal   (Followers: 3)
Astrophysical Journal     Full-text available via subscription   (Followers: 19)
Astrophysical Journal Letters     Full-text available via subscription   (Followers: 14)
Astrophysical Journal Supplement Series     Full-text available via subscription   (Followers: 14)
Astrophysics     Hybrid Journal   (Followers: 29)
Astrophysics and Space Science     Hybrid Journal   (Followers: 46)
Astrophysics and Space Sciences Transactions (ASTRA)     Open Access   (Followers: 56)
Astropolitics: The International Journal of Space Politics & Policy     Hybrid Journal   (Followers: 12)
Celestial Mechanics and Dynamical Astronomy     Hybrid Journal   (Followers: 11)
Chinese Astronomy and Astrophysics     Full-text available via subscription   (Followers: 24)
Colloid Journal     Hybrid Journal   (Followers: 3)
Comptes Rendus Physique     Full-text available via subscription   (Followers: 2)
Computational Astrophysics and Cosmology     Open Access   (Followers: 3)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 11)
Earth, Moon, and Planets     Hybrid Journal   (Followers: 55)
Earth, Planets and Space     Open Access   (Followers: 74)
EAS Publications Series     Full-text available via subscription   (Followers: 8)
EPL Europhysics Letters     Partially Free   (Followers: 8)
Experimental Astronomy     Hybrid Journal   (Followers: 39)
Expert Opinion on Astronomy and Astrophysics     Open Access   (Followers: 7)
Extreme Life, Biospeology & Astrobiology - International Journal of the Bioflux Society     Full-text available via subscription   (Followers: 6)
Few-Body Systems     Hybrid Journal   (Followers: 1)
Foundations of Physics     Hybrid Journal   (Followers: 41)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 12)
Galaxies     Open Access   (Followers: 6)
Globe, The     Full-text available via subscription   (Followers: 4)
Gravitation and Cosmology     Hybrid Journal   (Followers: 4)
Icarus     Hybrid Journal   (Followers: 75)
International Journal of Advanced Astronomy     Open Access   (Followers: 28)
International Journal of Astrobiology     Hybrid Journal   (Followers: 4)
International Journal of Astronomy     Open Access   (Followers: 19)
International Journal of Astronomy and Astrophysics     Open Access   (Followers: 29)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 13)
International Letters of Chemistry, Physics and Astronomy     Open Access   (Followers: 12)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
Journal for the History of Astronomy     Full-text available via subscription   (Followers: 19)
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Astronomical Instrumentation     Open Access   (Followers: 3)
Journal of Astronomical Telescopes, Instruments, and Systems     Hybrid Journal   (Followers: 5)
Journal of Astrophysics     Open Access   (Followers: 26)
Journal of Astrophysics and Astronomy     Open Access   (Followers: 52)
Journal of Atmospheric and Solar-Terrestrial Physics     Hybrid Journal   (Followers: 199)
Journal of Cosmology and Astroparticle Physics     Hybrid Journal   (Followers: 38)
Journal of Geophysical Research : Planets     Full-text available via subscription   (Followers: 179)
Journal of Geophysical Research : Space Physics     Full-text available via subscription   (Followers: 178)
Journal of High Energy Astrophysics     Full-text available via subscription   (Followers: 22)
Kinematics and Physics of Celestial Bodies     Hybrid Journal   (Followers: 10)
KronoScope     Hybrid Journal   (Followers: 1)
Macalester Journal of Physics and Astronomy     Open Access   (Followers: 4)
