2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites

Aims. 2P/Encke is a short period comet that was discovered in 1786 and has been extensively observed and studied for more than 200years. The Taurid meteoroid stream has long been linked with 2P/Encke owing to a good match of their orbital elements, even thoughthe comet’s activity is not strong enough to explain the number of observed meteors. Various small near-Earth objects (NEOs) havebeen discovered with orbits that can be linked to 2P/Encke and the Taurid meteoroid stream. Maribo and Sutter’s Mill are CM typecarbonaceous chondrite that fell in Denmark on January 17, 2009 and April 22, 2012, respectively. Their pre-atmospheric orbits placethem in the middle of the Taurid meteoroid stream, which raises the intriguing possibility that comet 2P/Encke could be the parentbody of CM chondrites.
Methods. To investigate whether a relationship between comet 2P/Encke, the Taurid complex associated NEOs, and CM chondritesexists, we performed photometric and spectroscopic studies of these objects in the visible wavelength range. We observed 2P/Enckeand 10 NEOs on August 2, 2011 with the FORS instrument at the 8.2 m Very Large Telescope on Cerro Paranal (Chile).
Results. Images in the R filter, used to investigate the possible presence of cometary activity around the nucleus of 2P/Encke andthe NEOs, show that no resolved coma is present. None of the FORS spectra show the 700 nm absorption feature due to hydratedminerals that is seen in the CM chondrite meteorites. All objects show featureless spectra with moderate reddening slopes at λ < 800nm. Apart for 2003 QC10 and 1999 VT25, which show a flatter spectrum, the spectral slope of the observed NEOs is compatible withthat of 2P/Encke. However, most of the NEOs show evidence of a silicate absorption in lower S/N data at λ > 800 nm, which is notseen in 2P/Encke, which suggests that they are not related.
Conclusions. Despite similar orbits, we find no spectroscopic evidence for a link between 2P/Encke, the Taurid complex NEOs andthe Maribo and Sutter’s Mill meteorites. However, we cannot rule out a connection to the meteorites either, as the spectral differencesmay be caused by secondary alteration of the surfaces of the NEOs. 

Words and things: souvenirs of over-site/over-sight for place-making

This paper addresses the problem of making things in a given place (Qatar), and asks how anticipations and memories of place contribute to practice-based manoeuvres of place-making. Flying across time zones and travelling through sites suggests aspects of place-making that would draw upon both a notion of meteorites coming to earth and an awareness of the sensory consequences of global travelling. What this experience also suggests is an ‘over-sight’ (‘over-site’) in how travellers remember a place for themselves, and how they re-member it for others in the form of souvenirs. Going to a place might often default to an envisioning of pre-emptive or imaginary souvenirs in anticipation of the destination; thinking about what a place might be like is hard to separate from what we think we will eventually take away from it. Thus, the idea to be explored is how we might ‘make in to place’ as much as we ‘make something in-place,’ which perhaps results in ‘making some thing into a place’. Etymologically, souvenir already suggests this in its derivation from Old French: ‘to remember, come to mind.’ How does one ‘come to remembering’ in a place that, like all planetary places, will always be both global and local? Perhaps it depends on how one lands in a place…. Meteoroids remain in orbit around a place: nascent souvenirs always above the horizon, un-made place-makings. Meteors come closer to landing but still, by definition, burn up in the atmospheres of the new place. Meteorites, though, land: they suggest what we mean by the human element of ‘makings in-/to place.’ Travelling from somewhere, to somewhere yet to be fully determined, meteorites (people and/or words and/or senses) reflect the dispersion and compression of sensory (thing-based) and word-based experiences of place. Drawing on the work of Paul Hopper, Paul Carter, Gilles Deleuze and Félix Guattari, Michel Serres, William Desmond and Julia Kristeva, the paper concludes that words evoke a place in which the present might take place, and that the senses evoke a present in which place might take place.

