128383 (2004 JW52) is an Ordinary Jupiter Trojan Asteroid

The Jupiter Trojan asteroid 128383 (2004 JW52) was recently reported to have optical colors that are incongruous with its dynamical class. New and archival observations show that this is not the case. This is a reminder that we must always rule out the possibility that the Point-Spread Function of a minor planet is blended with that of a background sidereal source in survey images before its colors in the associated survey catalog can be considered reliable.

Mysterious Dust-emitting Object Orbiting TIC 400799224

We report the discovery of a unique object of uncertain nature—but quite possibly a disintegrating asteroid or minor planet—orbiting one star of the widely separated binary TIC 400799224. We initially identified the system in data from TESS Sector 10 via an abnormally shaped fading event in the light curve (hereafter “dips”). Follow-up speckle imaging determined that TIC 400799224 is actually two stars of similar brightness at 0.″62 separation, forming a likely bound binary with projected separation of ∼300 au. We cannot yet determine which star in the binary is host to the dips in flux. ASAS-SN and Evryscope archival data show that there is a strong periodicity of the dips at ∼19.77 days, leading us to believe that an occulting object is orbiting the host star, though the duration, depth, and shape of the dips vary substantially. Statistical analysis of the ASAS-SN data shows that the dips only occur sporadically at a detectable threshold in approximately one out of every three to five transits, lending credence to the possibility that the occulter is a sporadically emitted dust cloud. The cloud is also fairly optically thick, blocking up to 37% or 75% of the light from the host star, depending on the true host. Further observations may allow for greater detail to be gleaned as to the origin and composition of the occulter, as well as to a determination of which of the two stars comprising TIC 400799224 is the true host star of the dips.

Studying the fractal properties of Ceres

Currently, the asteroid Ceres belongs to small celestial bodies with the most well-known physical parameters. The study of the structural and real properties of Ceres is an urgent and modern task, the solution of which will make it possible to develop the evolutionary theory of a minor planet. In this work, the fractal properties of the dwarf planet Ceres were analyzed using data from the Dawn space mission. Using the expansion in a harmonic series in spherical functions the height parameters of the structural model of Ceres, a 3D model of Ceres was constructed. The analysis showed that the resulting system has a complex multiparameter fractal configuration. The study of such objects requires the use of harmonic multiparameter methods. Multivariate fractal analysis allows to represent systems similar to the Ceres model in the form of a spectrum of fractal dimensions. The advantage of fractal analysis is the ability to explore local areas of the physical surface. In this work, the Minkowski algorithm was used for this purpose. At the final stage, an overdetermined system was solved for various local areas of topocentric information in order to postulate a model that takes into account external measures. Fractal dimensions D are determined for local regions and the entire model of the planet. Fractal dimensions vary from 1.37 to 1.92 depending on the longitude and latitude of Ceres. The main results are as follows: 1) the structure of the Ceres surface varies more strongly in longitude; 2) the structure of Ceres is smoother in latitude; 3) the coefficient of self-similarity changes rather quickly in longitude, which indicates that different local regions of the minor planet were formed under the influence of various physical processes. It is necessary to emphasize that the resulting fractal dimensions are significantly scattered both in longitude and latitude of Ceres. This fact confirms the presence of a complex structure in the spatial model of a minor planet. This also applies to the actual physical surface of Ceres. The results of the work allow us to conclude that fractal modeling can give independent values of the fractal dimension both for the entire model of Ceres and for its local macrostructural regions.

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>

Astrometric observations of Near Earth Objects and Minor Planet Center

<p>NOAK Observatory, Stavraki (IAU code L02) Ioannina, Greece ([email protected])</p> <p><strong>Introduction</strong></p> <p>In this work, the astrometric observations of four asteroids will be presented which took place on 2019 from NOAK observatory located at Stavraki in Greece. The results and the procedure of submitting the measurements to MinorPlanetCenter will be discussed.</p> <p><strong>Abstract</strong></p> <p>Astrometry is the measurement of positions, parallaxes and proper motion of an astronomical body. Especially the astrometry of Near Earth Objects (NEO) demands great accuracy and the cooperation between the professional and amateur astronomers for better results. All these objects that need confirmation are listed in the Near Earth Object Confirmation Page (NEOCP) and in the Possible Comet Confirmation Page (PCCP) at the site of the Minor Planet Center (MPC). When an object is confirmed, then a Minor Planet Electronic Circular (MPES) is published, including observations, the observers details and the orbital elements of the object. Due to the high number of the objects that need confirmation is important to use all available telescopes to track them.</p> <p>My amateur observatory participates in the effort to record all these objects in the Solar System. The Observatory also conducts observations of various objects and other phenomena such as exoplanet transits contributing to the Ariel Space Mission with the Exoclock Project. However, the main goal of the observatory is to conduct asteroid and comet photometry and the methods, observations and results will be discussed in this presentation.</p> <p>The observatory is registered in IAU as L02, «NOAK Observatory, Stavraki», in the town of Ioannina, Greece.</p> <p><strong>Acknowledgements</strong></p> <p>I would like to thank Anastasia Kokori and Angelos Tsiaras for encouraging me to publish my work and for their advice. </p> <p><strong>References </strong></p> <p>[1] Minor Planet Center: https://www.minorplanetcenter.net/</p> <p>[2] Astrometrica: http://www.astrometrica.at/</p> <p>[3] Roger Dymock: Asteroids and Dwarf Planets</p> <p>[4] Brian D. Warner: A Practical Guide to Lightcurve Photometry and Analysis</p> <p>[5] Project Pluto: https://www.projectpluto.com/</p> <p>[6] NEODyS-2: https://newton.spacedys.com/</p> <p>[7] Center for Near Earth Objects Studies: https://cneos.jpl.nasa.gov/</p>

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>

THE GBOT ASTEROID SURVEY. FIRST YEARS: JAN 2015 - MAY 2018

The GBOT group is in charge of the Ground Based Optical Tracking ofthe Gaia satellite. In concrete terms, since the launch of Gaia, our task is to take every night, using ground based medium-class telescopes, short sequences of 10 or 20 images of the Gaia satellite close to its meridian transit. For this purpose, we mainly use the VLT Survey Telescope and the Liverpool Telescope. In these images, taken close to the Sun's opposition - since Gaia is in L2 - we observe many asteroids: between 30 and 100 every night, up to magnitude 22. In order to extract the astrometric positions as well as the magnitudes of these asteroids, we have developed semi-automatic methods, strategies and tools tailored explicitly for this daily task. In only three and a half years of operation, this system has allowed us to send to the Minor Planet Center the position and the photometry of about 20,000 asteroids, amongst which 9,000 are new objects. Here we describe all the aspects of the GBOT asteroid survey.

On a possibility of transfer of the planet troyans to centaurs

Jupiter Trojans and Neptune Trojans have been selected from the Minor Planet center catalog for 2020. Numerical calculations of the evolution of orbits on intervals of up to 1 million years have been carried out. It has been established that all discovered by today Neptune Trojans and the numbered Jupiter Trojans are unlikely to transfer into the Centaur population during the next hundreds of thousands of years.