MNASSA : Monthly Notes of the Astronomical Society of South Africa     Full-text available via subscription   (Followers: 1)
Molecular Astrophysics     Full-text available via subscription   (Followers: 1)
Monthly Notices of the Royal Astronomical Society     Hybrid Journal   (Followers: 14)
Monthly Notices of the Royal Astronomical Society : Letters     Hybrid Journal  
Nature Astronomy     Hybrid Journal   (Followers: 8)
New Astronomy     Hybrid Journal   (Followers: 27)
New Astronomy Reviews     Full-text available via subscription   (Followers: 17)
Nonlinear Dynamics     Hybrid Journal   (Followers: 19)
NRIAG Journal of Astronomy and Geophysics     Open Access   (Followers: 5)
Open Astronomy     Open Access   (Followers: 2)
Physics of the Dark Universe     Open Access   (Followers: 4)
Planetary and Space Science     Hybrid Journal   (Followers: 101)
Planetary Science     Open Access   (Followers: 52)
Proceedings of the International Astronomical Union     Full-text available via subscription   (Followers: 2)
Publications of the Astronomical Society of Australia     Hybrid Journal   (Followers: 2)
Publications of the Astronomical Society of Japan     Hybrid Journal   (Followers: 3)
Publications of the Astronomical Society of the Pacific     Full-text available via subscription   (Followers: 4)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 17)
Research in Astronomy and Astrophysics     Full-text available via subscription   (Followers: 29)
Revista Mexicana de AstronomĂ­a y AstrofĂ­sica     Open Access   (Followers: 2)
Science China Physics, Mechanics & Astronomy     Hybrid Journal   (Followers: 4)
Solar Physics     Hybrid Journal   (Followers: 34)
Solar System Research     Hybrid Journal   (Followers: 14)
Space Science International     Open Access   (Followers: 192)
Space Science Reviews     Hybrid Journal   (Followers: 97)
Space Weather     Full-text available via subscription   (Followers: 24)
Transport and Aerospace Engineering     Open Access   (Followers: 13)
Universe     Open Access   (Followers: 5)
Similar Journals
Journal Cover
Earth, Moon, and Planets
Journal Prestige (SJR): 0.63
Citation Impact (citeScore): 1
Number of Followers: 55  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1573-0794 - ISSN (Online) 0167-9295
Published by Springer-Verlag Homepage  [2626 journals]
  • Revisiting Lunar Seismic Experiment Data Using the Multichannel Simulation
           with One Receiver (MSOR) Approach and Random Field Modeling
    • Abstract: Abstract Major advancements in surface wave testing over the past 2 decades have led researchers to revisit and re-analyze archived seismic records, particularly those involving measurements on the Moon. The goal of such recent efforts with lunar seismic measurements has been to gain further insights into lunar geology. We examined the active seismic data from the Apollo 16 mission for their surface wave information using a multichannel approach. The inversion of Rayleigh surface waves provided a subsurface estimate for the uppermost 8 m of the lunar subsurface with the shear wave velocities varying from 40 to 50 m/s at the surface to velocities in the range of 95–145 m/s with an average of 120 m/s at a depth of about 7 m. Generally, the results from this inversion demonstrated good agreement with previous studies. Also, we carried out numerical modeling of wave propagation in a highly-heterogeneous domain to examine the effects of such anomalous features on the acquired seismograms. Results confirmed that a sharp-contrast bi-material domain can indeed produce significant coda wave as reflected on the lunar seismic traces.
      PubDate: 2020-10-14
       
