Shape models and dynamical properties of basaltic asteroids outside the dynamical Vesta family

Through numerical modeling, Nesvorny et al. (2008) showed that asteroids can migrate due to Yarkovsky drift and resonances to outside of the boundaries of the Vesta family. In particular, they found that objects which end up in the scattered resonances region (so-called Cell I, defined by orbital elements 2.2 AU < a < 2.3 AU, 0.05 < e < 0.2, 0 < i deg < 10 deg) typically have retrograde rotations and thermal parameters that maximize Yarkovsky drift rates. These autors also showed, that asteroids migrating to the low inclination region (Cell II defined by 2.32 AU < a < 2.48 AU, 0.05 < e < 0.2, 2 deg We performe photometric observations and determine spins and shapes of V-type objects in Cell I and Cell II in order to characterize the dynamical properties of these asteroids more accurately. The results of dynamical modelling show that some asteroids may have migrated to their current location from the Vesta family within ~2 Gy. There are objects, however, whose origin in another parent body may also be plausible. This may support the hypothesis that the number of differentiated basaltic objects in the inner and middle Main Belt should be much higher than previously assumed. We will present preliminary results for the first ~10 asteroids in Cell I and Cell II.

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Verification of the V-type asteroids rotation distribution outside Vesta family

10.5194/epsc2020-1128 ◽

2020 ◽

Author(s):

Volodymyr Troianskyi ◽

Keyword(s):

Numerical Modelling ◽

Thermal Parameters ◽

Orbital Elements ◽

Main Belt ◽

Preliminary Results ◽

Yarkovsky Effect ◽

Photometric Observations

The main objective of the study is the verification of the V-type rotation distribution. Though numerical modelling, Nesvorny et al. (2008) showed that asteroids can migrate through Yarkovsky effect and resonaces outside the boundaries of the Vesta family. In particular they found that objects which end up in the scattered resonances region (so-called Cell I, defined by orbital elements 2.2 AU < a < 2.3 AU, 0.05 < e < 0.2, 0 the Yarkovsky drift. Consequently, most of the V-types in Cell I should be retrograde rotating. Similarly showed that asteroids migrating to the low inclination region (Cell II defined by 2.32 AU < a < 2.48 AU, 0.05 < e < 0.2, 2 deg We perform photometric observations and determine spins and shapes of V-type objects in Cell I and II to verify the predicted statistics of sense of rotation. Finding significantly un-matching statistics for rotational properties may strengthen the idea that there may be fragments of other (than Vesta) differentiated planetesimals in the inner main belt. We show preliminary results for the first few asteroids in Cell I and II.

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Observational Data and Orbits of the Asteroids Discovered at the Molėtai Observatory in 2008–2009

Open Astronomy ◽

10.1515/astro-2017-0265 ◽

2016 ◽

Vol 25 (4) ◽

Author(s):

K. Černis ◽

I. Wlodarczyk ◽

J. Zdanavičius

Keyword(s):

Observational Data ◽

Minor Planet ◽

Orbital Elements ◽

Main Belt ◽

Ccd Observations ◽

Near Earth Objects ◽

Asteroids And Comets

AbstractWe present the statistics of the asteroids observed and discovered at the Molėtai Observatory, Lithuania, in 2008–2009 within the project for astrometric observations of the near-Earth objects (NEOs), the main belt asteroids and comets. CCD observations of the asteroids were obtained with the 35/51-cm Maksutov-type meniscus telescope. In the Minor Planet Circulars and the Minor Planet Electronic Circulars (2008–2009), 11 900 astrometric positions of 2522 asteroids were published. Among them 95 were new asteroids, including four belonging to the Trojan group: (352655) 2008QX28, 2008 SE8, (353194) 2009 SM100 and (264068) 2009 SQ148. For the asteroids discovered at Molėtai their precise orbits are calculated. Because of short observational arc, a few asteroids have low-precision orbits and some asteroids are considered lost. For the three Main Belt asteroids with low-precision orbital elements, 2008 QP32, 2008 SD8 and 2008 SG150, we present their ephemerides for 2017. They can be brighter than 20 mag.

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Photometric Observations of Three Double Stars by the Occultation Method — Comparison with Interferometric Results and with Preliminary Results of HIPPARCOS

International Astronomical Union Colloquium ◽

10.1017/s0252921100007107 ◽

1992 ◽

Vol 135 ◽

pp. 546-548

Author(s):

M. Froeschlé ◽

C. Meyer

Keyword(s):

Diffraction Pattern ◽

Method Comparison ◽

Short Description ◽

Double Star ◽

Preliminary Results ◽

Double Stars ◽

Photometric Observations

AbstractWe first briefly recall the geometry of the occultation of a double star by the Moon’s edge. Then we give a short description of the principle of the formation of the diffraction pattern. We present the results for three double stars and compare them with those obtained by other methods.

