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  • Predictive model linking super-rotation, magnetospheric generation and atmospheric heating
    Open Astron. (IF 0.831) Pub Date : 2020-12-31
    Jonathan Peter Merrison

    This work applies a previously suggested model of gravitational field propagation to various planetary bodies within the solar system. Primarily the goal has been to critically test the validity of this model by identifying observations which are in direct conflict with it. Specifically this model predicts a Doppler shift in gravitational acceleration (gD). Applying the model to the planets and the

    更新日期:2021-01-11
  • Evolution of space debris for spacecraft in the Sun-synchronous orbit
    Open Astron. (IF 0.831) Pub Date : 2020-12-28
    Yu Jiang; Hengnian Li; Yue Yang

    In this paper, the evolution of space debris for spacecraft in the Sun-Synchronous orbit has been investigated. The impact motion, the evolution of debris from the Sun-Synchronous orbit, as well as the evolution of debris clouds from the quasi-Sun-Synchronous orbit have been studied. The formulas to calculate the evolution of debris objects have been derived. The relative relationships of the velocity

    更新日期:2020-12-30
  • How has Lunar science developed? A bibliometric analysis and systematic review
    Open Astron. (IF 0.831) Pub Date : 2020-12-31
    Jiao Wang; Yaoyao Chen; Guangyu Liu; Weiming Cheng; Tong Yin

    Lunar exploration is a significant process to unravel the evolutionary history of the Earth-Moon system and the pivotal foundation for the exploration of the solar system. A total of 49,161 articles recorded in a comprehensive online literature database between 1959 and 2018 were reviewed to address the development of lunar science in six aspects: publication output volume, keywords, journals, authorship

    更新日期:2020-12-27
  • Evaluating the effect of four unknown parameters included in a latitudinal energy balance model on the habitability of exoplanets
    Open Astron. (IF 0.831) Pub Date : 2020-12-31
    Majid Bahraminasr; S. Javad Jafarzadeh; Fatemeh Montazeri; Atila Poro; Soroush Sarabi

    Among different models for determining the habitable zone (HZ) around a star, a Latitudinal Energy Balance Model (LEBM) is very beneficial due to its parametricity which keeps a good balance between complexity and simulation time. This flexibility makes the LEBM an excellent tool to assess the impact of some key physical parameters on the temperature and the habitability of a planet. Among different

    更新日期:2020-12-27
  • The non-Fourier image reconstruction method for the STIX instrument
    Open Astron. (IF 0.831) Pub Date : 2020-12-31
    Marek Siarkowski; Tomasz Mrozek; Janusz Sylwester; Michalina Litwicka; Magdalena Dąbek

    In this work we aimed to develop the image reconstruction algorithm without any analytical simplifications and restrictions. In our method we abandon Fourier’s approach to image reconstruction, and instead use the number of counts recorded in each detector pixel, and then reconstruct each image using a classical Richardson-Lucy algorithm. Among similar works performed in the past, our approach is based

    更新日期:2020-12-27
  • Spectral Properties of Fermi Blazars and their Unification Schemes
    Open Astron. (IF 0.831) Pub Date : 2020-12-02
    Evaristus U. Iyida; Finbarr C. Odo; Augustine E. Chukwude; Augustine A. Ubachukwu

    We use the distributions of spectral indices (αv ) of a large homogenous sample of Fermi-detected blazars to re-investigate the relationship between flat spectrum radio quasars (FSRQs) and subclasses of BL Lac objects (BL Lacs). We compute the broadband synchrotron and Compton spectral indices from radio-to-X-ray and X-ray to y-ray bands, respectively. Analyses of our data show continuity in the distributions

    更新日期:2020-12-03
  • Re-entry prediction of objects with low-eccentricity orbits based on mean ballistic coefficients
    Open Astron. (IF 0.831) Pub Date : 2020-11-22
    Zhang Wei; Cui Wen; Wang Xiuhong; Wei Dong; Liu Xing

    During re-entry objects with low-eccentricity orbits traverse a large portion of the dense atmospheric region almost every orbital revolution. Their perigee decays slowly, but the apogee decays rapidly. Because ballistic coefficients change with altitude, re-entry predictions of objects in low-eccentricity orbits are more difficult than objects in nearly circular orbits. Problems in orbit determination

    更新日期:2020-11-27
  • Mars: Life, Subglacial Oceans, Abiogenic Photosynthesis, Seasonal Increases and Replenishment of Atmospheric Oxygen
    Open Astron. (IF 0.831) Pub Date : 2020-11-04
    Rhawn G. Joseph; Natalia S. Duxbury; Giora J. Kidron; Carl H. Gibson; Rudolph Schild

    The discovery and subsequent investigations of atmospheric oxygen on Mars are reviewed. Free oxygen is a biomarker produced by photosynthesizing organisms. Oxygen is reactive and on Mars may be destroyed in 10 years and is continually replenished. Diurnal and spring/summer increases in oxygen have been documented, and these variations parallel biologically induced fluctuations on Earth. Data from the

