Use of the semilinear method to predict the impact corridor on ground

Dimare, Linda; Vigna, Alessio Del; Cioci, Davide Bracali; Bernardi, Fabrizio

doi:10.1007/s10569-020-09959-3

Cited by 5 publications

(11 citation statements)

References 23 publications

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“…If a return containing impacting orbits is suitably densified, at least locally in a neighbourhood of the VI, the determination of the VI representative could be improved in such a way that the selected orbit is as close as possible to the VI centre. This turns out to be important when the VI representative is used as a starting point for further predictions, as it happens for the semilinear method presented in Dimare et al (2020) to compute the impact corridor of an Earth-impacting asteroid. More general algorithms for a local and possibly adaptive densification of the LOV sampling will be subject of future research.…”

Section: Discussionmentioning

confidence: 99%

Improving impact monitoring through Line Of Variations densification

Vigna

Guerra

Valsecchi

2020

Icarus

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We propose a densification algorithm to improve the Line Of Variations (LOV) method for impact monitoring, which can fail when the information is too little, as it may happen in difficult cases. The LOV method uses a 1-dimensional sampling to explore the uncertainty region of an asteroid. The close approaches of the sample orbits are grouped by time and LOV index, to form the so-called returns, and each return is analysed to search for local minima of the distance from the Earth along the LOV. The strong non-linearity of the problem causes the occurrence of returns with so few points that a successful analysis can be prevented. Our densification algorithm tries to convert returns with length at most 3 in returns with 5 points, properly adding new points to the original return. Due to the complex evolution of the LOV, this operation is not necessarily achieved all at once: in this case the information about the LOV geometry derived from the first attempt is exploited for a further attempt. Finally, we present some examples showing that the application of our method can have remarkable consequences on impact monitoring results, in particular about the completeness of the virtual impactors search.

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Section: Discussionmentioning

confidence: 99%

Improving impact monitoring through Line Of Variations densification

Vigna

Guerra

Valsecchi

2020

Icarus

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“…A part of this activity is the prediction of the impact location of a potential impactor, especially when the associated impact probability is high. A method to predict the impact corridor of an asteroid has been developed in Dimare et al (2020), by which the impact region is given by semilinear boundaries on the impact surface at a given altitude above the Earth and corresponding to different confidence levels. The algorithm is conceived to be a continuation of the impact monitoring algorithm at the basis of the clomon-2 system, since the semilinear method requires a nominal orbit obtained by full differential corrections and an impacting orbit, 5 as provided by the LOV method (Milani et al 2005a).…”

Section: Introductionmentioning

confidence: 99%

“…Section 4 contains the results of our method applied to the impacted asteroids 2008 TC 3 , 2014 AA, 2018 LA, and 2019 MO. When possible, we also compare the impact regions with those computed with the semilinear method (Dimare et al 2020) and with a Monte Carlo simulation. Lastly, Sect.…”

Section: Introductionmentioning

confidence: 99%

The Manifold Of Variations: impact location of short-term impactors

Vigna

Dimare²,

Cioci³

2021

Celest Mech Dyn Astr

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The interest in the problem of small asteroids observed shortly before a deep close approach or an impact with the Earth has grown a lot in recent years. Since the observational dataset of such objects is very limited, they deserve dedicated orbit determination and hazard assessment methods. The currently available systems are based on the systematic ranging, a technique providing a two-dimensional manifold of orbits compatible with the observations, the so-called Manifold Of Variations. In this paper we first review the Manifold Of Variations method, to then show how this set of virtual asteroids can be used to predict the impact location of short-term impactors, and compare the results with those of already existent methods.

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“…• 2019MO: discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) Mauna Loa observatory on 22 June 2019 at 9:49 (less than 12 h before impact) this object was a small (4-6 metres in diameter) Apollo-type Near-Earth Asteroid. It was at first registered in the NEOCP with four observations and pointed out as an imminent impactor by NEOScan, but the low score assigned prevented prompt follow-up, so that three additional observations from the Pan-STARRS2 images were recovered only after the impact [21], a procedure known as "precovery". In Figure 3 we show the output of Tool 1 for the first tracklet of four observations and for the seven observations "precovered" tracklet.…”

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confidence: 99%

“…The kernel of the software is the program resret3tp, that takes as input the output files of cateph2 and performs a complete Target Plane (TP) analysis (see Farnocchia et al [2] for details) for each orbit, computing stretching and width w (i.e., the semimajor and semiminor axes in the ellipsoid approximation, as defined in Dimare et al [21]) of the Confidence Region. Close approaches are then divided into showers (i.e., sorted by date), and for each VA, lists of consecutive indexes (known as "returns") are produced.…”

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confidence: 99%

New Tools for the Optimized Follow-Up of Imminent Impactors

Mochi

Tommei

2021

Universe

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The solar system is populated with, other than planets, a wide variety of minor bodies, the majority of which are represented by asteroids. Most of their orbits are comprised of those between Mars and Jupiter, thus forming a population named Main Belt. However, some asteroids can run on trajectories that come close to, or even intersect, the orbit of the Earth. These objects are known as Near Earth Asteroids (NEAs) or Near Earth Objects (NEOs) and may entail a risk of collision with our planet. Predicting the occurrence of such collisions as early as possible is the task of Impact Monitoring (IM). Dedicated algorithms are in charge of orbit determination and risk assessment for any detected NEO, but their efficiency is limited in cases in which the object has been observed for a short period of time, as is the case with newly discovered asteroids and, more worryingly, imminent impactors: objects due to hit the Earth, detected only a few days or hours in advance of impacts. This timespan might be too short to take any effective safety countermeasure. For this reason, a necessary improvement of current observation capabilities is underway through the construction of dedicated telescopes, e.g., the NEO Survey Telescope (NEOSTEL), also known as “Fly-Eye”. Thanks to these developments, the number of discovered NEOs and, consequently, imminent impactors detected per year, is expected to increase, thus requiring an improvement of the methods and algorithms used to handle such cases. In this paper we present two new tools, based on the Admissible Region (AR) concept, dedicated to the observers, aiming to facilitate the planning of follow-up observations of NEOs by rapidly assessing the possibility of them being imminent impactors and the remaining visibility time from any given station.

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Use of the semilinear method to predict the impact corridor on ground

Cited by 5 publications

References 23 publications

Improving impact monitoring through Line Of Variations densification

Improving impact monitoring through Line Of Variations densification

The Manifold Of Variations: impact location of short-term impactors

New Tools for the Optimized Follow-Up of Imminent Impactors

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