Minor Planet Center: data processing challenges

2015 ◽  
Vol 10 (S318) ◽  
pp. 265-269
Author(s):  
Michael Rudenko
Keyword(s):  
Data Processing ◽  
Minor Planet ◽  
Time Interval ◽  
Minor Planets ◽  
Earth Object ◽  
Short Arc ◽  
Sheer Number

AbstractThe Minor Planet Center receives up to several million astrometric observations of minor planets and comets each month. Given the volume of observations, the sheer number of known objects against which to possibly match, the shortness of the time interval over which each object was likely observed, and the uncertainties in the positions, and occasionally possible errors in times, reported, a number of data processing challenges present themselves. These include: Identifying observations of objects reported as new with already known objects; linking together sets of observations from different nights which may belong to the same object; determining if a set of observations has been assigned to the wrong object; determining if an object with a very short arc is possibly a Near-Earth object; prioritizing newly discovered objects in order of need of follow up; and, efficiently matching one or more observations with known objects.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

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

2020 ◽  
Author(s):  
Monica Lazzarin ◽  
Fiorangela La Forgia ◽  
Alessandro Siviero ◽  
Paolo Ochner ◽  
Elisa Frattin ◽  
...  
Keyword(s):  
Rare Event ◽  
Reflectance Spectroscopy ◽  
Minor Planet ◽  
Minor Planets ◽  
The European Union ◽  
Horizon 2020 ◽  
Earth Asteroid ◽  
Radar Images ◽  
Earth Object ◽  
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>

scholarly journals Klet Observatory – European Contribution to Detecting and Tracking of Near Earth Objects

2011 ◽  
Vol 7 ◽  
pp. 107-116
Author(s):  
Miloš Tichý
Keyword(s):  
Ccd Camera ◽  
Human Society ◽  
Minor Planets ◽  
Earth Object ◽  
The Earth ◽  
Orbit Computation ◽  
Near Earth Asteroids ◽  
International Strategies ◽  
Near Earth Objects

Near Earth Object (NEO) research is an expanding field of astronomy. Is is important for solar system science and also for protecting human society from asteroid and comet hazard.  A near-Earth object (NEO) can be defined as an asteroid or comet that has a possibility of making an approach to the Earth, or possibly even collide with it. The discovery rate of current NEO surveys reflects progressive improvement in a number of technical areas. An integral part of NEO discovery is astrometric follow-up fundamental for precise orbit computation and for the reasonable judging of future close encounters with the Earth including possible impact solutions. A wide international cooperation is fundamental for NEO research.  The Klet Observatory (South Bohemia, Czech Republic) is aimed especially at the confirmation, early follow-up, long-arc follow-up and recovery of Near Earth Objects. It ranks among the world´s most prolific professional NEO follow-up programmes.  The first NEO follow-up programme started at Klet in 1993 using 0.57-reflector equipped with a small CCD camera. A fundamental upgrade was made in 2002 when the 1.06-m KLENOT telescope was put into regular operation. The KLENOT Telescope is the largest telescope in Europe used exclusively for observations of minor planets (asteroids) and comets and full observing time is dedicated to the KLENOT team.  Equipment, technology, software, observing strategy and results of both the Klet Observatory NEO Project between 1993-2010 and the first phase of the KLENOT Project from March 2002 to September 2008 are presented. They consist of thousands of precise astrometric measurements of Near Earth Objects and also three newly discovered Near Earth Asteroids.  Klet Observatory NEO activities as well as our future plans fully reflect international strategies and cooperation in the field of NEO studies.

scholarly journals From telescope to MPC: Organizing the minor planets

1996 ◽  
Vol 172 ◽  
pp. 153-164 ◽  
Author(s):  
B.G. Marsden
Keyword(s):  
Rapid Development ◽  
Computer Software ◽  
Minor Planet ◽  
Minor Planets ◽  
Oak Ridge ◽  
Star Catalogue ◽  
Ccd Observations ◽  
Guide Star ◽  
The University

