ترغب بنشر مسار تعليمي؟ اضغط هنا

Link between the Potentially Hazardous Asteroid (86039) 1999 NC43 and the Chelyabinsk meteoroid tenuous

186   0   0.0 ( 0 )
 نشر من قبل Vishnu Reddy
 تاريخ النشر 2015
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We explored the statistical and compositional link between Chelyabinsk meteoroid and potentially hazardous asteroid (86039) 1999 NC43 to investigate their proposed relation proposed by Boroviv{c}ka et al. (2013). Using detailed computation we confirm that the orbit of the Chelyabinsk impactor is anomalously close to 1999 NC43. We find about (1-3) x 10-4 likelihood of that to happen by chance. Taking the standpoint that the Chelyabinsk impactor indeed separated from 1999 NC43 by a cratering or rotational fission event, we run a forward probability calculation, which is an independent statistical test. However, we find this scenario is unlikely at the about (10-3 -10-2) level. We also verified compositional link between Chelyabinska and 1999NC43. Mineralogical analysis of Chelyabinsk (LL chondrite) and (8) Flora (the largest member of the presumed LL chondrite parent family) shows that their olivine and pyroxene chemistries are similar to LL chondrites. Similar analysis of 1999 NC43 shows that its olivine and pyroxene chemistries are more similar to L chondrites than LL chondrites (like Chelyabinsk). We also took photometric observations of 1999 NC43 over 54 nights during two apparitions (2000, 2014). The lightcurve of 1999 NC43 resembles simulated lightcurves of tumblers in Short-Axis Mode with the mean wobbling angle 20-30 deg. While, a mechanism of the non-principal axis rotation excitation is unclear, we can rule out the formation of asteroid in disruption of its parent body as a plausible cause, as it is unlikely that the rotation of an asteroid fragment from catastrophic disruption would be nearly completely halted. Considering all these facts, we find the proposed link between the Chelyabinsk meteoroid and the asteroid 1999 NC43 to be unlikely.