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Observational Data and Orbits of the Asteroids Discovered at the Baldone Observatory in 2008–2013

Open Astronomy ◽

10.1515/astro-2017-0226 ◽

2015 ◽

Vol 24 (3) ◽

Cited By ~ 1

Author(s):

K. Černis ◽

I. Wlodarczyk ◽

I. Eglitis

Keyword(s):

Observational Data ◽

Ccd Camera ◽

Minor Planet ◽

Orbital Elements ◽

Main Belt ◽

Schmidt Telescope ◽

Ccd Observations ◽

Near Earth Objects ◽

Asteroids And Comets

AbstractThe paper presents statistics of the asteroids observed and discovered at the Baldone Observatory, Latvia, in 2008–2013 within the project for astrometric observations of the near-Earth objects (NEOs), the main belt asteroids and comets. CCD observations of the asteroids were obtained with the 0.80/1.20 m, f/3 Schmidt telescope and a ST-10XME 15 × 10 mm CCD camera. In the Minor Planet Circulars and the Minor Planet Electronic Circulars (2008–2013) we published 3511 astrometric positions of 826 asteroids. Among them, 43 asteroids were newly discovered at Baldone. For 36 of these asteroids the precise orbits are calculated. Because of short observational arc and small number of observations, a few asteroids have low-precision orbits and their tracks have been lost. For seven objects with poorly known orbits we present their ephemerides for 2015–2016. The orbits and the evolution of orbital elements of two asteroids, (428694) 2008 OS9 from the Apollo group and the Centaur (330836) Orius (2009 HW77), are recalculated including new observations obtained after 2011.

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Observation of 44(Nysa) Asteroid by IST60 Telescope

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319003387 ◽

2018 ◽

Vol 14 (A30) ◽

pp. 40-40

Author(s):

Remziye Canbay ◽

Fulin Gursoy

Keyword(s):

Minor Planet ◽

Web Interface ◽

Orbital Elements ◽

Main Belt

AbstractIn this study, the main belt asteroid (44) Nysa, which is also a known member of the Nysian asteroid family, was observed by IST60 telescope. The orbital elements were compared with MPO(Minor Planet Center) and NASA Horizons Web-Interface results.

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Physical parameters of selected Gaia mass asteroids

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936380 ◽

2020 ◽

Vol 638 ◽

pp. A11

Author(s):

E. Podlewska-Gaca ◽

A. Marciniak ◽

V. Alí-Lagoa ◽

P. Bartczak ◽

T. G. Müller ◽

...

Keyword(s):

Thermal Inertia ◽

Physical Property ◽

Physical Parameters ◽

Good Precision ◽

Main Belt ◽

Shape Models ◽

Solar System Bodies ◽

Fundamental Physical Property ◽

Thermophysical Modeling ◽

The Masses

Context. Thanks to the Gaia mission, it will be possible to determine the masses of approximately hundreds of large main belt asteroids with very good precision. We currently have diameter estimates for all of them that can be used to compute their volume and hence their density. However, some of those diameters are still based on simple thermal models, which can occasionally lead to volume uncertainties as high as 20–30%. Aims. The aim of this paper is to determine the 3D shape models and compute the volumes for 13 main belt asteroids that were selected from those targets for which Gaia will provide the mass with an accuracy of better than 10%. Methods. We used the genetic Shaping Asteroids with Genetic Evolution (SAGE) algorithm to fit disk-integrated, dense photometric lightcurves and obtain detailed asteroid shape models. These models were scaled by fitting them to available stellar occultation and/or thermal infrared observations. Results. We determine the spin and shape models for 13 main belt asteroids using the SAGE algorithm. Occultation fitting enables us to confirm main shape features and the spin state, while thermophysical modeling leads to more precise diameters as well as estimates of thermal inertia values. Conclusions. We calculated the volume of our sample of main-belt asteroids for which the Gaia satellite will provide precise mass determinations. From our volumes, it will then be possible to more accurately compute the bulk density, which is a fundamental physical property needed to understand the formation and evolution processes of small Solar System bodies.

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Thermal properties of large main-belt asteroids observed by Herschel PACS

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037718 ◽

2020 ◽

Vol 638 ◽

pp. A84

Author(s):

V. Alí-Lagoa ◽

T. G. Müller ◽

C. Kiss ◽

R. Szakáts ◽

G. Marton ◽

...

Keyword(s):

Adaptive Optics ◽

Thermal Inertia ◽

Physical Models ◽

Absolute Calibration ◽

Calibration Error ◽

Main Belt ◽

Infrared Observations ◽

Fine Grained ◽

Shape Models ◽

First Time

Non-resolved thermal infrared observations enable studies of thermal and physical properties of asteroids via thermo-physical models provided the shape and rotational properties of the target are well determined. We used calibration-programme Herschel PACS data (70, 100, 160 μm) and state-of-the-art shape models derived from adaptive-optics observations and/or optical light curves to constrain for the first time the thermal inertia of twelve large main-belt asteroids. We also modelled previously well-characterised targets such as (1) Ceres or (4) Vesta as they constitute important benchmarks. Using the scale as a free parameter, most targets required a re-scaling ~5% consistent with what would be expected given the absolute calibration error bars. This constitutes a good cross-validation of the scaled shape models, although some targets required larger re-scaling to reproduce the IR data. We obtained low thermal inertias typical of large main belt asteroids studied before, which continues to give support to the notion that these surfaces are covered by fine-grained insulating regolith. Although the wavelengths at which PACS observed are longwards of the emission peak for main-belt asteroids, they proved to be extremely valuable to constrain size and thermal inertia and not too sensitive to surface roughness. Finally, we also propose a graphical approach to help examine how different values of the exponent used for scaling the thermal inertia as a function of heliocentric distance (i.e. temperature) affect our interpretation of the results.

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