Somewhat more than a century after its introduction for the purpose of discovering minor planets, photography is now rapidly giving way to the CCD as the technology of choice for observing these bodies. A CCD has been used in scanning mode in the University of Arizona's ‘Spacewatch’ program for the discovery of minor planets since as long ago as 1984 (Gehrels 1984, Gehrels et al. 1986), while a CCD in stare mode was first applied as a matter of routine to an established observing program for astrometric follow-up in 1989—that at the Oak Ridge Observatory in Massachusetts (McCrosky 1990). After its initial 1984–1986 success, Spacewatch was modified with the help of a larger CCD and improved computer software and with the adoption of the particular mission of searching for NEOs, or minor planets (and comets) that pass close to the earth (Rabinowitz 1991, Scotti 1994). The Oak Ridge program utilizes a 1.5-m reflector, and the first CCD observations were reduced using the Astrographic Catalogue, the mainstay of the Oak Ridge photographic program back to its inauguration in 1972, as well as of other older photographic programs in which the fields observed were significantly less than 1° across. Within months, the availability, on CD-ROMs, of the STScI Guide Star Catalogue (Villard 1989) effectively consigned the venerable AC to the scrap-heap, and the rapid development of ready-made and relatively inexpensive CCD systems (e.g., di Cicco 1992) has recently increased the volume of CCD astrometry considerably, allowing it to be conveniently and reliably carried out, even by amateur astronomers. At the present time, very nearly 50 percent of the astrometric observations, typically 6000, published each month in the Minor Planet Center's Minor Planet Circulars are obtained by means of a CCD.

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

scholarly journals Improving the dynamical reference frame through minor planet orbit correction using crossing point observations

1988 ◽  
Vol 128 ◽  
pp. 55-60
Author(s):  
Arthur L. Whipple ◽  
Raynor L. Duncombe ◽  
Paul D. Hemenway
Keyword(s):  
Computer Program ◽  
Reference Frame ◽  
Reference System ◽  
Hubble Space Telescope ◽  
Simulated Data ◽  
Minor Planet ◽  
Minor Planets ◽  
Space Telescope ◽  
Orbit Correction ◽  
Crossing Point

We have begun a program to establish a dynamical reference frame based on the motions of minor planets. The program will utilize observations from the Hubble Space Telescope, and will ultimately tie the HIPPARCOS reference system to a dynamical base. Thirty-four minor planets, 20 of which are suitable for observation with the Hubble Space Telescope, have been selected. Ground based observations, particularly crossing-point observations with long focus reflectors, have been initiated.A computer program to simultaneously solve for the corrections of the orbits of the 34 minor planets including the crossing-point observations, was successfully run. The observations are treated by the method of W. H. Jeffreys. Using simulated data, solutions with and without crossing point observations demonstrate the value of those observations to produce a homogeneous and coherent set of results.

scholarly journals Feasibility of Proton Beam Therapy as a Rescue Therapy in Heavily Pre-Treated Retinoblastoma Eyes

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1862
Author(s):  
Eva Biewald ◽  
Tobias Kiefer ◽  
Dirk Geismar ◽  
Sabrina Schlüter ◽  
Anke Manthey ◽  
...  
Keyword(s):  
Proton Beam ◽  
Rescue Therapy ◽  
Therapeutic Option ◽  
Proton Beam Therapy ◽  
External Beam Radiation ◽  
Time Interval ◽  
Beam Radiation ◽  
Primary Tumors ◽  
Increased Risk

Despite the increased risk of subsequent primary tumors (SPTs) external beam radiation (EBRT) may be the only therapeutic option to preserve a retinoblastoma eye. Due to their physical properties, proton beam therapy (PBT) offers the possibility to use the effectiveness of EBRT in tumor treatment and to decisively reduce the treatment-related morbidity. We report our experiences of PBT as rescue therapy in a retrospectively studied cohort of 15 advanced retinoblastoma eyes as final option for eye-preserving therapy. The average age at the initiation of PBT was 35 (14–97) months, mean follow-up was 22 (2–46) months. Prior to PBT, all eyes were treated with systemic chemotherapy and a mean number of 7.1 additional treatments. Indication for PBT was non-feasibility of intra-arterial chemotherapy (IAC) in 10 eyes, tumor recurrence after IAC in another 3 eyes and diffuse infiltrating retinoblastoma in 2 eyes. Six eyes (40%) were enucleated after a mean time interval of 4.8 (1–8) months. Cataract formation was the most common complication affecting 44.4% of the preserved eyes, yet 77.8% achieved a visual acuity of >20/200. Two of the 15 children treated developed metastatic disease during follow-up, resulting in a 13.3% metastasis rate. PBT is a useful treatment modality as a rescue therapy in retinoblastoma eyes with an eye-preserving rate of 60%. As patients are at lifetime risk of SPTs consistent monitoring is mandatory.

Abstract 1122‐000084: Does Intravenous Thrombolysis Promote Delayed Reperfusion After Incomplete Mechanical Thrombectomy?