  • Automated Extraction of Crater Rims on 3D Meshes Combining Artificial
           Neural Network and Discrete Curvature Labeling
    • Abstract: Abstract One of the challenges of planetary science is the age determination of geological units on the surface of the different planetary bodies in the solar system. This serves to establish a chronology of the geological events occurring on these different bodies, hence to understand their formation and evolution processes. An approach for dating planetary surfaces relies on the analysis of the impact crater densities with size. Approaches have been proposed to automatically detect impact craters in order to facilitate the dating process. They rely on color values from images or elevation values from Digital Elevation Models (DEM). In this article, we propose a new approach for crater detection, more specifically using their rims. The craters can be characterized by a round shape that can be used as a feature. The developed method is based on an analysis of the DEM geometry, represented as a 3D mesh, followed by curvature analysis. The classification process is done with one layer perceptron. The validation of the method is performed on DEMs of Mars, acquired by a laser altimeter aboard NASA’s Mars Global Surveyor spacecraft and combined with a database of manually identified craters. The results show that the proposed approach significantly reduces the number of false negatives compared to others based on topographic information only.
      PubDate: 2020-10-08
       
  • RETRACTED ARTICLE: Aspect Sensitivity Considerations in Interpreting Radar
           Meteor Range-Spread Trail Echo Durations
    • PubDate: 2020-08-01
       
  • Study of Coronal Mass Ejections Succeeding the Associated X-Ray and
           γ-Ray Burst Solar Flares
    • Abstract: Abstract This study is dedicated to the investigation of the characteristics of CMEs following the associated X-ray and γ-ray burst solar flares. Investigated 14786 CME events and 5092 Gamma Burst Monitor (GBM) solar flare events recorded during the solar period 2008–2017, found 503 (about 10%) CME events associated with GBM post-flare events (hereafter, GBM post-flare—CME). All of these 503 events (100%) are associated with solar flares detected simultaneously in both GBM and RHESI (γ -ray solar flare possibly associated with X-ray). The associated CMEs with GBM post-flare events are wider than non-associated CME events. These results indicate that, as the flare’s flux increases, the width of the associated CME increases. The Gamma burst solar flares accelerate CMEs, but with less extent than do non-associated or associated with X-ray solar flare only events. The GBM post-flare—CME associated events have a mean speed near the solar wind average speed approximately (which is less than speed of CMEs associated with X-ray solar flares only) and faster than non-associated events. The dominant CME initial speed of the GBM post-flare—CME associated events is ~ 300 (Km/s). The CME mean mass of the GBM post-flare—CME associated events indicate that the CMEs occurred after the solar flare is on average more massive than other CMEs. Found the relationship between the mass of the GBM post-flare—CME associated events and the CME width to be on the form: (CME Mass) = − 8.6 × 10+14 + 2.9 × 10+13 × (CME width).
      PubDate: 2020-07-21
       
  • Editorial
    • PubDate: 2020-07-16
       
  • Exposure Ages, Noble Gases and Nitrogen in the Ordinary Chondrite Karimati
           (L5)
    • Abstract: Abstract Noble gas and nitrogen isotopic compositions of Karimati ordinary (L5) chondrite are presented. Aliquots of the meteorite were studied in two noble gas mass spectrometers. Its cosmic ray exposure (CRE) history, trapped noble gases and nitrogen isotopic systematic are examined. The compositions of Ne and Kr in this meteorite indicate presence of mixture of solar wind and Q trapped components. In addition to the primordial components, radiogenic 129Xe (from the decay of short-lived radioactive 129I) is observed in the two aliquots (129Xe/132Xe ranges between 1.054 and 1.311). The U/Th-4He and K-40Ar ages are discordant. U/Th-4He ages are younger than the K-40Ar ages, indicating loss of helium. The trapped N component is isotopically light analogous to Q gas/solar wind. The cosmic-ray exposure ages of the two aliquots are 16.1 ± 2.7 Ma and 16.6 ± 2.0 Ma based on the cosmogenic 21Nec and 38Arc concentrations.
      PubDate: 2020-07-13
       
