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>

Photometric observations of the main-belt asteroid 665 Sabine and Minor Planet Bulletin

2021 ◽  
Author(s):  
Nick Sioulas
Keyword(s):  
Solar System ◽  
Rotation Period ◽  
Space Mission ◽  
Minor Planet ◽  
Minor Planets ◽  
Official Publication ◽  
Main Belt ◽  
Dwarf Planets ◽  
Photometric Observations ◽  
The Town

<p><strong>Photometric observations of the main-belt asteroid 665 Sabine and Minor Planet Bulletin</strong></p> <p> </p> <p>Nick Sioulas</p> <p>NOAK Observatory, Stavraki (IAU code L02) Ioannina, Greece ([email protected])</p> <p><strong>Introduction</strong></p> <p>In this work, the photometric observations of the main-belt asteroid 665 Sabine were conducted from the NOAK Observatory, in Greece in order to determine its synodic rotation period. The results were submitted to Asteroid Lightcurve Photometry Database (ALCDEF) and Minor Planet Bulletin.</p> <p><strong>Abstract</strong></p> <p>The Minor Planet Bulletin is the official publication of the Minor Planets Section of the Association of Lunar and Planetary Observers (ALPO). All amateurs and professionals can publish their asteroid photometry results, including lightcurves, H-G parameters, color indexes, and shape/spin axis models. It is also the refereed journal by the SAO/NASA ADS. All MPB papers are indexed in the ADS.</p> <p> </p> <p>The lightcurve of an asteroid can be used to determine the period, the shape and its size. We can also understand its composition (if it is a solid body or something else) and the orientation of the spin axes. Due to the high number of the asteroids the need of measuring them is important and all available telescopes are necessary to track them.</p> <p> </p> <p>My amateur observatory participates in the effort to record all these objects in the Solar System. It also conducts observations of various objects and other phenomena such as exoplanet transits, contributing to the Ariel Space Mission with the Exoclock Project, asteroid occultations and comet photometry.</p> <p>The observatory is registered in IAU as L02, «NOAK Observatory, Stavraki», in the town of Ioannina, Greece.</p> <p> </p> <p><strong>References</strong></p> <p>[1] Roger Dymock: Asteroids and Dwarf Planets</p> <p>[2] Brian D. Warner: A Practical Guide to Lightcurve Photometry and Analysis</p> <p>[3] http://alcdef.org/index.php</p> <p>[4] http://www.minorplanet.info/MPB/</p>

scholarly journals The analysis of SuperWASP photometric data for the overcontact binary QW Gem

2013 ◽  
pp. 47-51 ◽  
Author(s):  
A. Cséki
Keyword(s):  
Radial Velocity ◽  
Surface Brightness ◽  
Photometric Data ◽  
Physical Parameters ◽  
Eclipsing Binary ◽  
Photometric Observations ◽  
Modeling Code

The paper presents an analysis of photometric observations of the eclipsing binary QW Gem. The orbital and physical parameters of the system are derived using the modeling code by G. Djurasevic. Photometric observations are obtained from the SuperWASP public archive and the spectroscopic elements are adopted from a recently published radial velocity study. The results suggest that QW Gem is a binary in overcontact configuration, consisting of two stars of similar surface brightness but in different evolutionary stages.

scholarly journals Energy Distribution, Photometry and Physical Characteristics of the Sun and Solar Analogs

1986 ◽  
Vol 7 ◽  
pp. 853-861
Author(s):  
I. N. Glushneva ◽  
E. A. Markova ◽  
A. V. Kharitonov
Keyword(s):  
Solar Energy ◽  
Energy Distribution ◽  
Physical Characteristics ◽  
Photometric Data ◽  
Physical Parameters ◽  
Photometric System ◽  
The Sun ◽  
Color Indices ◽  
Effective Temperatures ◽  
Solar Analogs

