Chromospheric CaII Emission in Nearby F, G, K, and M stars

We present chromospheric CaII activity measurements, rotation periods and ages for ~1200 F-, G-, K-, and M- type main-sequence stars from ~18,000 archival spectra taken at Keck and Lick Observatories as a part of the California and Carnegie Planet Search Project. We have calibrated our chromospheric S values against the Mount Wilson chromospheric activity data. From these measurements we have calculated median activity levels and derived R'HK, stellar ages, and rotation periods for 1228 stars, ~1000 of which have no previously published S values. We also present precise time series of activity measurements for these stars.Comment: 62 pages, 7 figures, 1 table. Second (extremely long) table is available at http://astro.berkeley.edu/~jtwright/CaIIdata/tab1.tex Accepted by ApJ

The Evolution of Blue Stragglers Formed Via Stellar Collisions

We have used the results of recent smoothed particle hydrodynamic simulations of colliding stars to create models appropriate for input into a stellar evolution code. In evolving these models, we find that little or no surface convection occurs, precluding angular momentum loss via a magnetically-driven stellar wind as a viable mechanism for slowing rapidly rotating blue stragglers which have been formed by collisions. Angular momentum transfer to either a circumstellar disk (possibly collisional ejecta) or a nearby companion are plausible mechanisms for explaining the observed low rotation velocities of blue stragglers. Under the assumption that the blue stragglers seen in NGC 6397 and 47 Tuc have been created solely by collisions, we find that the majority of these blue stragglers cannot have been highly mixed by convection or meridional circulation currents at anytime during their evolution. Also, on the basis of the agreement between the predictions of our non-rotating models and the observed blue straggler distribution, the evolution of blue stragglers is apparently not dominated by the effects of rotation.Comment: 36 pages, including 1 table and 7 postscript figures (LaTeX2e). Also avaliable at http://astrowww.phys.uvic.ca/~ouellet/ . Accepted for publication in A

Ten Low Mass Companions from the Keck Precision Velocity Survey

Ten new low mass companions have emerged from the Keck precision Doppler velocity survey, with minimum (msini) masses ranging from 0.8 mjup to 0.34 msun. Five of these are planet candidates with msini < 12 mjup, two are brown dwarf candidates with msini ~30 mjup, and three are low mass stellar companions. Hipparcos astrometry reveals the orbital inclinations and masses for three of the (more massive) companions, and it provides upper limits to the masses for the rest. A new class of extrasolar planet is emerging, characterized by nearly circular orbits and orbital radii greater than 1 AU. The planet HD 4208b appears to be a member of this new class. The mass distribution of extrasolar planets continues to exhibit a rapid rise from 10 mjup toward the lowest detectable masses near 1 msat.Comment: 26 pages, TeX, plus 13 postscript figure

Fluctuations of the number of participants and binary collisions in AA interactions at fixed centrality in the Glauber approach

In the framework of the classical Glauber approach, the analytical expressions for the variance of the number of wounded nucleons and binary collisions in AA interactions at a given centrality are presented. Along with the optical approximation term, they contain additional contact terms arising only in the case of nucleus-nucleus collisions. The magnitude of the additional contributions, e.g., for PbPb collisions at SPS energies, is larger than the contribution of the optical approximation at some values of the impact parameter. The sum of the additional contributions is in good agreement with the results of independent Monte Carlo simulations of this process. Due to these additional terms, the variance of the total number of participants for peripheral PbPb collisions and the variance of the number of collisions at all values of the impact parameter exceed several multiples of the Poisson variances. The correlator between the numbers of participants in colliding nuclei at fixed centrality is also analytically calculated.Comment: updated version; as published by Phys. Rev.

