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Aca entontrara algunas secciones de interes

Sebastian Bruzzone
Research and Theaching Assitant at The University of Western Ontario.
jbruzzon(at)uwo.ca
Physics and Astronomy Building Room 134
Meteor Lab phone: +5196612111 ext 87985

Trabajos Publicados en Congresos y en Revistas Referadas

Aqui encontrara algunos trabajos de investigacion, como publicaciones referadas y presentaciones en congresos internacionales como en congresos nacionales. Estos trabajos incluyen los trabajos en las campañas de observación de estrellas por TNOs, el estudio de asteroide (5088) Tancredi, como dos posters presentados en la asamblea XXVII de la IAU en Rio, y una presentacion oral en Asteroids Comets Meteors, en Baltimore, USA. El area de investigacion corresponde a los cuerpos menores del Sistema Solar, area principal de investigacion del Departamento de Astronomia.  Los archivos pueden ser descargados o vistos en forma embebida desde este sitio usando flexpaper.

    Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation.
    J L Ortiz, B Sicardy, F Braga-Ribas, A Alvarez-Candal, E Lellouch, R Duffard, N Pinilla-Alonso
    , V D Ivanov, S P Littlefair, J I B Camargo, [......]
    Nature 11/2012; 491(7425):566-9.
    Abstract: Pluto and Eris are icy dwarf planets with nearly identical sizes,
    comparable densities and similar surface compositions as revealed by spectroscopic studies.
    Pluto possesses an atmosphere whereas Eris does not; the difference probably
    arises from their differing distances from the Sun, and explains their different albedos. Makemake is
    another icy dwarf planet with a spectrum similar to Eris and Pluto, and is currently at a distance to
    the Sun intermediate between the two. Although Makemake's size (1,420 +/- 60 km) and albedo are roughly known, there has been no constraint on its density and there were expectations that it could have a Pluto-like
    atmosphere. Here we report the results from a stellar occultation by Makemake on 2011 April 23.
    Our preferred solution that fits the occultation chords corresponds to a body with projected
    axes of 1,430 +/- 9 km (1sigma) and 1,502 +/- 45 km, implying a V-band geometric albedo p(V) = 0.77 +/- 0.03. This albedo is larger than that of Pluto, but smaller than that of Eris. The disappearances and reappearances of the
    star were abrupt, showing that Makemake has no global Pluto-like atmosphere at an upper limit of 4-12
    nanobar (1sigma) for the surface pressure, although a localized atmosphere is possible. A density of 1.7 +/- 0.3g/cm(3) is inferred from the data.

  • Size, shape, albedo, density and atmospheric limit of transneptunian object (50000) Quaoar
    from multi-chord stellar occultations (submitted)
    F. Braga-Ribas, B. Sicardy, J.L. Ortiz, E. Lellouch, G. Tancredi [..]
    Abstract: We present results derived from the first multi-chord stellar occultations by
    the transneptunian object (50000) Quaoar, observed on 4 May 2011 and 17 Febru- ary 2012, and from a single-chord occultation observed on 15 October 2012. If the timing of the five chords obtained in 2011 is correct, then Quaoar possesses topographic features (crater or mountain) that are too
    large for a body of this mass. An alternative model consists in applying time shifts
    to some chords, to ac- count for possible timing errors. Satisfactory elliptical fits
    to the chords are then possible, yielding an equivalent radius Requiv = 555+/-2.5 km
    and geometric visual albedo pV = 0.109 +/- 0.007. Assuming that Quaoar is a Maclaurin
    spheroid with indeterminate polar aspect angle, we derive a true oblateness of = 0.087+0.0268-0.0175
    an equatorial radius of 569+24-17 km and a density of 1.99 +/- 0.46 g/cm(3) . The orientation of our preferred solution in the plane of the sky implies that Quaoar's satellite Weywot cannot have an equatorial
    orbit. Finally, we do not detect any global atmosphere around Quaoar, with an upper limit
    of 21 nbar for a pure methane atmosphere.