قيم البحث

اقرأ أيضاً

The physical characterization of potentially hazardous asteroids (PHAs) is important for impact hazard assessment and evaluating mitigation options. Close flybys of PHAs provide an opportunity to study their surface photometric and spectral propertie s that enable identification of their source regions in the main asteroid belt. We observed PHA (357439) 2004 BL86 during a close flyby of the Earth at a distance of 1.2 million km (0.0080 AU) on January 26, 2015, with an array of ground-based telescopes to constrain its photometric and spectral properties. Lightcurve observations showed that the asteroid was a binary and subsequent radar observations confirmed the binary nature and gave a primary diameter of 300 meters and a secondary diameter of 50-100 meters. Our photometric observations were used to derive the phase curve of 2004 BL86 in the V-band. Two different photometric functions were fitted to this phase curve, the IAU H-G model (Bowell et al. 1989) and the Shevchenko model (Shevchenko 1996). From the fit of the H-G function we obtained an absolute magnitude H=19.51+/-0.02 and a slope parameter G=0.34+/-0.02. The Shevchenko function yielded an absolute magnitude of H=19.03+/-0.07 and a phase coefficient b=0.0225+/-0.0006. The phase coefficient was used to calculate the geometric albedo (Ag) using the relationship found by Belskaya and Schevchenko (2000), obtaining a value of Ag=40+/-8% in the V-band. With the geometric albedo and the absolute magnitudes derived from the H-G and the Shevchenko functions we calculated the diameter (D) of 2004 BL86, obtaining D=263+/-26, and D=328+/-35 meters, respectively. 2004 BL86 spectral band parameters and pyroxene chemistry are consistent with non-cumulate eucrite meteorites.
Potentially hazardous asteroids (PHAs) represent a unique opportunity for physical characterization during their close approaches to Earth. The proximity of these asteroids makes them accessible for sample-return and manned missions, but could also r epresent a risk for life on Earth in the event of collision. Therefore, a detailed mineralogical analysis is a key component in planning future exploration missions and developing appropriate mitigation strategies. In this study we present near-infrared spectra (0.7-2.55 microns) of PHA (214869) 2007 PA8 obtained with the NASA Infrared Telescope Facility during its close approach to Earth on November 2012. The mineralogical analysis of this asteroid revealed a surface composition consistent with H ordinary chondrites. In particular, we found that the olivine and pyroxene chemistries of 2007 PA8 are Fa18(Fo82) and Fs16, respectively. The olivine-pyroxene abundance ratio was estimated to be 47%. This low olivine abundance and the measured band parameters, close to the H4 and H5 chondrites, suggest that the parent body of 2007 PA8 experienced thermal metamorphism before being catastrophically disrupted. Based on the compositional affinity, proximity to the J5:2 resonance, and estimated flux of resonant objects we determined that the Koronis family is the most likely source region for 2007 PA8.
We present a fireball detected in the night sky over Kyoto, Japan on UT 2017 April 28 at ${rm 15^{h},58^{m},19^{s}}$ by the SonotaCo Network. The absolute visual magnitude is $M_{rm v}$=$-$4.10$pm$0.42mag. Luminous light curves obtain a meteoroid mas s $m$=29$pm$1g, corresponding to the size $a_{rm s}$=2.7$pm$0.1cm. Orbital similarity assessed by D-criterions (cf. $D_{rm SH}$=0.0079) has identified a likely parent, the binary near-Earth asteroid (164121) 2003 YT$_1$. The suggested binary formation process is a YORP-driven rotational disintegration (Pravec & Harris 2007). The asynchronous state indicates the age of $<$10$^4$yr, near or shorter than the upper limit to meteoroid stream lifetime. We examine potential dust production mechanisms for the asteroid, including rotational instability, resurfacing, impact, photoionization, radiation pressure sweeping, thermal fracture and sublimation of ice. We find some of them capable of producing the meteoroid-scale particles. Rotational instability is presumed to cause mass shedding, in consideration of the recent precedents (e.g. asteroid (6478) Gault), possibly releasing mm-cm scale dust particles. Impacts by micrometeorites with size $simeq$1mm could be a trigger for ejecting the cm-sized particles. Radiation pressure can sweep out the mm-sized dust particles, while not sufficient for the cm-sized. For the other mechanisms, unprovable or unidentified. The feasibility in the parental aspect of 2003 YT$_1$ is somewhat reconciled with the fireball observation, yielding an insight into how we approach potentially hazardous objects.
136 - F. De Luise , D. Perna , E. Dotto 2007
In this paper we present the observational campaign carried out at ESO NTT and VLT in April and May 2006 to investigate the nature and the structure of the Near Earth Object (144898) 2004 VD17. In spite of a great quantity of dynamical information, a ccording to which it will have a close approach with the Earth in the next century, the physical properties of this asteroid are largely unknown. We performed visible and near--infrared photometry and spectroscopy, as well as polarimetric observations. Polarimetric and spectroscopic data allowed us to classify 2004 VD17 as an E-type asteroid. A good agreement was also found with the spectrum of the aubrite meteorite Mayo Belwa. On the basis of the polarimetric albedo (p_v=0.45) and of photometric data, we estimated a diameter of about 320 m and a rotational period of about 2 hours. The analysis of the results obtained by our complete survey have shown that (144898) 2004 VD17 is a peculiar NEO, since it is close to the breakup limits for fast rotator asteroids, as defined by Pravec and Harris (2000). These results suggest that a more robust structure must be expected, as a fractured monolith or a rubble pile in a strength regime (Holsapple 2002).
This is an overview of recent research on meteors and the parent bodies from which they are produced. While many meteor showers result from material ejected by comets, two out of the three strongest annual showers (the Geminids and the Quadrantids) a re associated with objects whose physical properties are apparently those of asteroids. In the last decades dynamical and observational studies have confirmed the existence of a number of Asteroid-Meteoroid Complexes, comprising streams and several macroscopic, split fragments. Spectroscopy of meteor showers has been utilized to investigate the perihelion-dependent thermal alteration while in interplanetary space. In this chapter, we review characteristics of the complexes, including those of some minor streams. The scientific interest is to trace the physical and dynamical properties of the complexes back to the evolutionary pathways to learn about the variety of production processes of meteoroids to form streams. We also discuss open questions in the field for the next decade.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا