scholarly journals The physical and dynamical characteristics of the asteroid 4940 Polenov

2021 ◽  
pp. 39-49
Author(s):  
E. Vchkova-Bebekovska ◽  
N. Todorovic ◽  
A. Kostov ◽  
Z. Donchev ◽  
G. Borisov ◽  
...  
Keyword(s):  
Outer Part ◽  
Astronomical Observatory ◽  
Inversion Method ◽  
Main Belt ◽  
Dynamical Characteristics ◽  
Photometric Observations ◽  
Synodic Period ◽  
Solar System Object ◽  
Stability Time ◽  
Astronomical Station

The asteroid (1986 QY4) 4940 Polenov is the first Solar system object whose 3D shape is determined using the observations from the newly built Astronomical Station Vidojevica (ASV). Here we present the results of photometric observations for Polenov, gathered from the ASV, and from the Bulgarian National Astronomical Observatory (BNAO) Rozhen, during 2014, 2019 and 2020 apparitions. Polenov is a 17.8km object located in the outer part of the main belt and belongs to the asteroid family Themis. We have determined the lightcurves, the synodic period of 4.161?0.001 h, as well as the solution for the shape and spin axis. Using the lightcurve inversion method, the combination of our lightcurves and the sparse data from ATLAS{HKO and ATLAS-MLO, we also found the sidereal period, indicating a retrograde rotation of the asteroid, with two possible mirrored pole solutions. The ratio of the largest to smallest reecting surface is about 1.4. In addition, we studied the dynamical properties of the asteroid and obtained a long stability time that exceeds 0.4 Gyrs.

Shape and spin of asteroid 967 Helionape

2017 ◽  
Vol 12 (S330) ◽  
pp. 393-394
Author(s):  
G. Apostolovska ◽  
A. Kostov ◽  
Z. Donchev ◽  
E. Vchkova Bebekovska ◽  
O. Kuzmanovska
Keyword(s):  
Family Member ◽  
Planetary System ◽  
Sparse Data ◽  
Astronomical Observatory ◽  
Inversion Method ◽  
Shape Parameters ◽  
Spin Vector ◽  
Main Belt ◽  
Shape Model ◽  
Geometric Conditions

AbstractKnowledge of the spin and shape parameters of the asteroids is very important for understanding of the conditions during the creation of our planetary system and formation of asteroid populations. The main belt asteroid and Flora family member 967 Helionape was observed during five apparitions. The observations were made at the Bulgarian National Astronomical Observatory (BNAO) Rozhen, since March 2006 to March 2016. Lihtcurve inversion method (Kaasalainen et al. (2001)), applied on 12 relative lightcurves obtained at various geometric conditions of the asteroid, reveals the spin vector, the sense of rotation and the preliminary shape model of the asteroid. Our aim is to contribute in increasing the set of asteroids with known spin and shape parameters. This could be done with dense lightcurves, obtained during small number of apparitions, in combination with sparse data produced by photometric asteroid surveys such as the Gaia satellite (Hanush (2011)).

scholarly journals Photometry and shape modeling of Mars crosser asteroid (1011) Laodamia

2014 ◽  
pp. 79-85 ◽  
Author(s):  
G. Apostolovska ◽  
Z. Donchev ◽  
A. Kostov ◽  
V. Ivanova ◽  
G. Borisov ◽  
...  
Keyword(s):  
Sparse Data ◽  
Astronomical Observatory ◽  
Shape Modeling ◽  
Inversion Method ◽  
Shape Parameters ◽  
Spin Vector ◽  
Shape Model ◽  
Photometric Observations ◽  
Vector Sense

An analysis of photometric observations of Mars crosser asteroid 1011 Laodamia conducted at Bulgarian National Astronomical Observatory Rozhen over a twelve year interval (2002, 2003, 2004, 2006, 2007, 2008, 2011, 2012 and 2013) is made. Based on the obtained lightcurves the spin vector, sense of rotation, and preliminary shape model of (1011) Laodamia have been determined using the lightcurve inversion method. The aim of this investigation is to increase the set of asteroids with known spin and shape parameters and to contribute in improving the model in combination with other techniques and sparse data produced by photometric asteroid surveys such as Pan-STARRS or GAIA.