  • Stellar Occultations by TNOs: the January 08 2011 by 2003 AZ84 and the May 04 2011 by (50000) Quaoar. European Planetary Science Congress. Nuestro grupo ha observado cinco ocultaciones de estrellas por TNOs donde fue posible obtener tanto tamaño como la forma para algunos de los objetos, Varuna, Eris, 2003 AZ84, Makemake y Quaoar. En este resumen presentamos los resultados para dos de estos objetos, la ocultación estelar por 2003 AZ84 y la ocultación del 4 de Mayo por Quaoar.
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  • 5088 TANCREDI: ROTATION PERIOD AND PHASE COEFFICIENTS . Tancredi et al. (2011). Minor Planet Bulletin. The main-belt asteroid 5088 Tancredi was observed during a period of 42 days close to the 2009 opposition. The data were collected with a clear filter on 15 different nights. R-magnitudes were calculated using the MPOSC3 Catalog. The observations covered a range of phase angles from 0.35° to 16°. The phase coefficients in the H-G system (R-mag) are: HR = 12.36 HR = 12.36 [12.30, 12.43]; G = 0.058 [–0.036, 0.153], with 95% confidence range presented within the brackets. Based on the low value of G, the asteroid can be tentatively classified as a C-type asteroid. A precise estimate of the rotation period is computed as P = 5.05909 ± 0.00014 h. The amplitude is A = 0.31 mag.
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  • Search of Low Activity of Asteroids in Cometary Orbits (ACOs) Utilizando un criterio dinamico proporcionado por G. Tancredi, sobre la poblacion de asteroides en la base de datos de AstDys, seleccionamos una muestra de estos objetos, que bajo este criterio podrian ser catalogados como Asteroides en Orbitas Cometarias, o ACOs. Un turno de observacion fue asignado para el seguimiento de estos candidatos y asi realizar mediciones de sus psf sobre exposiciones lo suficientemente largas, del orden de una hora, en busqueda de indicios de actividad cometaria de cualquier naturaleza.(INGLES)
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  • Lightcurves of Icy Dwarf Planets Presentamos los resultados de curvas de luz de 11 TNOs con datos de tres turnos de observacion en CASELO y CTIO. Las curvas de luz ayudaran a la clasificacion de estos planetas enanos helados como posibles plutoides. 9 fueron los cuerpos seleccionados de una lista de 39 candidatos donde se obtuvo datos de los siguientes objetos:(120178) 2003OP32, (145453) 2005RR43, (145452) 2005RN43, (145451) 2005RM43, (47171) 1999TC36, (55637) 2002UX25, (145452) 2005RN43, (120178) 2003OP32, 2002MS4, 2007UK126 and (55565) 2002AW197. (S. Roland as main contributor)(INGLES)
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  • ITOKAWA: A Global Shacken and Fractured Asteroid with Brazilian Nut Effect.(Abstract) Las imagenes de la sonda espacial Hayabusa mostraban una interesante, y plausible, correlacion entre la distribucion de rocas en la superficie del asteroide Itokawa y su potencial gravitacional. Se sugirio por parte de G. Tancredi, hacer un estudio de la distribucion cumulativa de rocas y realizar el computo del potencial gravitacional sobre la superficie de este asteroide. Utilizando un modelo facetado de la mision Hayabusa, y un codigo implementado en Matlab junto con las herramientas provistas por SPICE, se logro calcular y establecer un potencial para este objeto irregular y su distribucion cumulativa de rocas. Esto llevo a la conclusion de que este asteroide de tipo 'pila de escombros' debe su forma al efecto 'nueces de Brasil'.(INGLES)
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”Perhaps the most widespread evil is the Western view of man and nature.
Among us, it is widely believed that man is apart from nature, superior to it;
indeed, evolution is a process to create man and seat him on the apex of the
cosmic pinnacle. He views the earth as a treasury that he can plunder at will.
And, indeed, the behavior of Western people, notably since the advent of the
Industrial Revolution, gives incontrovertible evidence to support this assertion.”
Ian McHarg, 1971

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