2021 ◽  
Vol 1 (S1) ◽  
Author(s):  
Adnan Mujanovic ◽  
Christoph Kammer ◽  
Christoph C Kurmann ◽  
Lorenz Grunder ◽  
Morin Beyeler ◽  
...  
Keyword(s):  
Perfusion Imaging ◽  
Mechanical Thrombectomy ◽  
Intravenous Thrombolysis ◽  
Functional Independence ◽  
Considerable Proportion ◽  
Time Interval ◽  
Start Time ◽  
Vessel Occlusion ◽  
Stroke Registry

Introduction : The value of intravenous thrombolysis (IVT) in patients eligible for mechanical thrombectomy (MT) remains unclear. We hypothesized that pre‐treatment with and/or ongoing IVT may facilitate reperfusion of distal vessel occlusion after incomplete MT. We evaluated this potential association using follow‐up perfusion imaging. Methods : Retrospective observational analysis of our institution`s stroke registry included patients with incomplete reperfusion after MT, admitted between February 1, 2015 and December 8, 2020. Delayed reperfusion (DR) was defined as the absence of a persistent perfusion deficit on contrast‐enhanced perfusion imaging ⁓24h±12h after the intervention. The association between baseline parameters and the occurrence of DR was evaluated using a logistic regression analyses. To account for possible time‐dependent associations of IVT with DR, additional stratification sets were made based on different time windows between IVT start time and final angiography runs. Results : Among the 378 included patients (median age 73.5, 50.8% female), DR occurred in 226 (59.8%). Atrial fibrillation (aOR 2.53 [95% CI 1.34 ‐ 4.90]), eTICI score (aOR 3.79 [95% CI 2.71 ‐ 5.48] per TICI grade increase), and intervention‐to‐follow‐up time (aOR 1.08 [95% CI 1.04 ‐ 1.13] per hour delay) were associated with DR. Dichotomized IVT strata showed no association with DR (aOR 0.75 [95% CI 0.42 ‐ 1.33]), whereas shorter intervals between IVT start and end of the procedure showed a borderline significant association with DR (OR 2.24 [95% CI 0.98 ‐ 5.43, and OR 2.07 [95% 1.06 – 4.31], for 80 and 100 minutes respectively). Patients with DR had higher rates of functional independence (modified Rankin scale 0–2 at 90 days, DR: 63.3% vs PPD: 38.8%; p<0.01) and longer survival time (at 3 years, DR: 69.2% vs PPD: 45.8%; p = 0.001). Conclusions : There is weak evidence that IVT may favor DR after incomplete MT if the time interval between IVT administration and end of the procedure is short. In general, perfusion follow‐up imaging may constitute a suitable surrogate parameter for evaluating medical rescue strategies after incomplete MT, because a considerable proportion of patients do not experience DR, and there seems to be a close correlation with clinical outcomes.

scholarly journals Postoperative craniospinal radiotherapy of medulloblastoma in children and young adults

2003 ◽  
Vol 131 (5-6) ◽  
pp. 226-231
Author(s):  
Ivana Golubicic ◽  
Jelena Bokun ◽  
Marina Nikitovic ◽  
Jasmina Mladenovic ◽  
Milan Saric ◽  
...  
Keyword(s):  
High Risk ◽  
Brain Stem ◽  
Wilcoxon Test ◽  
Time Interval ◽  
Tumor Removal ◽  
Shunt Placement ◽  
Craniospinal Radiotherapy ◽  
Number Of Patients ◽  
Significant Difference

