13,299 research outputs found
Probing the ejecta of evolved massive stars in transition: A VLT/SINFONI K-band survey
Massive evolved stars in transition phases, such as Luminous Blue Variables
(LBVs), B[e] Supergiants (B[e]SGs), and Yellow Hypergiants (YHGs), are not well
understood, and yet crucial steps in determining accurate stellar and galactic
evolution models. The circumstellar environments of these stars reveal their
mass-loss history, identifying clues to both their individual evolutionary
status and the connection between objects of different phases. Here we present
a survey of 25 such evolved massive stars (16 B[e]SGs, 6 LBVs, 2 YHGs, and 1
Peculiar Oe star), observed in the K-band with the Spectrograph for INtegral
Field Observation in the Near-Infrared (SINFONI; R = 4500) on the ESO VLT UT4 8
m telescope. The sample can be split into two categories based on spectral
morphology: one group includes all of the B[e]SGs, the Peculiar Oe star, and
two of the LBVs, while the other includes the YHGs and the rest of the LBVs.
The difference in LBV spectral appearance is due to some objects being in a
quiescent phase and some objects being in an active or outburst phase. CO
emission features are found in 13 of our targets, with first time detections
for MWC 137, LHA 120-S 35, and LHA 115-S 65. From model fits to the CO band
heads, the emitting regions appear to be detached from the stellar surface.
Each star with ^12CO features also shows ^13CO emission, signaling an evolved
nature. Based on the level of ^13C enrichment, we conclude that many of the
B[e]SGs are likely in a pre-Red Supergiant phase of their evolution. There
appears to be a lower luminosity limit of log L/L_solar = 5.0 below which CO is
not detected. The lack of CO features in several high luminosity B[e]SGs and
variability in others suggests that they may in fact be LBV candidates,
strengthening the connection between these two very similar transition phases.Comment: 20 pages, 13 figures, 7 tables. Accepted for publication in A&
Influência das condições climáticas na ocorrência das lesões foliares por Phaeosphaeria maydis.
Observation of an orbital interaction-induced Feshbach resonance in 173-Yb
We report on the experimental observation of a novel inter-orbital Feshbach
resonance in ultracold 173-Yb atoms, which opens the possibility of tuning the
interactions between the 1S0 and 3P0 metastable state, both possessing
vanishing total electronic angular momentum. The resonance is observed at
experimentally accessible magnetic field strengths and occurs universally for
all hyperfine state combinations. We characterize the resonance in the bulk via
inter-orbital cross-thermalization as well as in a three-dimensional lattice
using high-resolution clock-line spectroscopy.Comment: 5 pages, 4 figure
Cultivares, densidades e espaçamentos entre fileiras na cultura do algodoeiro em Mato Grosso do Sul.
Este trabalho teve como objetivo avaliar o comportamento de quatro cultivares de algodoeiro em três locais do Estado de Mato Grosso do Sul, utilizando-se espaçamentos entre fileiras de 0,30; 0,60; 0,90 e 1,20 m, nas densidades de 4, 8, 12 e 16 plantas m-1.bitstream/item/38777/1/BP200523.pd
Granulometria e conteúdos de carbono e nitrogênio do solo sob diferentes fitofisionomias da fazenda Nhumirim, Pantanal Sul-Mato-Grossense.
Análise de solos: finalidade e procedimentos de amostragem.
A análise de solos é o único método que permite, antes do plantio, conhecer a capacidade de um determinado solo suprir nutrientes para as plantas. É a forma mais simples, econômica e eficiente de diagnose da fertilidade das terras e constitui base imprescindível para a recomendação de quantidades adequadas de corretivos e fertilizantes para aumentar a produtividade das culturas e, como consequência a produção e a lucratividade das lavouras.bitstream/CPAP-2010/57309/1/COT79.pd
Produtividade do algodoeiro em rotação com soja no sistema plantio direto.
bitstream/item/65691/1/Cot-34-2001.pd
- …