A influência da matemática nas regras para a direção do espírito e em o discurso do método

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The remarkable solar twin HIP 56948: a prime target in the quest for other Earths

Context. The Sun shows abundance anomalies relative to most solar twins. If the abundance peculiarities are due to the formation of inner rocky planets, that would mean that only a small fraction of solar type stars may host terrestrial planets. Aims. In this work we study HIP 56948, the best solar twin known to date, to determine with an unparalleled precision how similar it is to the Sun in its physical properties, chemical composition and planet architecture. We explore whether the abundances anomalies may be due to pollution from stellar ejecta or to terrestrial planet formation. Methods. We perform a differential abundance analysis (both in LTE and NLTE) using high resolution (R similar to 100 000) high S/N (600-650) Keck HIRES spectra of the Sun (as reflected from the asteroid Ceres) and HIP 56948. We use precise radial velocity data from the McDonald and Keck observatories to search for planets around this star. Results. We achieve a precision of sigma less than or similar to 0.003 dex for several elements. Including errors in stellar parameters the total uncertainty is as low as sigma similar or equal to 0.005 dex (1%), which is unprecedented in elemental abundance studies. The similarities between HIP 56948 and the Sun are astonishing. HIP 56948 is only 17 +/- 7 K hotter than the Sun, and log g, [Fe/H] and microturbulence velocity are only +0.02 +/- 0.02 dex, +0.02 +/- 0.01 dex and +0.01 +/- 0.01 km s(-1) higher than solar, respectively. Our precise stellar parameters and a differential isochrone analysis shows that HIP 56948 has a mass of 1.02 +/- 0.02 M-circle dot and that it is similar to 1 Gyr younger than the Sun, as constrained by isochrones, chromospheric activity, Li and rotation. Both stars show a chemical abundance pattern that differs from most solar twins, but the refractory elements (those with condensation temperature T-cond greater than or similar to 1000 K) are slightly (similar to 0.01 dex) more depleted in the Sun than in HIP 56948. The trend with T-cond in differential abundances (twins -HIP 56948) can be reproduced very well by adding similar to 3 M-circle plus of a mix of Earth and meteoritic material, to the convection zone of HIP 56948. The element-to-element scatter of the Earth/meteoritic mix for the case of hypothetical rocky planets around HIP 56948 is only 0.0047 dex. From our radial velocity monitoring we find no indications of giant planets interior to or within the habitable zone of HIP 56948. Conclusions. We conclude that HIP 56948 is an excellent candidate to host a planetary system like our own, including the possible presence of inner terrestrial planets. Its striking similarity to the Sun and its mature age makes HIP 56948 a prime target in the quest for other Earths and SETI endeavors.

All-sky Meteor Orbit System AMOS and preliminary analysis of three unusual meteor showers

All-sky Meteor Orbit System (AMOS) is a semi-autonomous video observatory for detection of transient events on the sky, mostly the meteors. Its hardware and software development and permanent placement on several locations in Slovakia allowed the establishment of Slovak Video Meteor Network (SVMN) monitoring meteor activity above the Central Europe. The data reduction, orbital determination and additional results from AMOS cameras–the SVMN database– as well as from observational expeditions on Canary Islands and in Canada provided dynamical and physical data for better understanding of mutual connections between parent bodies of asteroids and comets and their meteoroid streams. We present preliminary results on exceptional and rare meteor streams such as September ε Perseids (SPE) originated from unknown long periodic comet on a retrograde orbit, suspected asteroidal meteor stream of April α Comae Berenicids (ACO) in the orbit of meteorites Příbram and Neuschwanstein and newly observed meteor stream Camelopardalids (CAM) originated from Jupiter family comet 209P/Linear.

Aurora boreal observada en Valencia en la noche del dia cinco de marzo de ... 1764

Sign. : A10

Quarterly progress report on a study of meteoroid impact phenomena,

"National Aeronautics and Space Administration. Contract no. NAS 3-2121."

Meteor burst communication system : Alaska winter field test program /

"NOAA--S/T 76-2105"

Beobachtungn über die sternschnuppen angestellt auf den sternwarten zu Göttingen und Münster, nebst daraus abgeleiteten resultaten.

Inaug.-dis.--Göttingen.

An introduction to the study of meteorites, with a list of meteorites represented in the collection on Jan 1, 1904.

Mode of access: Internet.