    更新日期:2020-11-06
  • Observational data and orbits of the asteroids discovered at the Baldone Observatory in 2015–2018
    Open Astron. (IF 0.831) Pub Date : 2020-10-22
    Ireneusz Wlodarczyk; Kazimieras Černis; Ilgmars Eglitis

    This paper is devoted to the discovery of 37 asteroids at the Baldone Astrophysical Observatory (MPC 069) from 2015 to 2018, and one of dynamically interesting Mars-crosser (MC) observed at the Baldone Astrophysical Observatory, namely 2008 LX16. In Baldone Observatory, was independently discovered the Near-Earth Object 2018 GE3 on the image of 13 April 2018. Also, the NEO 2006 VB14 was observed doing

    更新日期:2020-10-28
  • Effects of Solar Activity on Ionospheric Ion Upflow During Geomagnetic Quiet Periods: DMSP Observations
    Open Astron. (IF 0.831) Pub Date : 2020-10-15
    Shuai Fu; Yong Jiang; Xiaoping Zhang

    Based on the Defense Meteorological Satellite Program (DMSP) observations during Solar Cycle 23, this paper examines solar activity dependence of ionospheric bulk ion upflow events (IUEs) in the Southern Hemisphere (SH). Much previous similar work was conducted over the Northern Hemisphere (NH) with measurements from European Incoherent Scatter (EISCAT). To eliminate the influence of geomagnetic disturbance

    更新日期:2020-10-19
  • Seeding the Solar System with Life: Mars, Venus, Earth, Moon, Protoplanets
    Open Astron. (IF 0.831) Pub Date : 2020-10-17
    Rhawn G. Joseph; Olivier Planchon; Carl H. Gibson; Rudolph Schild

    In the space of the entire universe, the only conclusive evidence of life, is found on Earth. Although the ultimate source of all life is unknown, many investigators believe Earth, Mars, and Venus may have been seeded with life when these planets, and the sun, were forming in a galactic cluster of thousands of stars and protoplanets. Yet others hypothesize that while and after becoming established

    更新日期:2020-10-19
  • A new method to identify the mass parameters of spacecraft
    Open Astron. (IF 0.831) Pub Date : 2020-10-01
    Dongbo Meng; Xia Li; Jianguo Pang; Jianxin Lu

    A two-step identification method is proposed, both the moment of inertia and the mass properties are identified. A new index parameter which is different from the commonly used condition number is first defined for designing the optimal excitation. A method is introduced based on the least squares algorithm. Detailed mathematical equations and numerical analysis are proposed. Simulation results show

    更新日期:2020-10-02
  • Electromagnetic-launch-based method for cost-efficient space debris removal
    Open Astron. (IF 0.831) Pub Date : 2020-09-18
    Chongyuan Hou; Yuan Yang; Yikang Yang; Kaizhong Yang; Xiao Zhang; Junyong Lu

    The increase in space debris orbiting Earth is a critical problem for future space missions. Space debris removal has thus become an area of interest, and significant research progress is being made in this field. However, the exorbitant cost of space debris removal missions is a major concern for commercial space companies. We therefore propose the debris removal using electromagnetic launcher (DREL)

    更新日期:2020-09-21
  • Bianchi type–I Model with Time Varying Λ and G: The Generalized Solution
    Open Astron. (IF 0.831) Pub Date : 2020-09-11
    Alnadhief H. A. Alfedeel

    In this paper, we have investigated the homogeneous and anisotropic Bianchi type–I cosmological model with a time-varying Newtonian and cosmological constant. We have analytically solved Einstein’s field equations (EFEs) in the presence of a stiff-perfect fluid. We show that the analytical solution for the average scale factor for the generalized Friedman equation involves the hyper-geometric function

    更新日期:2020-09-15
  • Some kinematics of halo coronal mass ejections
    Open Astron. (IF 0.831) Pub Date : 2020-08-28
    Virendra Kumar Verma; Nishant Mittal; Ramesh Chandra

    We present an investigation of halo coronal mass ejections (HCMEs) kinematics and other facts about the HCMEs. The study of HCMEs is very important because HCMEs are regarded as the main causes of heliospheric and geomagnetic disturbances. In this study, we have investigated 313 HCMEs observed during 1996-2012 by LASCO, coronal holes, and solar flares. We find that HCMEs are of two types: accelerated

    更新日期:2020-08-31
  • New Data on the Eclipsing Binary V1848 Ori and Improved Orbital and Light Curve Solutions
    Open Astron. (IF 0.831) Pub Date : 2020-08-03
    Fatemeh Davoudi; Atila Poro; Fahri Alicavus; Afshin Halavati; Saeed Doostmohammadi; AmirAbbas Shahdadi; Sareh Vahedi; Arman Pishahang; Maryam Zare; Milad Jamali; AmirMohammad Salajeghe; Faezeh Jahediparizi; Hassan Ashta; Seyed Mohsen Shojaatalhosseini

    New observations of the eclipsing binary system V1848 Ori were carried out using the V filter resulting in a determination of new times of minima and new ephemeris were obtained. We presented the first complete analysis of the system’s orbital period behavior and analysis of O-C diagram done by the GA and MCMC approaches in OCFit code. The O-C diagram demonstrates a sinusoidal trend in the data; this

