N. P. Pitjev

Saint Petersburg State University | SPBU · Department of Astronomy

The estimate of the change rate of the solar gravitational parameter $\mathrm{d}(GM_{\odot})/\mathrm{d}t$ is obtained from processing modern positional observations of planets and spacecraft. Observations were processed and parameters were determined basing on the numerical planetary ephemeris EPM2019. The obtained annual decrease in solar mass $M_...

The estimate of the change rate of the solar gravitational parameter d( GM ⊙ )∕d t is obtained from processing modern positional observations of planets and spacecraft. Observations were processed and parameters were determined basing on the numerical planetary ephemeris EPM2019. The obtained annual decrease in solar mass M ⊙ accounts for the loss...

The possibility of obtaining dynamical estimates of the total masses in the two Trojan asteroid groups of Jupiter is investigated. The compact Greek (L4) and Trojan (L5) groups contain several tens of thousands of asteroids near the stable Lagrange points moving in a 1: 1 resonance with the orbital motion of Jupiter. The dynamical mass estimates $$...

The Kuiper belt includes tens of thousand of large bodies and millions of smaller objects. The main part of the belt objects is located in the annular zone between 39.4 and 47.8 au from the Sun; the boundaries correspond to the average distances for orbital resonances 3:2 and 2:1 with the motion of Neptune. One-dimensional, two-dimensional, and dis...

Dynamicalmass estimates for the main asteroid belt and the trans-Neptunian Kuiper belt have been found from their gravitational influence on the motion of planets. Discrete rotating models consisting ofmovingmaterial points have been used tomodel the total attraction fromsmall or as yet undetected bodies of the belts. The masses of the model belts...

Lunar and planetary observations of different types are discussed for the time span 1717–1982. The modern ranging observations and the historical ones (mainly transits of Mercury and Venus, solar eclipses and occultations of the inner planets by the Moon) are treated separately and some attempts to detect relativistic effects are carried out. From...

The theory of the motion of Mercury, Venus, Earth and Mars is constructed by numerical integration. The theory takes into account relativistic corrections in the frame of Schwarzschild's space-time metrics. The constants of the theory are determined by discussion of the Soviet and American radar observations of Mercury, Venus and Mars, position ast...

As part of a reorganization of the International Astronomical Union (IAU), Commission 4 (Ephemerides) went out of existence after the IAU General Assembly in August 2015. This paper presents brief discussions of some of the developments in fundamental astronomy that have influenced and been influenced by the work of Commission 4 over its 96-year hi...

The history of estimation of the heliocentric gravitational constant is given. Initially the value of GM ⊙ was based on the mean period of motion of the Earth around the Sun, then on estimation of the value of the astronomical unit, and finally the modern value of GM ⊙ is determined with the extraordinarily high accuracy, GM ⊙ = 132 712 440 042 ± 1...

An estimation of the mass of the main asteroid belt was made on the basis of the new version of EPM2014 ephemerides of the Institute of Applied Astronomy of Russian Academy of Sciences using about 800000 positional observations of planets and spacecraft. We obtained the individual estimations of masses of large asteroids from radar data, as well as...

The IAU Commission 4 Working Group on Standardizing Access to Ephemerides recommends the use of the Spacecraft and Planet Kernel (SPK) format to provide a uniform format for the position ephemerides of planets and other natural solar system bodies, and the use of the Planetary Constants Kernel (PCK) for the orientation of these bodies. These format...

Commission 4 was among the first set of commissions formed within the IAU at its founding in 1919. (Commissions were originally called “Standing Committees.”) During its 96 years of service to the IAU and astronomical community in general, the commission has been fortunate to have been led by many distinguished scientists — see the list of presiden...

The IAU Commission 4 Working Group on Standardizing Access to Ephemerides recommends the use of the Spacecraft and Planet Kernel (SPK) format as a standard format for the position ephemerides of planets and other natural solar system bodies, and the use of the Planetary Constants Kernel (PCK) format for the orientation of these bodies. It further r...

This paper outlines the progress in development of the numerical planet ephemerides EPM-Ephemerides of Planets and the Moon. EPM was first created in the 1970s in support of Russian space flight missions and constantly improved at IAA RAS. Comparison between various available EPM ephemerides (EPM2004, EPM2008, EPM2011) is shown. The first results o...

The EPM (Ephemerides of Planets and the Moon) numerical ephemerides were first created in the 1970s in support of Russian space flight missions and since then have been constantly improved at IAA RAS. In the following work, the latest version of the planetary part of the EPM2011 numerical ephemerides is presented. The EPM2011 ephemerides are comput...

The triennial meeting of Commission 4 was attended by 16 people. All of the presentations from the meeting are provided on the commission website at http://www.iaucom4.org/c4docs.html , so this report provides only summaries.

We have searched for and estimated the possible gravitational influence of dark matter in the Solar system based on the EPM2011 planetary ephemerides using about 677 thousand positional observations of planets and spacecraft. Most of the observations belong to present-day ranging measurements. Our estimates of the dark matter density and mass at va...

