FIRST RESULTS OF PROCESSING DIGITIZED V-PLATES TAKEN WITH THE TAUTENBURG 2m SCHMIDT TELESCOPE

The process of treatment of about 500 digitized plates has started in MAO NAS of Ukraine. Plates were taken with the Tautenburg 2m Schmidt telescope in 1963-1989. Linear dimensions of plates are 24x24 cm with a working field of 3.3x3.3 degrees and a scale of 51.4 "/ mm. Astronegatives were digitized on the Tautenburg Plate Scanner in five strips with linear dimensions of 5 400x23 800 px. The software developed in MAO NAS of Ukraine for the image processing of these scans takes into account the horizontal overlap and the vertical offset of strips. The photometric range of fixed objects is 12 magnitudes, around V = 7 m - 19 m , due to the separation of objects into faint and bright parts by their images’ diameters. Positions of stars and other fixed objects are obtained in the GAIA DR2 reference system. Magnitudes are defined in the V-band of the Johnson color system. The resulted positional accuracy defined from 180 plates’ processing is σ RA,DEC = 0.10"for both coordinates, photometric error on the whole range of magnitudes is σ V = 0.14 m . The convergence of resulted magnitudes with ones from photoelectric standards’ data is 0.19 m . In parallel with image processing and plate data reduction, the search for minor planets’ images was carried out. Nine positions and magnitudes of 4 asteroids registered on the plates obtained in 1963-1965 were defined and used for further analysis.

Near-UV Reddening Observed in the Reflectance Spectrum of High-inclination Centaur 2012 DR30

Centaurs with high orbital inclinations and perihelia (i > 60°; q ≳ 5 au) are a small group of poorly understood minor planets that are predicted to enter the giant planet region of the solar system from the inner Oort Cloud. As such, they are one of the few samples of relatively unaltered Oort Cloud material that can currently be directly observed. Here we present two new reflectance spectra of one of the largest of these objects, 2012 DR30, in order to constrain its color and surface composition. Contrary to reports that 2012 DR30 has variable optical color, we find that consistent measurements of its spectral gradient from most new and published data sets at 0.55–0.8 μm agree with a spectral gradient of S ′ ≃ 10 % ± 1 % / 0.1 μ m within their uncertainties. The spectral variability of 2012 DR30 at near-UV/blue and near-IR wavelengths, however, is still relatively unconstrained; self-consistent rotationally resolved follow-up observations are needed to characterize any spectral variation in those regions. We tentatively confirm previous detections of water ice on the surface of 2012 DR30, and we also consistently observe a steady steepening of the gradient of its spectrum from λ ∼ 0.6 μm toward near-UV wavelengths. Plausible surface materials responsible for the observed reddening may include ferric oxides contained within phyllosilicates and aromatic refractory organics.

Who Owns Space?

Space mining is no longer a figment of fringe science fiction. Due to the recent passage of the Space Resource Exploration and Utilization Act of 2015 (SREU Act), U.S. domestic space companies now have a semblance of legislative backing to launch commercial resource acquisition ventures in space. Previously, such companies floundered as capital from investors was reasonably sparse. Uncertainty created by the previously untested Outer Space Treaty (OST) perpetuated worry surrounding the existence of private property rights in space. With the passage of the recent SREU Act, many domestic worries were dismissed by the definitive granting of commercial property rights to U.S. citizens, yet equally many worries continue to surround the legitimacy of the SREU Act itself, as certain legal experts both inside and outside the U.S. argue the Act to be a violation of U.S. international obligations. In contrast to the OST, the SREU Act explicitly grants Americans the right to hold and obtain material resources from celestial bodies such as asteroids and minor planets. This paper examines the implications of such a legal gray area by examining the extent to which select clauses of the OST may or may not conflict with such definitive legislation. Ultimately, it is concluded that the issue is far from settled, as the existence of celestial property rights may not presently be as clear as investors might hope.

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

<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>

Axisymmetric landslides on top-shaped asteroids

Spin rates of minor planets or asteroids are known to have been affected by several agents including but not limited to tidal fly-bys, impacts and solar radiation. Surface processes like landslides occur as a result of such rotational changes. We study the evolution of landslides on top-shaped rubble pile asteroids like 101955 Bennu and 162173 Ryugu, with the underlying core modeled as two solid cones fused back to back. Using a depth averaged avalanche theory applicable to granular flows we solve for axisymmetric landslides occurring at various spin rates and regolith friction. Static regions on the surface corresponding to different spin rates are identified from an equilibrium analysis. We then solve for landslides initiated at different latitudes. It is found that landslides equilibrate at lower latitudes as the spin rate is increased. Beyond a critical spin rate regolith is shed from the equator. This critical spin is higher for a lower value of the semi-apex angle of the cone.

