170 research outputs found

    The TWA 3 Young Triple System: Orbits, Disks, Evolution

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    We have characterized the spectroscopic orbit of the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbit as well as for the wide TWA 3A--B orbit. TWA 3 is a hierarchical triple located at 34 pc in the \sim10 Myr old TW Hya association. The wide component separation is 1."55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbital solution using high-resolution infrared spectroscopy which angularly resolved the A and B components. We then refined the preliminary orbit by combining the infrared data with a re-analysis of our high-resolution optical spectroscopy. The orbital period from the combined spectroscopic solution is \sim35 days, the eccentricity is \sim0.63, and the mass ratio is \sim0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbital solution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planes with respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least \sim30 degrees. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbits and disk.Comment: Accepted to Ap

    Detección de Leucoptera sinuella (Reutti) (Lepidoptera: Lyonetiidae) en Chile, con la identificación de algunos parasitoides asociados

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    En marzo del 2015 el Servicio Agrícola y Ganadero (SAG), a través de actividades de vigilancia forestal, detectó por primera vez en Chile la presencia de Leucoptera sinuella (Reutti), atacando follaje de álamos (Populus spp., Salicaceae), en la comuna de Talagante (Región Metropolitana de Santiago). Actividades de prospección desarrolladas por el SAG han determinado que este microlepidóptero se encuentra distribuido en diversas comunas de las regiones de Valparaíso, Metropolitana de Santiago, Libertador General Bernardo O’Higgins, Maule, Ñuble y Biobío. Adicionalmente, fueron identificadas siete especies de microhimenópteros parasitoides asociados a L. sinuella, pertenecientes a las familias Eulophidae (6 especies) y Chalcididae (1 especie)
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