The high precision of the latest version of the planetary ephemeris Ephemerides of the Planets and the Moon (EPM2011) enables one to explore more accurately a variety of small effects in the Solar system. The processing of about 678 thousand of position observations of planets and spacecraft for 1913–2011 with the predominance of modern radar measu...

The asteroid Apophis is one of the most hazardous near-Earth asteroids. As a result of the scattering of Apophis’ potential trajectories after its close approach in 2029, and its possible approach in 2036, there are many dangerous trajectories including impact trajectories after 2036. The purpose of this study is to identify and investigate these t...

More than 635 thousand positional observations of planets and spacecraft of various types (mostly radiotechnical ones, 1961–2010) were used to estimate possible changes in the gravitational constant, Sun’s mass, and semi-major axes of planetary orbits, as well as the associated value of the astronomical unit. The observations were analyzed based on...

The analysis of the observational data for the secular perihelion precession of Mercury, Earth, and Mars, based on the EPM2004 ephemerides, results in new upper limits on density of dark matter in the solar system.

The Commission 4 Organizing Committee began its work for the 2009-2012 triennium by revising the commission's terms of reference, which serve as our “mission statement.” The new terms of reference are: (a)Maintain cooperation and collaboration between the national offices providing ephemerides, prediction of phenomena, astronomical reference data,...

In the 2006–2009 triennium, the International Astronomical Union (IAU) Working Group on Numerical Standards for Fundamental Astronomy determined a list of Current Best Estimates (CBEs). The IAU 2009 Resolution B2 adopted these CBEs as the IAU (2009) System of Astronomical Constants. Additional work continues to define the process of updating the CB...

More than 635 000 positional observations (mostly radiotechnical) of planets and spacecraft (1961-2010), have been used for estimating possible changes of the gravitation constant, the solar mass, and semi-major axes of planets, as well as the value of the astronomical unit, related to them. The analysis of the observations has been performed on th...

The Apophis asteroid attracted the attention of scientists immediately after its discovery in 2004, because the initially determined orbit of this asteroid assumes a possible collision with Earth in April 2029. The size of Apophis is about several hundred meters, and its collision with Earth might result in a large regional or even global catastrop...

The current state of the last version of the planet part of EPM's ephemerides of IAA RAS (EPM2010) integrated in the PPN metric over the 1800 -2200 time interval is presented. The updated dynamical model includes perturbations from all Trans-Neptunian Objects at the mean distance of 43 AU in addition to the perturbations from the major planets, the...

The IAU Working Group (WG) on Numerical Standards for Fundamental Astronomy has been tasked with updating the IAU Current Best Estimates (CBEs), conforming with the IAU Resolutions, IERS Conventions and Système International d'Unités whenever possible. As part of its effort to achieve this, the WG is working in close cooperation with IAU Commission...

JPL planetary ephemeris development has been very active assimilating measurements from current planetary missions and supporting future missions. The NASA Mars Science Laboratory (MSL) mission with launch in 2009 requires knowledge of the Earth and Mars ephemerides with 30m accuracy. By comparison, the accuracy of the Mars ephemeris in the widely...

Perturbations from asteroids and Trans-Neptunian Objects affect significantly on the orbits of planets and should be taken into account when high-accuracy planetary ephemerides are constructed. On the other hand, from an analysis of motion of the major planets by processing of precise measurements of spacecraft a limitation on the total TNO mass ma...

This note suggests nomenclature for dealing with the units of various astronomical quantities that are used with the relativistic time scales TT, TDB, TCB and TCG. It is suggested to avoid wordings like "TDB units" and "TT units" and avoid contrasting them to "SI units". The quantities intended for use with TCG, TCB, TT or TDB should be called "TCG...

We propose to the NSFA (the IAU Working Group on Numerical Standards for Fundamental Astronomy) the following representative values and realistic uncertainties for the masses of the three largest asteroids (Ceres, Pallas, Vesta), to be used as the current best estimates: $$\begin{array}{ll}M_{\rm Ceres}/M_\odot \,=\, 4.72(3)\cdot 10^{-10},\\ M_{\rm...

In the seventies of the last century the EPM ephemerides (Ephemerides of Planets and the Moon) of IAA RAS originated and have been developed since that time. These ephemerides are based upon relativistic equations of motion of celestial bodies and light rays and upon relativistic time scales. The updated model of EPM2008 includes the new values of...

The analysis of the observational data for the secular perihelion precession of Mercury, Earth, and Mars, based on the EPM2004 ephemerides, results in new upper limits on density of dark matter in the solar system.

Different types of radiometric observations of planets and spacecraft, as well as optical data used for constructing modern high-precision planet ephemerides are presented. New mass values for planets and asteroids are given. The IAA RAS EPM ephemerides (Ephemerides of Planets and the Moon) are the basis for the Russian “Astronomical Yearbook” and...

At the 2006 International Astronomical Union (IAU) General Assembly (GA), a proposal was adopted to form the Working Group (WG) for Numerical Standards of Fundamental Astronomy. The goal of the WG are to update "IAU Current Best Estimates" conforming with IAU Resolutions, the International Earth Rotation and Reference System Service (IERS) Conventi...

