Data on 824 fireballs observed by the digital cameras of the European Fireball Network in 2017-2018. II. Analysis of orbital and physical properties of centimeter-sized meteoroids

Meteoroids impacting the Earth on a daily basis are fragments of asteroids and comets. By studying fireballs produced during their disintegration in the atmosphere, we can gain information about their source regions and the properties of their parent bodies. In this work, data on 824 fireballs presented in an accompanying paper and catalog are used. We propose a new empirical parameter for the classification of the physical properties of meteoroids, based on the maximum dynamic pressure suffered by the meteoroid in the atmosphere. We then compare the physical and orbital properties of meteoroids. We find that aphelion distance is a better indicator of asteroidal origin than the Tisserand parameter. Meteoroids with aphelia lower than 4.9 AU are mostly asteroidal, with the exception of the Taurids and alpha Capricornids associated with the comets 2P/Encke and 169P/NEAT, respectively. We found another population of strong meteoroids of probably asteroidal origin on orbits with either high eccentricities or high inclinations, and aphelia up to ~ 7 AU. Among the meteoroid streams, the Geminids and eta Virginids are the strongest, and Leonids and alpha Capricornids the weakest. We found fine orbital structures within the Geminid and Perseid streams. Four minor meteoroid streams from the working list of the International Astronomical Union were confirmed. No meteoroid with perihelion distance lower than 0.07 AU was detected. Spectra are available for some of the fireballs, and they enabled us to identify several iron meteoroids and meteoroids deficient in sodium. Recognition and frequency of fireballs leading to meteorite falls is also discussed.Comment: accepted in Astronomy and Astrophysic

The desert fireball network: A new camera network in the western Australian Nullarbor

Accepted versio

OT 060420: A Seemingly Optical Transient Recorded by All-Sky Cameras

We report on a ~5th magnitude flash detected for approximately 10 minutes by two CONCAM all-sky cameras located in Cerro Pachon - Chile and La Palma - Spain. A third all-sky camera, located in Cerro Paranal - Chile did not detect the flash, and therefore the authors of this paper suggest that the flash was a series of cosmic-ray hits, meteors, or satellite glints. Another proposed hypothesis is that the flash was an astronomical transient with variable luminosity. In this paper we discuss bright optical transient detection using fish-eye all-sky monitors, analyze the apparently false-positive optical transient, and propose possible causes to false optical transient detection in all-sky cameras.Comment: 7 figures, 3 tables, accepted PAS

Data on 824 fireballs observed by the digital cameras of the European Fireball Network in 2017-2018. I. Description of the network, data reduction procedures, and the catalog

A catalog of 824 fireballs (bright meteors), observed by a dedicated network of all-sky digital photographic cameras in central Europe in the years 2017-2018 is presented. The status of the European Fireball Network, established in 1963, is described. The cameras collect digital images of meteors brighter than an absolute magnitude of about -2 and radiometric light curves with a high temporal resolution of those brighter than a magnitude ~ -4. All meteoroids larger than 5 grams, corresponding to sizes of about 2 cm, are detected regardless of their entry velocity. High-velocity meteoroids are detected down to masses of about 0.1 gram. The largest observed meteoroid in the reported period 2017-2018 had a mass of about 100 kg and a size of about 40 cm. The methods of data analysis are explained and all catalog entries are described in detail. The provided data include the fireball date and time, atmospheric trajectory and velocity, the radiant in various coordinate systems, heliocentric orbital elements, maximum brightness, radiated energy, initial and terminal masses, maximum encountered dynamic pressure, physical classification, and possible shower membership. Basic information on the fireball spectrum is available for some bright fireballs (apparent magnitude < -7). A simple statistical evaluation of the whole sample is provided. The scientific analysis is presented in an accompanying paper.Comment: accepted in Astronomy and Astrophysic