PURPOSE The aim of this study was: 1. to evaluate treatment results of combined therapy (surgery, postoperative craniospinal radiotherapy with or without chemotherapy) and 2. to assess factors affecting prognosis (extend of tumor removal, involvement of the brain stem, extent of disease postoperative meningitis, shunt placement, age, sex and time interval from surgery to start of postoperative radiotherapy). PATIENTS AND METHODS During the period 1986-1996, 78 patients with medulloblastoma, aged 1-22 years (median 8.6 years), were treated with combined modality therapy and 72 of them were evaluable for the study end-points. Entry criteria were histologically proven diagnosis, age under 22 years, and no history of previous malignant disease. The main characteristics of the group are shown in Table 1. Twenty-nine patients (37.2%) have total, 8 (10.3%) near total and 41 (52.5%) partial removal. Seventy-two of 78 patients were treated with curative intent and received postoperative craniospinal irradiation. Radiotherapy started 13-285 days after surgery (median 36 days). Only 13 patients started radiotherapy after 60 days following surgery. Adjuvant chemotherapy was applied in 63 (80.7%) patients. The majority of them (46 73%) received chemotherapy with CCNU and Vincristine. The survival rates were calculated with the Kaplan-Meier method and the differences in survival were analyzed using the Wilcoxon test and log-rank test. RESULTS The follow-up period ranged from 1-12 years (median 3 years). Five-year overall survival (OS) was 51% and disease-free survival (DFS) 47% (Graph 1). During follow-up 32 relapses occurred. Patients having no brain stem infiltration had significantly better survival (p=0.0023) (Graph 2). Patients with positive myelographic findings had significantly poorer survival compared to dose with negative myelographic findings (p=0.0116). Significantly poorer survival was found in patients with meningitis developing in the postoperative period, with no patient living longer than two years (p=0.0134) (Graph 3). By analysis of OS and DFS in relation to presence of the malignant cells in liquor, statistically significant difference, i. e. positive CSF cytology was not obtained, which was of statistical importance for survival (p=0.8207). Neither shunt placement nor shunt type showed any impact on survival (p=0.5307 and 0.7119, respectively). Children younger than three years had significantly poorer survival compared to those older than 16 years (p=0.0473). Although there was a better survival rate in females than in males this was not statistically significant (p=0.2386).The analysis results of treatment showed that significantly better survival occurred in patients in whom total or subtotal tumor removal was possible (p=0.0022) (Graph 4). Patients who started radiotherapy within two months after surgery have better survival, but again this was not statistically significant, probably due to the small number of patients receiving delayed radiotherapy (p=0.2231)(Graph5). CONCLUSION Based on this factors standard and high risk group could be defined. Combined chemotherapy should to be investigated particularly for high risk subgroup. Future research should be done to define new therapeutic modalities (gene therapy, compounds active in tumor antiangiogenesis etc).

scholarly journals Left atrial strain evaluation and prognostic value in constrictive pericarditis patients undergoing pericardiectomy

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
S Lo Presti ◽  
N Chan ◽  
Y Saijo ◽  
T Wang ◽  
A Klein
Keyword(s):  
Constrictive Pericarditis ◽  
Left Atrial ◽  
Multivariable Analysis ◽  
Time Interval ◽  
Clinical Tool ◽  
Left Atrial Strain ◽  
Endocardial Border ◽  
Valvular Surgery ◽  
All Cause Mortality

Abstract Background Left Atrial (LA) phasic volumes analyses is flawed with geometrical assumption requiring high endocardial border definition. LA strain analysis is an emergent technique that overcome some of these technical limitations. Prior studies of LA mechanics in pericardiectomy patients found improvement in LA strain at follow-up and manifested as symptomatic improvement, however their relationships with survival have not been investigated. Purpose We assessed LA strain before and after pericardiectomy and its association with all- cause mortality. Methods Consecutive patients with constrictive pericarditis who underwent pericardiectomy from 2000–2017 were retrospectively analyzed, analyzing pre-operative and post-operative (at 12 months) echocardiography. Exclusion criteria included atrial fibrillation, previous left sided valve surgery, concomitant valvular surgery at the index pericardiectomy, more than mild left sided valvulopathy and poor echocardiographic windows. Strain analyses was performed with Vector velocity imaging independent software. Univariate and multivariable analyses were utilized to identify factors associated with reduced survival. Results Amongst 190 patients included in the analyses, mean age was 58.5±12.7 years and 37 (19.5%) were female. The etiology of constriction was deemed idiopathic in 61.6% of the cases, median time interval surgery-postoperative echo was 67 days (IQR 6, 312 days). During median follow up of 3.3 years (IQR 0.73, 5.9 years) there were 37 deaths. After surgery, there was a significant decrease in LA reservoir, conduit and regional wall strains. (Table 1). Multivariable analysis demonstrated that postoperative 4C AL strain reservoir was independently associated with all-cause mortality (Table 2). Conclusions In pericardiectomy patients, postoperative 4C LA strain reservoir is independently associated with all-cause mortality. Perhaps, compensatory changes of septal and antero-posterior walls during constriction explain why after surgery these walls become less dynamic, negatively impacting the overall function. Overall, LA quantification and strains may become a useful clinical tool for risk stratification in pericardiectomy patients FUNDunding Acknowledgement Type of funding sources: None. Table 1. Left atrial variables. Table 2. All-cause mortality predictors

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