AbstractColor indices of solar analogs in the Vilnius seven-color photometric system are discussed. The physical parameters (effective temperatures, radii and luminosities) for solar analogs with reliable spectrophotometric and photometric data were obtained by means of infrared fluxes. The effective temperatures of 16 Cyg A and B, which are considered to be the closest solar analogs are 5854 and 5664 K, respectively. The radii of both stars are in the range of 1 Ro < R < 1.4 Ro and luminosities 1.2Lo < L < 2.1 Lo for 16 Cyg A and Lo < L < 1.7 Lo for 16 Cyg B depending on different evaluations of the distances. We find that the relative solar energy distribution in the 0.33 – 1.25 μm range determined by Neckel and Labs (1984) is reliable enough, however the absolute fluxes are slightly too low at the maximum of energy distribution.

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.

scholarly journals Studies for slowly rotating asteroids (168) Sibylla and (346) Hermentaria

2015 ◽  
Vol 10 (S318) ◽  
pp. 185-192
Author(s):  
Xiaobin Wang ◽  
Karri Muinonen ◽  
Xianming L. Han ◽  
Chi-Tai Kwok
Keyword(s):  
Monte Carlo ◽  
Oblate Spheroid ◽  
Prolate Spheroid ◽  
Photometric Data ◽  
Inversion Method ◽  
Physical Parameters ◽  
Interior Structure ◽  
Physical Processes ◽  
Spin Period ◽  
First Time

AbstractStudies for spin parameters and shapes of asteroids provide us with important information about the interior structure of asteroids and the physical processes they have undergone. A large sample of basic physical parameters can help us also understand the evolution of asteroids. There is scarce information for slowly-rotating larger asteroids because more effort is required for observing them. Because of this, we have established an international collaboration to study slowly-rotating asteroids. As the first step of this project, we have observed asteroids (168) Sibylla and (346) Hermentaria in 2014 and 2015 using several telescopes located in China, Chile, and U.S.A. Combining previous photometric data with our new data, we have performed preliminary analyses and obtained spin parameters and shapes with their uncertainties for these two slowly-rotating asteroids for the first time, using the convex inversion method and the virtual photometry Monte Carlo method. A pair of pole solutions for (168) Sibylla are found around (4.3°, 53.5°) and (183.5°, 52.6°) with a period of 47.0000 h. We have found that the shape of Sibylla resembles an oblate spheroid. For (346) Hermentaria, we have also found a pair of pole solutions around (134.5°, 16.7°) and (321.5°, 14.5°) with comparable rms-values with a spin period of about 17.79000 h, and a shape resembling a prolate spheroid.

Polarimetric and photometric observations of CB54, with analysis of four other dark clouds

2021 ◽  
Vol 503 (4) ◽  
pp. 5274-5290
Author(s):  
A K Sen ◽  
V B Il’in ◽  
M S Prokopjeva ◽  
R Gupta
Keyword(s):  
Magnetic Field ◽  
Near Infrared ◽  
Galactic Plane ◽  
Photometric Data ◽  
Dust Particles ◽  
Dark Cloud ◽  
Dark Clouds ◽  
High Polarization ◽  
Field Parallel ◽  
Photometric Observations

ABSTRACT We present the results of our BVR-band photometric and R-band polarimetric observations of ∼40 stars in the periphery of the dark cloud CB54. From different photometric data, we estimate E(B − V) and E(J − H). After involving data from other sources, we discuss the extinction variations towards CB54. We reveal two main dust layers: a foreground, E(B − V) ≈ 0.1 mag, at ∼200 pc and an extended layer, $E(B-V) \gtrsim 0.3$ mag, at ∼1.5 kpc. CB54 belongs to the latter. Based on these results, we consider the reason for the random polarization map that we have observed for CB54. We find that the foreground is characterized by low polarization ($P \lesssim 0.5$ per cent) and a magnetic field parallel to the Galactic plane. The extended layer shows high polarization (P up to 5–7 per cent). We suggest that the field in this layer is nearly perpendicular to the Galactic plane and both layers are essentially inhomogeneous. This allows us to explain the randomness of polarization vectors around CB54 generally. The data – primarily observed by us in this work for CB54, by A. K. Sen and colleagues in previous works for three dark clouds CB3, CB25 and CB39, and by other authors for a region including the B1 cloud – are analysed to explore any correlation between polarization, the near-infrared, E(J − H), and optical, E(B − V), excesses, and the distance to the background stars. If polarization and extinction are caused by the same set of dust particles, we should expect good correlations. However, we find that, for all the clouds, the correlations are not strong.

