8,332 research outputs found
Early evolution of disrupted asteroid P/2016 G1 (PANSTARRS)
We present deep imaging observations of activated asteroid P/2016 G1
(PANSTARRS) using the 10.4m Gran Telescopio Canarias (GTC) from late April to
early June 2016. The images are best interpreted as the result of a relatively
short-duration event with onset about days before
perihelion (i.e., around 10th February, 2016), starting sharply and decreasing
with a days (Half-width at half-maximum, HWHM). The
results of the modeling imply the emission of 1.710 kg of
dust, if composed of particles of 1 micrometer to 1 cm in radius, distributed
following a power-law of index --3, and having a geometric albedo of 0.15. A
detailed fitting of a conspicuous westward feature in the head of the
comet-like object indicates that a significant fraction of the dust was ejected
along a privileged direction right at the beginning of the event, which
suggests that the parent body has possibly suffered an impact followed by a
partial or total disruption. From the limiting magnitude reachable with the
instrumental setup, and assuming a geometric albedo of 0.15 for the parent
body, an upper limit for the size of possible fragment debris of 50 m in
radius is derived.Comment: Accepted by ApJ Letter
Dust loss from activated asteroid P/2015 X6
We present observations and dust tail models of activated asteroid P/2015 X6
from deep imaging data acquired at the 10.4m Gran Telescopio Canarias (GTC)
from mid-December 2015 to late January 2016. The results of the modeling
indicate that the asteroid has undergone a sustained dust loss over a two-month
or longer period. The dust parameters, derived from multidimensional fits of
the available images, are compatible with either ice sublimation or rotational
instability processes. An impulsive event, as it could be associated to an
impact with another body, is less likely. A power-law distribution of
particles, with minimum and maximum radius of 1 m and 1 cm, and power
index of --3.3 is found to be consistent with the observations. Depending on
the ejection velocity model adopted, the particle velocities are found in the
0.3 to 10 m s range. The activation time was between 18-26 days before
discovery. The total ejected mass from that time to the most recent observation
is in the range 5-910 kg. No dust features giving indication of
past activity earlier than the activation time have been observed.Comment: Accepted by ApJ, May 15th 201
On the dust environment of Main-Belt Comet 313P/Gibbs
We present observations carried out using the 10.4 m Gran Telescopio Canarias
and an interpretative model of the dust environment of activated asteroid
313P/Gibbs. We discuss three different models relating to different values of
the dust parameters, i.e, dust loss rate, maximum and minimum sizes of
particles, power index of the size distribution, and emission pattern. The best
model corresponds with an isotropic emission of particles which started on
August 1st. The size of grains were in the range of m, with
velocities for 100 m particles between ms, with a dust
production rate in the range of kgs. The dust tails'
brightness and morphology are best interpreted in terms of a model of sustained
and low dust emission driven by water-ice sublimation, spanning since 2014
August 1st, and triggered by a short impulsive event. This event produced an
emission of small particles of about 0.1 m with velocities of 4
ms. From our model we deduce that the activity of this Main-Belt
Comet continued for, at least, four months, since activation.Comment: 14 pages, 4 figures, 2 tables. Accepted for publication in The
Astrophysical Journa
Grammarians and academies. Towards a sociology of linguistic knowledge
En este trabajo se describen los presupuestos ideológicos que informan la actividad de los gramáticos normativistas y de las instituciones, principalmente las academias de las lenguas, que oficializan dicha actividad cuyo fin es la implantación de un determinado modelo de lengua basado en la variedad lingüÃstica de la clase dominante. Se hace ver que este modelo de lengua se fundamenta en una concepción filológica que procede de la Antigüedad Clásica y que esta visión distorsiona algunas de las propiedades esenciales de las lenguas naturales humanas y, por tanto, supone una dificultad para el progreso del conocimiento cientÃfico de las lenguas naturales.This article discusses the ideological background of
the linguistic activity of grammarians and academies. It is shown
that the purpose of this activity consists in establishing a language
model based on the linguistic variety of the dominant class.
