Tables of Libration-Point Parameters for Selected Solar System Objects

2001 ◽  
Vol 49 (1) ◽  
pp. 197-217
Author(s):  
David W. Dunham ◽  
Daniel P. Muhonen
Keyword(s):  
Solar System ◽  
Libration Point ◽  
Solar System Objects

scholarly journals Astrometry of the solar system: the ground-based observations

2007 ◽  
Vol 3 (S248) ◽  
pp. 66-73
Author(s):  
J.-E. Arlot
Keyword(s):  
Solar System ◽  
Space Missions ◽  
Physical Characteristics ◽  
Physical Parameters ◽  
Dynamical Models ◽  
Long Period ◽  
Solar System Objects ◽  
Different Characteristics

AbstractThe main goal of the astrometry of solar system objects is to build dynamical models of their motions to understand their evolution, to determine physical parameters and to build accurate ephemerides for the preparation and the exploitation of space missions. For many objects, the ground-based observations are still very important because radar or observations from space probes are not available. More, the need of observations on a long period of time makes the ground-based observations necessary. The solar system objects have very different characteristics and the increase of the astrometric accuracy will depend on the objects and on their physical characteristics. The purpose of this communication is to show how to get the best astrometric accuracy.

scholarly journals A Photometric Study of Regolith Intimate Mixing with Ice-Like Impurity

2021 ◽  
Author(s):  
Dwaipayan Deb ◽  
Pavan Chakraborty
Keyword(s):  
Solar System ◽  
Linear Trend ◽  
Geological Processes ◽  
Solar System Objects ◽  
Shadowing Effect ◽  
Mixing Proportion ◽  
In Situ Observations ◽  
End Members ◽  
Reflectance Data

Abstract Surfaces of solid solar system objects are covered by layers of particulate materials called regolith originated from their surface bedrock. They preserve important information about surface geological processes. Often regolith is composed of more than one type of particle in terms of composition, maturity, size, etc. Experiments and theoretical works are being carried out to constrain the result of mixing and extract the abundance of compositional end-members from regolith spectra. In this work we have studied, photometric light scattering from simulated surfaces made of two different materials – one is highly bright quartz particles ≈ 80µm and the other moderately bright sandstone particles ≈ 250µm. The samples were mixed with varying proportions and investigated at normal illumination conditions to avoid the shadowing effect. Said combinations may resemble ice mixed regolith on various solar system objects and therefore important for in situ observations. We find that the combinations show a linear trend in the corresponding reflectance data in terms of their mixing proportion and some interesting facts come out when compared to previous studies.

scholarly journals Prediction of stellar occultations by distant solar system bodies in the Gaia era

2017 ◽  
Vol 12 (S330) ◽  
pp. 382-385
Author(s):  
Josselin Desmars ◽  
Julio Camargo ◽  
Bruno Sicardy ◽  
Felipe Braga-Ribas ◽  
Roberto Vieira-Martins ◽  
...  
Keyword(s):  
Solar System ◽  
Orbit Determination ◽  
Proper Motions ◽  
Close Vicinity ◽  
Gaia Dr1 ◽  
Solar System Objects ◽  
Stellar Occultations ◽  
Solar System Bodies ◽  
Transneptunian Objects ◽  
Gaia Dr2

AbstractStellar occultations are a unique technique to access physical characteristics of distant solar system objects from the ground. They allow the measure of the size and the shape at kilometric level, the detection of tenuous atmospheres (few nanobars), and the investigation of close vicinity (satellites, rings) of Transneptunian objects and Centaurs. This technique is made successful thanks to accurate predictions of occultations. Accuracy of the predictions depends on the uncertainty in the position of the occulted star and the object's orbit. The Gaia stellar catalogue (Gaia Collaboration (2017)) now allows to get accurate astrometric stellar positions (to the mas level). The main uncertainty remains on the orbit. In this context, we now take advantage of the NIMA method (Desmars et al.(2015)) for the orbit determination and of the Gaia DR1 catalogue for the astrometry. In this document, we show how the orbit determination is improved by reducing current and some past observations with Gaia DR1. Moreover, we also use more than 45 past positive occultations observed in the 2009-2017 period to derive very accurate astrometric positions only depending on the position of the occulted stars (about few mas with Gaia DR1). We use the case of (10199) Chariklo as an illustration. The main limitation lies in the imprecision of the proper motions which is going to be solved by the Gaia DR2 release.

scholarly journals Are interstellar ices porous, and how do the pores collapse?