  • Statistical Characteristics on SEPs, Radio-Loud CMEs, Low Frequency Type
           
    • Abstract: Abstract We have statistically analyzed a set of 115 low frequency (Deca-Hectometer wavelengths range) type II and type III bursts associated with major Solar Energetic Particle (SEP: Ep > 10 MeV) events and their solar causes such as solar flares and coronal mass ejections (CMEs) observed from 1997 to 2014. We classified them into two sets of events based on the duration of the associated solar flares:75 impulsive flares (duration < 60 min) and 40 gradual flares (duration > 60 min).On an average, the peak flux (integrated flux) of impulsive flares × 2.9 (0.32 J m−2) is stronger than that of gradual flares M6.8 (0.24 J m−2). We found that impulsive flare-associated CMEs are highly decelerated with larger initial acceleration and they achieved their peak speed at lower heights (− 27.66 m s−2 and 14.23 Ro) than the gradual flare-associated CMEs (6.26 m s−2 and 15.30 Ro), even though both sets of events have similar sky-plane speed (space speed) within LASCO field of view. The impulsive flare-associated SEP events (Rt = 989.23 min: 2.86 days) are short lived and they quickly reach their peak intensity (shorter rise time) when compared with gradual flares associated events (Rt = 1275.45 min: 3.34 days). We found a good correlation between the logarithmic peak intensity of all SEPs and properties of CMEs (space speed: cc = 0.52, SEcc = 0.083), and solar flares (log integrated flux: cc = 0.44, SEcc = 0.083). This particular result gives no clear cut distinction between flare-related and CME-related SEP events for this set of major SEP events. We derived the peak intensity, integrated intensity, duration and slope of these bursts from the radio dynamic spectra observed by Wind/WAVES. Most of the properties (peak intensity, integrated intensity and starting frequency) of DH type II bursts associated with impulsive and gradual flare events are found to be similar in magnitudes. Interestingly, we found that impulsive flare-associated DH type III bursts are longer, stronger and faster (31.30 min, 6.43 sfu and 22.49 MHz h−1) than the gradual flare- associated DH type III bursts (25.08 min, 5.85 sfu and 17.84 MHz h−1). In addition, we also found a significant correlation between the properties of SEPs and key parameters of DH type III bursts. This result shows a closer association of peak intensity of the SEPs with the properties of DH type III radio bursts than with the properties DH type II radio bursts, atleast for this set of 115 major SEP events.
      PubDate: 2020-07-11
       
  • The Subjectivity in Identification of Martian Channel Networks and Its
           Implication for Citizen Science Projects
    • Abstract: Abstract The Martian surface is incised by numerous valley networks, which indicate the planet experienced sustained widespread flowing water in the past (e.g. Carr in Water on Mars, Oxford University Press, New York, 1996; Phil Trans R Soc A 370:2193–2212, 2012. https://doi.org/10.1098/rsta.2011.0500). Examining the distribution and geometries of these valley networks provides invaluable information about the Martian climate during the period of formation. The recent advancement in high resolution images has provided an opportunity to build upon past valley maps of Mars (Bahia et al. in LPSC 2018, 2018), however, the identification of these valley networks is extremely time-consuming. A citizen science project may aid in reducing this time-consuming process; this project conducts a valley mapping task with participants of varying expertise in valley mapping to determine whether a citizen science project of this kind should be worth pursuing. This was conducted in a region adjacent to Vogel Crater (36.1° S, 10.2° W). Repeated mapping of the area (a repeatability test) found that participants with low experience in valley mapping (22 a-level physics student’s representative of the public) were inconsistent when mapping valleys. Additionally, when comparing the results of participants within this group (a reproducibility test), the majority of reproduced valleys are false positives (i.e. incorrectly traced valleys). These results were consistent with those found for the medium experience group (45 2nd year geology undergraduates). The validated tracings of the low experience group improve upon the number and total length of valleys mapped by previous studies (Hynek et al. in J Geophys Res 115:1–14, 2010). To validate these valleys requires the input of an expert to remove false positives which is less time consuming than manually mapping the images; this may indicate that a citizen science project is worth pursuing. However, to effectively identify the maximum amount of valleys an expert is required.
      PubDate: 2020-02-19
       
  • Solar Eclipses and the Surface Properties of Water
    • Abstract: Abstract During four solar eclipse events (two annular, one total and one partial) a correlation was observed between a change in water surface tension and the magnitude of the optical coverage. During one eclipse, evaporation experiments were carried out which showed a reduction in water evaporation at the same time as a rise in the surface tension. The changes did not occur on a day without a solar eclipse and are not correlated to changes in temperature, pressure, humidity of the environment. The effects are delayed by 20, 85, 30 and 37 min, respectively, compared to the maximum eclipse. Possible mechanisms responsible for this effect are presented, the most likely hypothesis being reduced water/muon interaction due to solar wind and cosmic radiation blocking during an eclipse. As an alternative hypotheses, we propose a novel neutrino/water interaction and overview of other, less likely mechanisms.
      PubDate: 2019-09-30
       