Prevention of NEO hazard: the Russian approach

Russian Academy of Sciences (RAS) is actively working to solve the problem of preventing Near-Earth Object (NEO) hazard. The article provides the goals and objectives of preventing NEO hazard, as well as ways to achieve them. The described ways of achieving the goal are applied in RAS best. The current state and prospects of the Russian contribution to the prevention of NEO hazard are considered. Statistical data on the dynamics of observation of minor planets by Russian telescopes is presented. The structure of the NEO part of hazardous situations classifier developed by Keldysh Institute of Applied Mathematics (KIAM RAS) and structure of perspective National System Security of space activities in outer space are presented, including the system’s response to event classified as dangerous. The article is accompanied by illustrations of potentially hazardous objects in the sky, made by telescopes of the International Network of Optical Telescopes (ISON), coordinated by the KIAM RAS.

Spectroscopic investigation of the large Potentially Hazardous Asteroid (52768) 1998OR2 within NEOROCKS EU project

<p>With an estimated diameter of about 2200m (http://neo.ssa.esa.int/), and a MOID (minimum orbital intersection distance) of 0.0154 au (6 Lunar Distances LD), (52768) 1998 OR2 is one of the largest known Potentially Hazardous Asteroid. On 29 April 2020 at 09:56 UTC 1998 OR2 had a very close passage to Earth at a distance of 0.042 au (16 LD). Close approaches by large asteroids like 1998 OR2 are a quite rare event.</p> <p>This asteroid has a highly eccentric orbit (e=0.57) with minor perturbations: this causes it to swap continuously. Moreover it is classified as Amor or Apollo asteroid  depending on the orbital phase.</p> <p>Within the NEOROCKS EU project (“The NEO Rapid Observation, Characterization and Key Simulations” - SU-SPACE-23-SEC-2019 from the Horizon 2020) - WP3-Task3.2 (Reflectance Spectroscopy) we observed 1998OR2 through the 120 cm “Galileo” telescope in Asiago using Boller & Chivens spectrograph instrument on 15 April 2020 when it was at 1.01 au heliocentric distance and 0.078 au distance from Earth.</p> <p> 1998 OR2, discovered on 24 July 1998 by NEAT program, is a fast rotator in the NEO population with a rotational period of 4.11 h  (Koehn et al, 2014; Skiff et al., 2019, and Warner and Stephens, 2020) and shows a large crater-like concavity through radar images (Virkki, A. K. 2020).</p> <p>Due to its rapid rotation, we were able to monitor the reflectance spectroscopy of 1998 OR2 for one nearly complete rotation during the night of 15 April 2020. We acquired 11 spectra, one every 20 minutes, spanning from 19:22 to 23.26 UTC. This allowed to investigate the possible variegation of the object across its surface and potentially connected with its big crater.</p> <p>It is unlikely that one of these large asteroids  could  impact the Earth over the next century, in fact also this asteroid poses no possibility of impact for at least the next 200 years, even if in its next close approach to Earth in 2079,  it will pass by close ,  about four times the lunar distance. It is however extremely important to keep these objects monitored and to investigate their physical and compositional properties to implement mitigation techniques.</p> <p>In this work we will present optical spectroscopic characterization of 1998 OR2 and the comparison of the taxonomic classification resulting from these spectra with the Xk obtained by Binzel et al. (2019). Additionally we will investigate its possible surface variegation according to the geometry of observation and the asteroid shape.</p> <p>Acknowledgement: This work has been performed within grant agreement No 870403 (project NEOROCKS) funded by the European Union’s Horizon 2020 research and innovation programme.</p> <p><strong>References</strong></p> <p>Koehn, Bruce W.; Bowell, Edward G.; Skiff, Brian A.; Sanborn, Jason J.; McLelland, Kyle P.; Pravec, Petr; et al. (October 2014). "Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2009 January through 2009 June". The Minor Planet Bulletin. <strong>41</strong> (4): 286–300</p> <p>Virkki, A. K. (23/04/2020) Planetary Radar Science Group. NAIC-Arecibo Observatory (http://www.naic.edu/~pradar/press/1998OR2.php)</p> <p>R.P.Binzel, F.E.DeMeo, E.V.Turtelboom, S.J.Bus, A.Tokunaga, T.H.Burbine, C.Lantz, D.Polishook, B.Carry, A.Morbidelli, M.Birlan, P.Vernazza, B.J.Burt, N.Moskovitz, S.M.Slivan, C.A.Thomas, A.S.Rivkin, M.D.Hicks, T.Dunn, V.Reddy, J.A.Sanchez, M.Granvik, T.Kohout, 2019, Compositional distributions and evolutionary processes for the near-Earth object population: Results from the MIT-Hawaii Near-Earth Object Spectroscopic Survey (MITHNEOS), Icarus, 324, 41.</p> <p>Warner, Brian D., Stephens, Robert D., Near-Earth Asteroid Lightcurve Analysis at the Center for Solar System Studies: 2019 December - 2020 April<strong>, </strong>2020<strong>,  </strong>The Minor Planet Bulletin (ISSN 1052-8091). Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers, Vol. 47, No. 3, pp. 200-213.</p> <p>Brian A. Skiff, Kyle P. McLelland, Jason J. Sanborn, Petr Pravec, Bruce W. Koehn, 2019,  Lowell observatory near-earth asteroid photometric survey (NEAPS): paper 4, Minor Planet Bulletin 46.</p>