The 2014 KCG Meteor Outburst: Clues to a Parent Body

The Kappa Cygnid (KCG) meteor shower exhibited unusually high activity in 2014, producing ten times the typical number of meteors. The shower was detected in both radar and optical systems and meteoroids associated with the outburst spanned at least five decades in mass. In total, the Canadian Meteor Orbit Radar, European Network, and NASA All Sky and Southern Ontario Meteor Network produced thousands of KCG meteor trajectories. Using these data, we have undertaken a new and improved characterization of the dynamics of this little-studied, variable meteor shower. The Cygnids have a di use radiant and a significant spread in orbital characteristics, with multiple resonances appearing to play a role in the shower dynamics. We conducted a new search for parent bodies and found that several known asteroids are orbitally similar to the KCGs. N-body simulations show that the two best parent body candidates readily transfer meteoroids to the Earth in recent centuries, but neither produces an exact match to the KCG radiant, velocity, and solar longitude. We nevertheless identify asteroid 2001 MG1 as a promising parent body candidate

The problems associated with the monitoring of complex workplace radiation fields at European high-energy accelerators and thermonuclear fusion facilities

The European Commission is funding within its Sixth Framework Programme a three-year project (2005-2007) called CONRAD, COordinated Network for RAdiation Dosimetry. The organisational framework for this project is provided by the European Radiation Dosimetry Group EURADOS. One task within the CONRAD project, Work Package 6 (WP6), was to provide a report outlining research needs and research activities within Europe to develop new and improved methods and techniques for the characterisation of complex radiation fields at workplaces around high-energy accelerators, but also at the next generation of thermonuclear fusion facilities. The paper provides an overview of the report, which will be available as CERN Yellow Repor

Keeping the Vimentin Network under Control: Cell–Matrix Adhesion–associated Plectin 1f Affects Cell Shape and Polarity of Fibroblasts

Mature focal adhesions and fibrillar adhesions act as anchorage sites for vimentin filaments, with plectin isoform 1f being the crucial linker protein. Plectin serves as a nucleation and assembly center for the de novo formation of vimentin networks. Anchored vimentin creates a resilient cage-like core structure that affects cell shape

Ataxin-3 Plays a Role in Mouse Myogenic Differentiation through Regulation of Integrin Subunit Levels

BACKGROUND: During myogenesis several transcription factors and regulators of protein synthesis and assembly are rapidly degraded by the ubiquitin-proteasome system (UPS). Given the potential role of the deubiquitinating enzyme (DUB) ataxin-3 in the UPS, and the high expression of the murine ataxin-3 homolog in muscle during embryogenesis, we sought to define its role in muscle differentiation. METHODOLOGY/PRINCIPAL FINDINGS: Using immunofluorescence analysis, we found murine ataxin-3 (mATX3) to be highly expressed in the differentiated myotome of E9.5 mouse embryos. C2C12 myoblasts depleted of mATX3 by RNA interference exhibited a round morphology, cell misalignment, and a delay in differentiation following myogenesis induction. Interestingly, these cells showed a down-regulation of alpha5 and alpha7 integrin subunit levels both by immunoblotting and immunofluorescence. Mouse ATX3 was found to interact with alpha5 integrin subunit and to stabilize this protein by repressing its degradation through the UPS. Proteomic analysis of mATX3-depleted C2C12 cells revealed alteration of the levels of several proteins related to integrin signaling. CONCLUSIONS: Ataxin-3 is important for myogenesis through regulation of integrin subunit levels.This work was financed by the Fundacao para a Ciencia e a Tecnologia (FCT) (POCI/SAU-MMO/60412/2002) and by National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH/NINDS) grant RO1 NS038712 to HLP. MCC, FB, AJR, and RJT were supported by the FCT fellowships (SFRH/BD/9759/2003 and SFRH/BPD/28560/2006), (SFRH/BPD/17368/2004), (SFRH/BD/17066/2004), (SFRH/BD/29947/2006), respectively. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Observational evidence of high-altitude meteor trail from radar interferometer

Whether radar meteor echoes occur at high altitudes (above ~130 km) in the Earth's atmosphere is a long-standing question within the meteor radar community. Using observations from the Sanya VHF coherent radar interferometer during 11 July to 10 August 2013, we have found a new class of range-spread high-altitude meteor trail echoes (HAMEs), some of which appeared at ~170 km altitude lasting more than 10 s. A statistical analysis on the local time dependence of the identified HAME events shows a maximum around 00–04 LT. The results imply that there could be much more meteor mass input due to meteoroid sputtering at high altitudes in the Earth's atmosphere than previously thought.Guozhu Li, Baiqi Ning, Weixing Wan, I. M. Reid, Lianhuan Hu, Xinan Yue, J. P. Younger and B.K. Dolma