  • Dark Matter Objects: Possible New Source of Gravitational Waves
    • Abstract: Abstract Gravitational waves from mergers of black holes and neutron stars are now being detected by LIGO. Here we look at a new source of gravitational waves, i.e., a class of dark matter objects whose properties were earlier elaborated. We show that the frequency of gravitational waves and strains on the detectors from such objects (including their mergers) could be within the sensitivity range of LIGO. The gravitational waves from the possible mergers of these dark matter objects will be different from those produced by neutron star mergers in the sense that they will not be accompanied by electromagnetic radiation since dark matter does not couple with radiation.
      PubDate: 2019-09-14
       
  • Superfast Exoplanets and 9600 s
    • Abstract: Abstract Motion of a substantial part of the superfast exoplanets is found to be in the close resonance with the well-known “solar” timescale \(P_{0} \approx 0.11\) days and/or the timescale 2 \(P_0\) / \(\pi \approx 0.07\) days (at 99.9% confidence for exoplanet periods \(P < 2\) days). There is also a noticeable lack of the exoplanetary “unstable” orbits with \(P \approx 3 \pi\) \(P_0\) \(\,\approx 1.05\) days, which copies the famous “period gap” of the cataclysmic variables at \(P \approx 0.11\) days; strangely enough, the ratio of the central periods of these two gaps is equal to \(\pi ^2\) . The exoplanet phenomenon is supposed to be caused by a coherent, with the \(P_0\)  timescale, oscillation of gravity, operating within the extra-solar planetary systems.
      PubDate: 2019-07-15
       
  • Arecibo ALFA Array Observations in Search of Lunar Meteoroid-Strike EMPs
    • Abstract: Abstract We present the preliminary results of a search for transient Electromagnetic Pulses (EMP) associated with the impact of meteoroids on the lunar surface as observed with the Arecibo Observatory ALFA (Arecibo L-band Feed Array) system. The ALFA system is a cluster of seven, dual-linear polarization feeds/beams arranged in a hexagonal manner and operated in the protected L-band region centered at 1.41 GHz. We analyzed 8 TB of data totaling nearly 5.5 h of on- and off-moon observations made in February 2016. We demonstrate the observing strategy and time–frequency methods for the detection and removal of the local-radar transient interference signals while identifying potential EMPs. Local out of band radar interference signals are observed as intermodulation artifacts in the protected L-band. Seven transient wideband EMP events with time scales of less than 10 μs have been detected following the extensive vetting process we describe. Assuming that these EMP-like events originate from gram-sized meteoroid strikes and using very approximate hypervelocity impact, plasma production theory, and EMP generation theory, we estimate the progenitor impact meteoroid kinetic energy to be approximately 1.8 × 107 J. Assuming that the observed EMPs are the result of 10 g meteoroid impacts, the resultant meteoroid flux is 3 × 10−7 km−2 h−1 based solely on lunar surface area observed and net observing period. Implications of the observed transient EMP events, measured lunar noise temperature and the comparison with energy estimates derived from the existing lunar impact optical observations are also discussed.
      PubDate: 2019-05-29
       
  • Primordial Planets Predominantly of Dark Matter
    • Abstract: Abstract Cosmic structure formation is thought to occur as a bottom-up scenario, i.e. the lightest objects would have formed first. It has been suggested that the earliest structures to form could have been primordial planets. Here we propose the possibility of formation of primordial planets at high redshifts composed predominantly of dark matter (DM) particles, with planetary masses ranging from Neptune mass to asteroid mass. Most of these primordial DM planets could be free floating without being attached to a host star and a substantial fraction could be present in the halo contributing to the DM. Here we suggest that the flux of DM particles could be significantly reduced as substantial number of DM particles are now trapped in such objects, perhaps accounting for the negative results seen so far in the ongoing DM detection experiments.
      PubDate: 2019-05-17
       