We discuss the dynamical model of the planet motions and EPM ephemerides.

We discuss the present state of the art of the solar quadrupole moment from planetary ephemerides.

A code for constructing self-gravitating galactic models in a given potential by Schwarszchild's method was developed. As an example a distribution function for a two-component model of the Galactic potential by Kutuzov and Ossipkov was found.

Over the next decade the gravitational physics community will benefit from dramatic improvements in many technologies critical to the tests of gravity and gravitational-wave detection. The highly accurate deep space navigation, interplanetary laser ranging and communication, interferometry and metrology, high precision frequency standards, precise...

The accomplishments of space flights and introduction of new astrometric methods (radar ranging, lunar laser-ranging, VLBI measurements) in the 1960s required considerably more precise planetary ephemerides than it was possible with classical analytical theories by Leverrier, Hill, Newcomb and Clemence. On the other hand, these modern data made pos...

The latest version of the planetary part of the numerical ephemerides EPM (Ephemerides of Planets and the Moon) developed at the Institute of Applied Astronomy of the Russian Academy of Sciences is presented. The ephemerides of planets and the Moon were constructed by numerical integration in the post-Newtonian metric over a 140-year interval (from...

We used more than 250 000 high-precision American and Russian radar observations of the inner planets and spacecraft obtained in the period 1961–2003 to test the relativistic parameters and to estimate the solar oblateness. Our analysis of the observations was based on the EPM ephemerides of the Institute of Applied Astronomy, Russian Academy of Sc...

The total mass of the asteroid belt is estimated from an analysis of the motions of the major planets by processing high precision measurements of ranging to the landers Viking-1, Viking-2, and Pathfinder (1976–1997). Modeling of the perturbing accelerations of the major planets accounts for individual contributions of 300 minor planets; the total...

The changes in the structure of the field of motion directions when we vary the integral of energy in 2D potentials of Contopoulos and Henon-Heiles are studied. The complication of this structure (the grow of multiplicity of the field and the following stochastization) in the vicinities of the unstable periodic orbits are observed. The folds of the...

The JPL planetary and lunar ephemerides – DE200/LE200, DE403/LE403, DE405/LE405 and the planetary and lunar ephemerides, EPM87, EPM98, and EPM2000, constructed in the Institute of Applied Astronomy of RAS are described. Common properties and differences of the various ephemerides are given. Graphical comparisons of the DE ephemerides with each othe...

Modern radiometric observations of planets, beginning in 1961, make it possible to determine and improve a broad set of astronomical constants from the value of the astronomical unit (AU) to parameters of PPN formalism. Three main factors that influence the progress in the determination of astronomical constants - 1) reductions of the observational...

A numerical theory of motion of the inner planets and Jupiter is presented. The numerical ephemerides were compared with the set of American and Russian radar observations of planets, obtained during 1961–1995 (nearly 60000 observations), together with range measurements of Martian landers Viking-1,-2 and Mariner-9 tracking data. The main fitted pa...

A numerical theory of motion of the inner planets and Jupiter is presented. The numerical ephemerides were compared with the set of American and Russian radar observations of planets, obtained during 1961–1995 (nearly 60000 observations), together with range measurements of Martian landers Viking-1,-2 and Mariner-9 tracking data. The main fitted pa...

An analytical expression for a third integral of motion in an rotationally symmetric potential is derived. This expression is constant along trajectories.

The new analysis of radar observations of inner planets for the time span 1964–1989 is described. The residuals show that Mercury topography is an important source of systematic errors which have not been taken into account up to now. The longitudinal and latitudinal variations of heights of Mercury surface were found and an approximate map of equa...

Modern planetary theory may be considred as a carrier of 4-dimensianal dynamical reference frame which is to be canfronted with stellar (or quasar) based fundamental frame. Of most interest is the problem of existence of secular trends between the above systems. We investigated the problem by discussing a vast set of planetary observations of diffe...

The theory of the motion of Mercury, Venus, Earth and Mars is constructed by numerical integration. The theory takes into account relativistic corrections in the frame of Schwarzschild's space-time metrics. The theory presented is an ephemeris base for deep space experiments.

More recent planet ephemerides constructed at JPL, IAA RAS and IMCCE, their sim-ilarities, differences and solution parameters are considered. Data residuals for EPM2006 (IAA RAS ephemerides) are given. New values of planet and asteroid masses and Astronomical Unit are presented.

The IAU Working Group (WG) on Numerical Standards for Fundamental Astronomy has been tasked with updating the IAU Current Best Estimates (CBEs). In addition to the need to update the CBEs because of improved estimates, there have also been significant changes that impact the IAU CBEs. Since the IAU CBEs were adopted, the IERS Conventions 2003, a do...

This volume contains the descriptions of algorithms used in 'Astronomical Yearbook'. Moreover, new modern theories of motion of the sun, the moon, and the major planets, classical and relativistic time scales used in ephemeris astronomy, precession-nutation models and new concept of the Celestial Ephemeris Origin (CEO) are also presented. 47 numeri...