Asteroid collisions as origin of debris disks: Asteroid shape reconstruction from BNAO Rozhen photometry

2019 ◽  
Vol 15 (S350) ◽  
pp. 451-453
Author(s):  
G. Apostolovska ◽  
E. Vchkova Bebekovska ◽  
A. Kostov ◽  
Z. Donchev
Keyword(s):  
Laboratory Experiments ◽  
Extrasolar Planets ◽  
Shape Reconstruction ◽  
Inversion Method ◽  
Debris Disks ◽  
Shape Parameters ◽  
Zodiacal Cloud ◽  
Photometric Observations ◽  
Different Shapes ◽  
Asteroid Surface

AbstractAs a result of collisions during their lifetimes, asteroids have a large variety of different shapes. It is believed that high velocity collisions or rotational spin-up of asteroids continuously replenish the Sun’s zodiacal cloud and debris disks around extrasolar planets (Jewitt (2010)). Knowledge of the spin and shape parameters of the asteroids is very important for understanding collision asteroid processes. Lately photometric observations of asteroids showed that variations in brightness are not accompanied by variations in colour index which indicate that the shape of the lightcurve is caused by varying illuminations of the asteroid surface rather than albedo variations over the surface. This conclusion became possible when photometric investigations were combined with laboratory experiments (Dunlap (1971)). In this article using the convex lightcurve inversion method we obtained the sense of rotation, pole solutions and preliminary shape of 901 Brunsia.

Gaia spectroscopic view of the asteroid main belt and beyond

2021 ◽  
Author(s):  
Marco Delbo ◽  
Laurent Galluccio ◽  
Francesca De Angeli ◽  
Paolo Tanga ◽  
Alberto Cellino ◽  
...  
Keyword(s):  
Solar System ◽  
Preliminary Investigation ◽  
Planetary Science ◽  
Reflectance Spectra ◽  
Physical Parameters ◽  
The Novel ◽  
Main Belt ◽  
Compositional Gradient ◽  
Solar System Object ◽  
Science Community

<div class="">Asteroids reflectance spectra in the visible light will be one of the novel products of the Gaia Data Release 3 (DR3). These spectra are produced from Gaia observations obtained by means of the blue and red photometers — the so-called BP and RP, respectively. We will review the strategy adopted to produce asteroid reflectance spectra from BP-RP data, focusing on the choice of spectro-photometric calibrations computed taking into account solar system object astrometry and suitable lists of solar-analog stars.</div> <div class=""> </div> <div class="">Our preliminary investigation shows that we will be able to obtain reflectance spectra for asteroids as small as some km in the main belt, by exploiting the fact that each object has been observed multiple times by Gaia. We will show the capability of Gaia to probe the detailed compositional gradient of the main belt down to small sizes and to study correlations between spectral classes and other asteroid physical parameters, such as albedo and size.</div> <div class=""> </div> <div class="">Concerning the brightest asteroids, we expect to have substantial signal at wavelengths shorter than 450 nm, allowing Gaia to examine this region of the spectrum that has been poorly investigated by ground-based asteroid spectroscopic surveys. This region is characterised by the presence of a reflectance downturn that is diagnostic for the composition of classes of primitive asteroids, for instance those including the parent bodies of carbonaceous chondrites. These asteroids may have played an important role for the delivery of prebiotic compounds to Earth during the early phases of solar system' s history and, as such, are at the center of attention of the planetary science community. </div>

scholarly journals Observations of comets and minor planets at Kiev comets station (585)

2009 ◽  
Vol 5 (S263) ◽  
pp. 298-302
Author(s):  
Alexander R. Baransky ◽  
Klim I. Churuymov ◽  
Vasyl A. Ponomarenko
Keyword(s):  
Astronomical Observatory ◽  
Minor Planets ◽  
Photometric Observations ◽  
National University

AbstractWe present the results of astrometric and photometric observations of comets and minor planets obtained at the Kiev comet station (Code MPC 585) of the Astronomical Observatory of Kyiv Shevchenko National University in 2006-2009. The 2318 position observations of 176 comets, 302 observations of 57 numbered minor planets, and 220 observations of 30 unnumbered minor planets were obtained. The accuracy of the astrometric observations of the comets is analyzed.

A modified form of diffraction tomography to image boundary structures

Geophysics ◽  
1993 ◽  
Vol 58 (8) ◽  
pp. 1136-1147
Author(s):  
Thorbjørn Rekdal ◽  
Durk J. Doornbos
Keyword(s):  
Seismic Tomography ◽  
Outer Part ◽  
Inversion Method ◽  
Unknown Boundary ◽  
Diffraction Tomography ◽  
Common Procedure ◽  
Sea Bottom ◽  
Receiver Array ◽  
Wavefield Extrapolation ◽  
Rough Sea

Wavefield extrapolation downward from the surface, as applied in migration and associated inversion methods, is a common procedure to image subsurface reflectors. These methods require adequate (i.e., extensive and unaliased) sampling of the surface wavefield. Seismic tomography on the other hand, relates parameters of the upward propagated wavefield to the diffracting image, and sampling requirements are less severe; it is usually the only option to image deep structures from sparse data. The ordinary form of ray tomography, however, imposes a severe smoothness constraint on the boundary; in particular the “tops” and “valleys” of a relatively rough structure are not well‐resolved. We have implemented a generalized form of tomography, which uses both the ray term and the diffraction term linearized in the boundary perturbation. We introduce a generalized reflection coefficient that can be linearized in terms of the (unknown) boundary gradient, and we demonstrate the adequacy of this approximation with the help of synthetic seismograms. We compare the performance of the new inversion method with migration and ray tomography in a number of model experiments where a source and receiver array are used to image (1) a rough sea bottom and (2) a rough sedimentary layer boundary. In these experiments the new method is superior, especially in the outer part of the inversion region where migration and seismic tomography suffer seriously because of the lack of adequate surface information. Even for well‐controlled surveys there is the potential to successfully image a much larger area of the reflector than is possible with migration. Our experiments involved a single reflector in a known velocity‐density structure. The method’s applicability or modifications required when relaxing these assumptions, remains to be investigated.