  • A Catalog of Smaller Planets
    • Abstract: Abstract A compilation was made of N = 89 planets or moons for which the mass and radius are known, between the limits of 0.01 and 10 times the mass of Earth. Although starting from a larger and higher-quality (because it excludes m sin i figures) sample than that of Weiss and Marcy (Astrophys J Lett 783:L6–L12, 2014), the chart of log density versus radius confirms the WM14 results: Density increases up to about 1.5 Earth radii and decreases for larger radii, probably as the planet retains hydrogen and helium on formation.
      PubDate: 2019-05-14
       
  • Landing Area Selection Based on Closed Environment Avoidance from a Single
           Image During Optical Coarse Hazard Detection
    • Authors: Ruoyan Wei; Jianwei Jiang; Xiaogang Ruan; Jianke Li
      Pages: 73 - 104
      Abstract: Abstract The success of a landed space exploration depends largely on the final landing site, and the most important factor of landing site selection is the safety of lander, so, hazard detection and avoidance are crucial during asteroid landing. Many approaches have been proposed at present, most of them just detect hazard and select an area that is free of hazard threaten, however, in some cases, the selected site should not be the places that located in closed environment, such as the inner of crater. To tackle the issue, an approach for selecting landing site with closed environment avoidance based on a single image during optical coarse hazard detection was proposed in this paper, the approach was designed under the scheme of Chang’e-3’s landing process. The approach begins with hazard detection based on a proposed binary method. And then, for searching the candidate circular landing areas, the skeletons of areas with no hazard are taken into account, and then, control constraints are considered to select the landing areas that are accessible by the lander. Finally, the final selected circular landing area are chosen by a proposed scoring method, this method combines the factors of circular areas, including radius, the connection among circular areas, circular area’s texture and the cluster relation between circular area’s center and all the hazard. At last, serious of experiments would be conducted to test the performance of the proposed approach.
      PubDate: 2018-07-01
      DOI: 10.1007/s11038-018-9516-2
      Issue No: Vol. 121, No. 3 (2018)
       
  • Distinction in the Interplanetary Characteristics of Accelerated and
           Decelerated CMEs/Shocks
    • Authors: K. Suresh; A. Shanmugaraju; Y.-J. Moon
      Abstract: Abstract A set of 58 Coronal Mass Ejections (CMEs) with different kinematics near the sun in LASCO Field of view (FOV) is classified into two groups (i) CMEs which are accelerating (group-I) and (ii) CMEs which are decelerating (group-II). We analyze their interplanetary propagation characteristics to study the distinction between these two groups of events. Some of the following deviations are noted between the two groups as: (i) While group-II events have greater mean values of Standoff distance, Standoff time than the group-I events, the mean transit times of ICMEs and IP shocks are relatively lower for them. (ii) Group-II events are more (30%) radio-rich than the group-I (10%) and they are associated with type II solar radio burst in lower corona, (iii) The possibility of having excess magnetic energy that supports the propagation of CMEs to some extent is studied using estimated speed (VEST) and it is found that a slightly more number of events in group-I (48%) has VEST > VLASCO than group-II (33%). (iv) Net interplanetary acceleration is positive for 35% and 19% in group-I and group-II events respectively. (v) It is also found that ICME/IP shock characteristics of the two groups depend strongly on the CME acceleration.
      PubDate: 2018-12-05
      DOI: 10.1007/s11038-018-9522-4
       