2015 ◽  
Vol 11 (A29A) ◽  
Author(s):  
C. R. Hill ◽  
C. Mitterdorfer ◽  
T. G. A. Youngs ◽  
D. T. Bowron ◽  
N. Pascual ◽  
...  
Keyword(s):  
Solar System ◽  
Amorphous Solid ◽  
Growth Conditions ◽  
Molecular Gas ◽  
Pore Collapse ◽  
Star Forming ◽  
Gas Phases ◽  
Star Forming Regions ◽  
Solar System Objects ◽  
Interstellar Ices

Amorphous solid water (ASW) is of great importance in astrochemistry as it has been detected in star forming regions, comets, and cold solar-system objects. A key property of ASW is its porous nature (with the extent of porosity reflecting the formation and growth conditions) and the subsequent pore collapse when the ice is heated. If interstellar ices are porous there are huge implications to both the process of planet formation and the budgets of molecular gas in the solid and gas phases. It is therefore vital to understand ASW porosity over astronomically relevant conditions in order to effectively model its potential effects on these processes.

scholarly journals High-Precision Timing of Millisecond Pulsars and Precision Astrometry

1995 ◽  
Vol 166 ◽  
pp. 163-171 ◽  
Author(s):  
V. M. Kaspi
Keyword(s):  
Solar System ◽  
High Precision ◽  
Reference Frames ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
Solar System Objects ◽  
Optical Reference ◽  
Precision Astrometry

We present the technique of long-term, high-precision timing of millisecond pulsars as applied to precision astrometry. We provide a tutorial on pulsars and pulsar timing, as well as up-to-date results of long-term timing observations of two millisecond pulsars, PSRs B1855+09 and B1937+21. We consider the feasibility of tying the extragalactic and optical reference frames to that defined by solar system objects, and we conclude that precision astrometry from millisecond pulsar timing has a bright future.

scholarly journals Iron isotope evidence for very rapid accretion and differentiation of the proto-Earth

2020 ◽  
Vol 6 (7) ◽  
pp. eaay7604 ◽  
Author(s):  
Martin Schiller ◽  
Martin Bizzarro ◽  
Julien Siebert
Keyword(s):  
Solar System ◽  
Isotope Composition ◽  
Terrestrial Planets ◽  
Carbonaceous Chondrites ◽  
Iron Isotope ◽  
System Composition ◽  
Solar System Objects ◽  
History Of ◽  
Isotope Evidence ◽  
Enstatite Chondrites

Nucleosynthetic isotope variability among solar system objects provides insights into the accretion history of terrestrial planets. We report on the nucleosynthetic Fe isotope composition (μ54Fe) of various meteorites and show that the only material matching the terrestrial composition is CI (Ivuna-type) carbonaceous chondrites, which represent the bulk solar system composition. All other meteorites, including carbonaceous, ordinary, and enstatite chondrites, record excesses in μ54Fe. This observation is inconsistent with protracted growth of Earth by stochastic collisional accretion, which predicts a μ54Fe value reflecting a mixture of the various meteorite parent bodies. Instead, our results suggest a rapid accretion and differentiation of Earth during the ~5–million year disk lifetime, when the volatile-rich CI-like material is accreted to the proto-Sun via the inner disk.

scholarly journals Solar System Science with Robotic Telescopes

2011 ◽  
Vol 7 (S285) ◽  
pp. 352-354
Author(s):  
T. A. Lister
Keyword(s):  
Solar System ◽  
Automated System ◽  
System Science ◽  
Sky Surveys ◽  
The Earth ◽  
Solar System Objects ◽  
Robotic Telescopes ◽  
On Line ◽  
Near Earth Objects

AbstractAn increasing number of sky surveys is already on-line or soon will be, leading to a large boost in the detection of Solar System objects of all types. For Near-Earth Objects (NEOs) that could potentially hit the Earth, timely follow-up is essential. I describe the development of an automated system which responds to new detections of NEOs from Pan-STARRS and automatically observes them with the LCOGT telescopes. I present results from the first few months of operation, and plans for the future with the 6-site, 40-telescope global LCOGT Network.

Sign in / Sign up

Export Citation Format

Share Document