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.

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.

Ultrasonic device for real-time sewage velocity and suspended particles concentration measurements

2009 ◽  
Vol 60 (1) ◽  
pp. 117-125 ◽  
Author(s):  
F. Abda ◽  
A. Azbaid ◽  
D. Ensminger ◽  
S. Fischer ◽  
P. François ◽  
...  
Keyword(s):  
Data Analysis ◽  
Suspended Solids ◽  
Weather Conditions ◽  
Suspended Particles ◽  
Inversion Method ◽  
Ultrasonic Device ◽  
Size Classes ◽  
Identification Method ◽  
Spectral Identification ◽  
Water Height

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller standard deviation values for the Doppler frequency extracted by the Spectral Identification method. A specific algorithm was also developed for the water height measurements. It relies on the water surface acoustic impedance rupture and its peak localisation and behaviour in the collected backscattering data. This algorithm was positively tested on long time measurements on the same wastewater collector. A large part of the article is devoted to the measurements of the suspended solids concentrations. Our data analysis consists in the adaptation of the well described acoustic behaviour of sand to the behaviour of wastewater particles. Both acoustic attenuation and acoustic backscattering data over multiple frequencies are analyzed for the extrapolation of size classes and respective concentrations. Under dry weather conditions, the massic backscattering coefficient and the overall size distribution showed similar evolution whatever the measurement site was and were suggesting a global wastewater particles behaviour. By comparison to sampling data, our data analysis lead to the characterization of two particle groups: the ones occurring during rain events and the ones typical of wastewater under dry weather conditions. Even with already encouraging results on the several weeks of data recorded on several wastewater collectors, the validation of our data inversion method is still under progress.

scholarly journals Potential possibilities of water retention in agricultural loess catchments

2016 ◽  
Vol 30 (1) ◽  
pp. 141-149 ◽  
Author(s):  
Tomasz Zubala ◽  
Magdalena Patro
Keyword(s):  
Spatial Planning ◽  
Water Retention ◽  
Soil Cover ◽  
Weather Conditions ◽  
Physical Parameters ◽  
Sample Analysis ◽  
Protective Measures ◽  
Economic Problems ◽  
Small Catchments

Abstract The growing water deficit and the increased demand for water, as well as economic problems and inadequate spatial planning in many regions indicate a necessity of developing more effective rules of programming and realisation of works concerning the water management in small catchments. The paper presents a sample analysis of the possibilities of increasing water retention in the agricultural loess catchments with periodic streams. The scope of the study included the determination of physical parameters of selected sub-catchments (geometry, soil cover, land use, etc.) and of the sources of threat to water resources, resulting from construction and geomorphological conditions. Pre-design assumptions of dammings were developed, taking into account anti-erosion protective measures, and treatments increasing the landscape retention of water were proposed. Creating surface retention objects should be an important source of water in simplified agroecosystems, especially in regions, where productivity to a great extent depends on natural weather conditions. Proper management of the fourth-order loess basin of the Ciemięga River (area of about 150 km2, the presence of 50 lateral valleys) could give a temporary reservoir retention reaching 500 thousand m3. Farmers should be encouraged to seek “own water sources” (including the accumulation of water within wasteland), using appropriate economic instruments (tax reliefs for the documented volume of retained water, e.g. in small retention reservoirs).

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