  • Photometric Study of Comet C/2014 S2 (PANSTARRS) After the Perihelion
    • Authors: A. S. Betzler; O. F. de Sousa; L. B. S. Betzler
      Abstract: Abstract We analyzed the BVR photometry of comet C/2014 S2 obtained between March and June 2016, in observatories installed in Europe and the United States. Using the Lomb–Scargle periodogram, we found that the most probable periodicity deduced from the V-band magnitudes is 2.70 days, suggesting that it is the period of rotation of the nucleus of this comet is \(2.70 \pm 0.07\) days or \(68 \pm 2\) h, with a peak-to-peak light curve amplitude of \(0.4 \pm 0.1\) magnitudes. We verify that the absolute magnitude \(H_0\) and the activity index n differ from each other when they are calculated from the visual or CCD magnitudes. Considering the absolute magnitude \(H_{v0}=\) 6.0, obtained from visual magnitudes, we estimate that the lower limit of nuclear radius is 1.3 km. Analyzing the variation of magnitude R with the photometric aperture, we suggest that the coma of this object was in steady-state within the time limits of our observational interval. The coma had a mean color index B–V \(=0.79\pm 0.22\) , which is typical of active comets. Additionally, we have shown that the use of a variable photometric aperture, linked to geocentric distance, is probably unnecessary for the comet PANSTARRS .
      PubDate: 2018-11-21
      DOI: 10.1007/s11038-018-9521-5
       
  • Jerk in Planetary Systems and Rotational Dynamics, Nonlocal Motion
           Relative to Earth and Nonlocal Fluid Dynamics in Rotating Earth Frame
    • Authors: Rami Ahmad El-Nabulsi
      Abstract: Abstract Some results following from the implications of nonlocal-in-time kinetic energy approach introduced recently by Suykens in the framework of rotational dynamics and motion in a non-inertial frame are discussed. Their roles in treating aspects concerning the nonlocal motion relative to Earth, the free-fall problem, the Foucault pendulum and the motion of a massive body in a rotating tube are analyzed. Governing nonlocal equations of fluid dynamics in particular the nonlocal-in-time Navier–Stokes equations are constructed under the influence of Earth rotation. Their properties are analyzed and a number of features were revealed and discussed accordingly.
      PubDate: 2018-10-03
      DOI: 10.1007/s11038-018-9519-z
       
  • Fast Spinning of Planets
    • Authors: V. A. Kotov
      Abstract: Abstract Spin periods of Jupiter, Saturn, Uranus and Neptune are specified by the analysis of the resonant motion of large satellites: \(P = 0.445(2)\,\hbox {d}\) , 0.448(1) d, 0.673(9) d and 0.561(7) d, respectively. They occur to be near-commensurate with \(P_0=9600.606(12)\,\hbox {s}\) , the period of the “cosmic” oscillation, discovered first in the Sun, then in other variable objects of the Universe. The like analysis of spin rates of the total set of the largest and fastest rotators of the Solar system (with mean diameters \(\ge 500\,\hbox {km}\) and \(P < 2\,\hbox {d}\) ,—of planets, asteroids and satellites) resulted in the best commensurable, or “synchronizing”, timescale 9594(65) s, coinciding fairly well with \(P_0\) too (the probability that the two timescales could agree by chance, is less than \(10^{-5}\) ). True origin of this odd common resonance of our planetary system is unknown.
      PubDate: 2018-09-29
      DOI: 10.1007/s11038-018-9520-6
       
  • The Temperature Regime of the Proposed Landing Sites for the Luna-Glob
           Mission in the South Polar Region of the Moon
    • Authors: E. A. Feoktistova; S. G. Pugacheva; V. V. Shevchenko
      Abstract: Abstract In this paper, we investigated the possibility of existence of the hydrogen-containing volatile compounds, similar to those found in the Cabeus crater, in the area of the proposed landing ellipses of the Luna-Glob mission. We found that the existence of water ice and other hydrogen-containing substances is possible only in the presence of a shielding layer of regolith. The time of existence of such deposits does not exceed several tens or hundreds years for a layer of regolith with a thickness of 0.4 m and several thousand years for a layer of regolith 1 m thick.
      PubDate: 2018-08-10
      DOI: 10.1007/s11038-018-9518-0
       
 
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