This language model shows a philological conception inherited
from the Ancient Antiquity that distorts some of the fundamental
properties of natural human languages and, therefore, thwarts
an adequate progress in the scientific description of natural
languages
The dust environment of Main-Belt Comet P/2012 T1 (PANSTARRS)
Main-Belt Comet P/2012 T1 (PANSTARRS) has been imaged using the 10.4m Gran
Telescopio Canarias (GTC) and the 4.2m William Herschel Telescope (WHT) at six
epochs in the period from November 2012 to February 2013, with the aim of
monitoring its dust environment. The dust tails brightness and morphology are
best interpreted in terms of a model of sustained dust emission spanning 4 to 6
months. The total dust mass ejected is estimated at 6--25 kg.
We assume a time-independent power-law size distribution function, with
particles in the micrometer to centimeter size range. Based on the quality of
the fits to the isophote fields, an anisotropic emission pattern is favored
against an isotropic one, in which the particle ejection is concentrated toward
high latitudes ( to ) in a high obliquity object
(=80). This seasonally-driven ejection behavior, along with the
modeled particle ejection velocities, are in remarkable agreement to those we
found for P/2010 R2 (La Sagra) \citep{Moreno11a}.Comment: Accepted for publication in The Astrophysical Journal Letter
Sintaxis formal y sintaxis conceptual : más allá de la tipologÃa de las oraciones de relativo
In this paper I present a conceptual analysis of adjectival subordination.
It is argued that adjectival subordination conveys the conceptual operation
of eventive characterization of individuals. This operation consists in using
an event to characterize an individual; it is claimed that many syntactic
properties of adjectival subordination in the world's languages follow
from this conceptual operation, and that a full explanation of the typology
of this type of subordination can only be produced in a semantic
framework. It is also shown how adjectival subordination interacts with
other syntactic processes such as incorporation, verbal adjectivization
and substantivation, elision, anaphora and how these interactions can be
accounted for in the conceptual framework sketched in this paper. The
examples illustrating the main points are drawn from Georgian, Chukchi,
Hungarian, Basque and Spanish, since the investigation is typologically
oriented.En este artÃculo presento un análisis conceptual de la subordinación adjetivada. Se plantea que la subordinación adjetivada transmite la acción conceptual de la eventual caracterización de individuos. Esta operación consiste en usar un evento para definir a una persona; se declara que muchas propiedades sintácticas de la subordinación adjetival en los idiomas del mundo siguen esta acción conceptual, y que una explicación completa de la tipologÃa de este tipo de subordinación sólo puede ser producida en un marco de trabajo semántico. También se muestra cómo la subordinación adjetival interactúa con otros procesos sintácticos como la incorporación, la adjetivación verbal y la sustantivación, la omisión y la anáfora, y el cómo estas interacciones pueden ser recogidas en el espacio de trabajo conceptual que se abarca en este artÃculo. Los ejemplos que ilustran los puntos principales se recogen del georgiano, chukchi, húngaro, vasco y español, ya que la investigación está orientada tipológicamente
The role of sound symbolism in protolanguage: Some linguistic and archaeological speculations
In this paper, I have tried to clarify the role of sound symbolism in the early development of human language vocabulary The mimicking of natural sounds by means of an articulated language, producing onomatopoeic sound-symbolism could be considered as one first stage in human language vocabulary evolution. The following step consists in using sounds to symbolize phenomena perceptible by non-auditory senses. Sound symbolization began to relate certain sounds to the visual aspects of objects such as size or shape or to certain aspects of actions and states. This is called pheno-mimic sound-symbolism. The transition from phono-mimic or onomatopoeic sound symbolism to pheno-mimic sound representations can be related to the stage of human mind evolution proposed by S. Mithen (1996) in which domain-specific modules work together with a seamless flow of information across different domains. This is called cognitive fluidity. This cognitive fluidity could be responsible for the connection between different cognitive abilities: visual processing, auditory processing and the socialsemiotic activity of linguistic symbolism
- …