An Updated Small Magellanic Cloud and Magellanic Bridge Catalog of Star Clusters, Associations, and Related Objects

We present a catalog of star clusters, associations, and related extended objects in the Small Magellanic Cloud (SMC) and the Magellanic Bridge with 2741 entries, a factor 2 more than a previous version from a decade ago. Literature data up until 2018 December are included. The identification of star clusters was carried out with digital atlases in various bands currently available in the Digitized Sky Survey and the Machine Automatique à Mésurer pour l'Astronomie. imaging surveys. In particular, we cross-identified recent cluster samples from the Visible and Infrared Survey Telescope for Astronomy near-infrared YJK s survey of the Magellanic System, Optical Gravitational Lensing Experiment IV, and Survey of the MAgellanic Stellar History surveys, confirming new clusters and pointing out equivalencies. A major contribution of the present catalog consists of the accurate central positions for clusters and small associations, including a new sample of 45 clusters or candidates in the SMC and 19 in the Magellanic Bridge, as well as a compilation of the most reliable age and metallicity values from the literature. A general catalog must also deal with the recent discoveries of 27 faint and ultra-faint star clusters and galaxies projected on the far surroundings of the Clouds, most of them from the Dark Energy Survey. The information on these objects has been complemented with photometric, spectroscopic, and kinematical follow-up data from the literature. The underluminous galaxies around the Magellanic System, still very few as compared to the predictions from Λ Cold Dark Matter simulations, can bring constraints to galaxy formation and hierarchical evolution. Furthermore, we provide diagnostics, when possible, of the nature of the ultra-faint clusters, searching for borders of the Magellanic System extensions into the Milky Way gravitational potential. © 2020. The American Astronomical Society. All rights reserved..Indexación: Scopu

Triterpenos pentacíclicos e esteróides da casca do uchi (Sacoglottis uchi, Humiriaceae)

The ethanol extract from stem bark of Sacoglottis uchi Huber (popularly known as \x93uchi\x94 in the Amazon Region) was submitted to chromatographic fractionation. The dichloromethane fractions provided the pentacyclic triterpene 3-oxo-friedelin (1). The dichloromethane:methanol fractions provided the pentacyclic triterpenes pseudotaraxasterol (2), lupeol (3), a-amyrin (4), betulin (5), and methyl 2ß,3ß-dihydroxy-urs-12-en-28-oate (6) and a mixture of the steroids sitosterol (7) and stigmasterol (8). Their chemical structures were determined by NMR spectroscopy and comparison with spectroscopic data from the literature. All compounds are described for the first time in this species.O extrato etanólico da casca do caule de Sacoglottis uchi Huber (conhecida popularmente como \x93uchi\x94 na Amazônia) foi submetido a fracionamento cromatográfico. As frações eluídas com diclorometano forneceram o triterpeno pentacíclico 3-oxo-friedelina (1). As frações em diclorometano:metanol forneceram os triterpenos pentacíclicos pseudotaraxasterol (2), lupeol (3), a-amirina (4), betulina (5) e 2ß,3ß-di-hidroxi-urs-12-en-28-oato de metila (6), além de uma mistura dos esteróides sitosterol (7) e estigmasterol (8). Suas estruturas químicas foram determinadas por espectroscopia de RMN e comparação com os dados espectroscópicos descritos na literatura. Todas as substâncias isoladas são descritas pela primeira vez nesta espécie