Modeling asteroid shapes using BNAO Rozhen photometric data in combination with sparse data

2021 ◽  
Author(s):  
Gordana Apostolovska ◽  
Elena Vchkova Bebekovska ◽  
Galin Borisov ◽  
Andon Kostov ◽  
Zahary Donchev
Keyword(s):  
Weather Conditions ◽  
Sparse Data ◽  
Space Mission ◽  
Physical Characteristics ◽  
Photometric Data ◽  
Inversion Method ◽  
Physical Parameters ◽  
Minor Planets ◽  
Photometric Observations ◽  
Dense Data

<p>Our work aims to demonstrate how the use of our dense lightcurves in combination with sparse data from diverse sources will affect the results for obtaining the sidereal period, shape models, and ecliptic pole solution for a chosen asteroid.</p> <p>Photometric observations of minor planets are traditional at the Bulgarian National Astronomical observatory (BNAO) Rozhen. They started with photoelectric observations in 1991, and later have been continued as CCD photometric observations on all three telescopes: 2m Ritchey-Chretién-Coudé, 50cm/70cm, and 60cm Cassegrain. We hope that the new 1.5 m robotic telescope planned to be operational next year will be also partly devoted to the study of minor planets.</p> <p>Our target, 339 Dorothea, is a main-belt asteroid, a large member of the Eos dynamical family. For the last 8 years, between 2013 and 2021, the asteroid 339 Dorothea was observed at BNAO Rozhen during six apparitions and several dense lightcurve were obtained. We used these dense photometric data in lightcurve inversion method and reconstruct the model of the asteroid, determining its sidereal period, shape, and pole orientation. Afterward, using sparse data from the AstDys database with an accuracy of 0.01 mag in combination with the obtained dense data, new trials for calculating and improving the physical characteristics of the asteroid 339 Dorothea were made.</p> <p>Unlike very low photometric accuracy in ground-based sparse photometry, space missions have provided astronomers with sparse photometry with extremely high accuracy, for example, the ESA GAIA mission. The NEOWISE mission has observations only for a limited number of asteroids. Fortunately, we were able to find some sparse data for our target and use this accurate photometry in combination with our dense lightcurves for the reconstruction of the asteroid spin state and shape model.</p> <p>Due to bad weather conditions and limited allocation of observing time at the BNAO Rozhen dedicated to our project, we have at our disposal full and partial dense lightcurves obtained for several more asteroids in few different apparitions. Combining these dense data with ground-based or space mission sparse data will contribute to enlarging the database of asteroids with known physical characteristics. Enriching the number of asteroids with known physical parameters would provide more data for future statistical analysis and could help in answering the questions for the evolution of our Solar System. </p>

scholarly journals Global Astrophysical Telescope System — telescope No. 2

2013 ◽  
Vol 9 (S301) ◽  
pp. 437-438
Author(s):  
Krzysztof Kamiński ◽  
Roman Baranowski ◽  
Monika Fagas ◽  
Wojciech Borczyk ◽  
Wojciech Dimitrov ◽  
...  
Keyword(s):  
Variable Stars ◽  
Astronomical Observatory ◽  
Spectroscopic Observations ◽  
Photometric Observations ◽  
Nearly Continuous ◽  
Telescope System

AbstractWe present the new, second spectroscopic telescope of Poznań Astronomical Observatory. The telescope allows automatic simultaneous spectroscopic and photometric observations and is scheduled to begin operation from Arizona in autumn 2013. Together with the telescope located in Borowiec, Poland, it will constitute a perfect instrument for nearly continuous spectroscopic observations of variable stars. With both instruments operational, the Global Astrophysical Telescope System will be established.

scholarly journals NEW CCD TIMES OF MINIMA OF ECCENTRIC ECLIPSING BINARY SYSTEMS IN 2017-2019

2020 ◽  
pp. 1-16
Author(s):  
M.-J. Jeong ◽  
C.-H. Kim ◽  
M.-H. Song ◽  
E.-C. Sung ◽  
J.-H. Park ◽  
...  
Keyword(s):  
Binary Systems ◽  
Astronomical Observatory ◽  
Republic Of Korea ◽  
Eclipsing Binary ◽  
Photometric Observations

We present 88 times of minima for 56 eccentric eclipsing binary systems determined from photometric observations at the Sobaeksan Optical Astronomical Observatory (SOAO) in Republic of Korea from February 2017 to December 2019.

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