    更新日期:2020-08-06
  • The dynamical environment of the primary in the triple asteroid (45) Eugenia
    Open Astron. (IF 0.831) Pub Date : 2020-07-22
    Min Jiang; Qingtian Ma

    We investigated the dynamical behavior in the potential of the primary in the triple asteroid (45) Eugenia with the calculation of the full gravitational potential caused by its 3D irregular shape. We presented the whole structure of the gravitational potential and the effective potential of (45) Eugenia in the coordinate planes, and showed the surface height, surface gravitational force accelerations

    更新日期:2020-07-27
  • Two-dimensional correlation analysis of periodicity in active galactic nuclei time series
    Open Astron. (IF 0.831) Pub Date : 2020-07-22
    Andjelka B. Kovačević; Luka Č. Popović; Dragana Ilić

    The active galactic nuclei (AGN) are among the most powerful sources with an inherent, pronounced and random variation of brightness. The randomness of their time series is so subtle as to blur the border between aperiodic fluctuations and noisy oscillations. This poses challenges to analysing of such time series because neither visual inspection nor pre-exisitng methods can identify well oscillatory

    更新日期:2020-07-27
  • Does Hawking predict the correct temperature of a black-hole?
    Open Astron. (IF 0.831) Pub Date : 2020-07-13
    Kapil Chandra

    In our study of the validity of Hawking’s predicted radiation temperature of a black-hole, we found that the calculated temperature is another form of Zeldovich’s expression for the cosmological constant. We reasoned that as Zeldovich predicted the extreme value of cosmological constant thus Hawking might have also predicted an extreme temperature. However, the actual temperature might be something

    更新日期:2020-07-14
  • On the role of collisions with meteoroids in splitting and acceleration of heliocentric velocity of comets
    Open Astron. (IF 0.831) Pub Date : 2020-06-27
    Ayyub Guliyev; Rustam Guliyev

    The hypothesis on the role of the meteoroid impacts in the comet nuclei splitting as well as acceleration of their heliocentric velocity are considered. Inclinations of the orbits of split comets relative to the movement planes of 100 known meteoroid streams are calculated. The analysis is carried out for the cases: when the cometary nodes are located from the meteoroids orbit < 0.1 AU; MOID-values

    更新日期:2020-06-29
  • Planck Neutrinos as Ultra High Energy Cosmic Rays
    Open Astron. (IF 0.831) Pub Date : 2020-06-24
    Dmitri L. Khokhlov

    The studied conjecture is that ultra high energy cosmic rays (UHECRs) are hypothetical Planck neutrinos arising in the decay of the protons falling onto the gravastar. The proton is assumed to decay at the Planck scale into positron and four Planck neutrinos. The supermassive black holes inside active galactic nuclei, while interpreted as gravastars, are considered as UHECR sources. The scattering

    更新日期:2020-06-24
  • The temperature model of the thermal re-radiation model in multilayer insulation systems
    Open Astron. (IF 0.831) Pub Date : 2020-06-05
    Wenhui Cui; Zhenyu Sun; Jian Yang

    In this manuscript, the temperature model of multilayer insulation (MLI) on a spacecraft solar panel in thermal radiation is considered. The thermal insulation performance of MLI and the stress of the spacecraft are also considered. The thermal equilibrium equation of the surface temperature of MLI spacecraft in the presence of current transfer, and the iterative temperature acquisition algorithm of

    更新日期:2020-06-05
  • New evidence of the Suess/de Vries cycle existing in historical naked-eye observations of sunspots
    Open Astron. (IF 0.831) Pub Date : 2020-05-20
    Lihua Ma; José M. Vaquero

    Solar activity affects geophysical and heliophysical processes. Long-term changes in solar activity are closely related to climate change. Solar physicists and earth science researchers need longer observations of solar activity. Current continuous observations of solar activity are only about 400 years. Some scholars have compiled naked-eye observations of sunspots from 200 BC to 1918 AD from historical

    更新日期:2020-05-20
  • Asymmetry between galaxies with different spin patterns: A comparison between COSMOS, SDSS, and Pan-STARRS
    Open Astron. (IF 0.831) Pub Date : 2020-05-13
    Lior Shamir

    Previous observations of a large number of galaxies show differences between the photometry of spiral galaxies with clockwise spin patterns and spiral galaxies with counterclockwise spin patterns. In this study the mean magnitude of a large number of clockwise galaxies is compared to the mean magnitude of a large number of counterclockwise galaxies. The observed difference between clockwise and counterclockwise

    更新日期:2020-05-13
  • Broad spectral lines in AGNs and supermassive black hole mass measurements
    Open Astron. (IF 0.831) Pub Date : 2020-05-13
    Luka Č. Popović

    The mass measurement of supermassive black holes (SMBHs) is a very complex task. Between several methods for SMBH mass measurements, some of them use the spectral lines, which indicate the motion of the emitting/absorbing material around an SMBH. Mostly, there is an assumption of virialization of line emitting gas in the region which is close to the central SMBH. In this paper we will give an overview

    更新日期:2020-05-13
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