As planets grow the exchange of angular momentum with the gaseous component of the protoplanetary disc produces a net torque resulting in a variation of the semi-major axis of the planet. For ...low-mass planets not able to open a gap in the gaseous disc this regime is known as type I migration. Pioneer works studied this mechanism in isothermal discs finding fast inward type I migration rates that were unable to reproduce the observed properties of extrasolar planets. In the last years, several improvements have been made in order to extend the study of type I migration rates to non-isothermal discs. Moreover, it was recently shown that if the planet's luminosity due to solid accretion is taken into account, inward migration could be slowed down and even reversed. In this work, we study the planet formation process incorporating, and comparing, updated type I migration rates for non-isothermal discs and the role of planet's luminosity over such rates. We find that the latter can have important effects on planetary evolution, producing a significant outward migration for the growing planets.
We present observations of the young multiple system UX Tauri to look for circumstellar disks and for signs of dynamical interactions. We obtained SPHERE/IRDIS deep differential polarization images ...in the J and H bands. We also used ALMA archival CO data. Large extended spirals are well detected in scattered light coming out of the disk of UX Tau A. The southern spiral forms a bridge between UX Tau A and C. These spirals, including the bridge connecting the two stars, all have a CO (3-2) counterpart seen by ALMA. The disk of UX Tau C is detected in scattered light. It is much smaller than the disk of UX Tau A and has a major axis along a different position angle, suggesting a misalignment. We performed PHANTOM SPH hydrodynamical models to interpret the data. The scattered light spirals, CO emission spirals and velocity patterns of the rotating disks, and the compactness of the disk of UX Tau C all point to a scenario in which UX Tau A has been perturbed very recently (about 1000 years) by the close passage of UX Tau C.
Tovomita stergiosii, a new species of Clusiaceae from the Venezuelan and Peruvian Amazonian region, is described, illustrated, and compared to its closest relative, T. brasiliensis (Martius) Walpers ...from Brazil, from which it differs in leaf shape, pedicel length, floral parts, and fruit shape.
Swartzia barnebyana, a new legume species with a vining habit from the state of Amazonas in Venezuela, is described and illustrated. The new species belongs to section Possira, series Unifoliolatae, ...in which it is closely related to both S. floribunda Spruce ex Bentham and S. iniridensis R. S. Cowan, by its intramarginally interconnected primary veins and its densely strigulose-velutinous pubescence on branchlets, inflorescence axes, and external calyx segments. Swartzia barnebyana may be distinguished from both related species mainly by the type and color of the ovary pubescence, shape and size of leaflet blades, number of calyx segments, and absence of pubescence in the internal surface of the calyx. /// Se describe e ilustra Swartzia barnebyana, una especie nueva de leguminosa con hábito trepador del estado Amazonas, Venezuela. La especie nueva pertenece a la sección Possira, serie Unifoliolatae dentro de la cual se relaciona estrechamente con S. floribunda Spruce ex Bentham y S. iniridensis R. S. Cowan por las venas primarias interconectadas intramarginalmente y la pubescencia densamente estrigulosa-velutina sobre ramitas, eje de las inflorescencias y segmentos externos del cáliz. Swartzia barnebyana se distingue de las especies relacionadas, principalmente por el tipo y color de la pubescencia en el ovario, la forma y tamaño de la lámina de los folíolos, el número de segmentos del cáliz y la ausencia de pubescencia en la superficie interna del cáliz.
Two new species, Aegiphila aracaensis from Brazil and A. hystricina from Venezuela, are described and illustrated, and their relationships with allied species are discussed. Aegiphila aracaensis ...shares morphological similarities with A. venezuelensis Moldenke, although it differs in leaf shape, length, and width, and in the corolla tube externally covered by a denser canescent indument. Aegiphila hystricina is a shrub to small tree distinguished by its congested elongate inflorescences, and the flowers subtended by three bracteoles covered by glandular trichomes, 8- to 10-septate. The species is related to Aegiphila arcta Moldenke, but differs from it in leaf shape, length, and width, petiolate leaves, and larger glandular trichomes.
A new species of Andira from Estado Bolívar, Venezuela, is described. Andira tervequinata R. T. Pennington, G. Aymard & N. Cuello is clearly distinct from all other Andira species, although it might ...be confused with A. trifoliolata Ducke because specimens often have some trifoliolate leaves.
Rudgea tayloriae (Rubiaceae), a new species from the eastern slopes of the Venezuelan Andes, is described and illustrated, and its relationships are discussed.
Two new large-leaved species of Tovomita are described: T. auriculata from Venezuelan and Peruvian Amazon lowland forests, and T. foldatsii from Venezuelan Amazon lowland forests. The morphological ...relationships to related species are discussed. /// Se describen dos especies nuevas de Tovomita: T. auriculata de los bosques de tierras bajas de la Amazonía de Perú y Venezuela y T. foldatsii de los bosques de tierras bajas de la Amazonía venezolana. Se discuten sus relaciones morfológicas con especies afines.
Two new species of Sterigmapetalum subg. Sterigmapetalum are described from Venezuela and Brazil: S. chrysophyllum and S. plumbeum. Relationships with related species are discussed, and an ...illustration for each species is provided. /// Se describen dos nuevas especies de Sterigmapetalum subgénero Sterigmapetalum de Venezuela y Brasil: S. chrysophyllum y S. plumbeum. Se discuten sus relaciones con las especies afines y se presentan ilustraciones de cada una de ellas.
Desmodium adscendens (Swartz) DC. var. orinocense DC. se ha elevado a nivel de especie como D. orinocense (DC.) Cuello, y se le ha designado un lectótipo. /// Desmodium adscendens (Swartz) DC. var. ...orinocense DC. is elevated to species level as Desmodium orinocense (DC.) Cuello, and a lectotype is designated.
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