Planetary Companions Around Two Solar Type Stars: HD 195019 and HD 217107

We have enlarged the sample of stars in the planet search at Lick Observatory. Doppler measurements of 82 new stars observed at Lick Observatory, with additional velocities from Keck Observatory, have revealed two new planet candidates. The G3V/IV star, HD 195019, exhibits Keplerian velocity variations with a period of 18.27 d, an orbital eccentricity of 0.03 +/- 0.03, and M sin i = 3.51 M_Jup. Based on a measurement of Ca II H&K emission, this star is chromospherically inactive. We estimate the metallicity of HD 195019 to be approximately solar from ubvy photometry. The second planet candidate was detected around HD 217107, a G7V star. This star exhibits a 7.12 d Keplerian period with eccentricity 0.14 +/- 0.05 and M sin i = 1.27 M_Jup. HD 217107 is also chromospherically inactive. The photometric metallicity is found to be [Fe/H] = +0.29 +/- 0.1 dex. Given the relatively short orbital period, the absence of tidal spin-up of HD 217107 provides a theoretical constraint on the upper limit of the companion mass of < 11 M_Jup.Comment: 15 pages, plus 6 figures. To appear in Jan 1999 PAS

Desempenho de milho inoculado com Azospirillum brasiliense associado a doses de nitrogênio em cobertura.

RESUMO: Uma das alternativas de redução no consumo de fertilizantes nitrogenados na cultura do milho é a inoculação de sementes com bactérias diazotróficas que possuem a capacidade de fixar N atmosférico no solo. O objetivo deste trabalho foi avaliar algumas características agronômicas e o rendimento de grãos de milho cultivado em Latossolo Vermelho com diferentes doses de N em cobertura, na presença e ausência de inoculação de sementes com Azospirillum brasilense. Os experimentos foram conduzidos em Papanduva e em Campos Novos, SC, nos anos agrícolas 2011/12 e 2012/13, utilizando-se delineamento fatorial 2 x 6, com os tratamentos alocados em blocos casualizados, com três repetições, avaliando-se a variedade de milho de polinização aberta SCS155 Catarina. Os fatores testados foram a inoculação com A. brasilense (presença e ausência) e doses de N em cobertura (0, 25, 50, 75, 100 e 125kg ha-1). A inoculação de sementes de milho com A. brasilense não aumenta o rendimento de grãos e não altera a massa de mil grãos, estatura de plantas, altura da inserção da espiga principal e diâmetro do colmo. A aplicação de N em cobertura no milho influencia de modo positivo o rendimento de grãos. ABSTRACT: One of the alternatives to reduce the consumption of nitrogen fertilizers in corn production is seed inoculation with diazotrophic bacteria that have the ability of fixing atmospheric N in the root zone. The aim of this study was to evaluate some agronomic characteristics and grain yield of maize grown in an Oxisol with the presence and absence of seed´s inoculation with Azospirillum brasilense associated with different nitrogen doses (0, 25, 50, 75, 100 and 125kg/ha). The experiments were carried out in the municipalities of Papanduva and Campos Novos, in Santa Catarina State (Southern Brazil), during the 2011/12 and 2012/13 seasons. The experiments were ploted in a 2x6 factorial with the treatments assigned in a randomized blocks with three replications, using the corn cultivar ?SCS155 Catarina? as indicator. The inoculation of seeds with Azospirillum brasilense does not increase the corn yield and does not alter the weight of the grains, plant height, ear height and main stem diameter. Nitrogen application in corn influences positively the grain yield

Produtividade de milho inoculado com Azospirillum brasilense em diferentes doses de nitrogênio, em latossolo vermelho - safra 2012/13.

O objetivo desse trabalho foi avaliar a produtividade do milho cultivado em Latossolo Vermelho na safra 2012/13, na presença ou ausência de inoculação de sementes com A. brasilense, em diferentes doses de N em cobertura. A inoculação de sementes de milho com Azospirillum brasilense não proporcionou incrementos significativos na produtividade de grãos de milho cultivados na safra 2012/13, em Latossolo Vermelho de Campos Novos e de Papanduva. Em Papanduva, as doses de N aplicadas em cobertura aumentaram a produtividade de grãos de milho

Two New Candidate Planets in Eccentric Orbits

Doppler measurements of two G-type main-sequence stars, HD210277 and HD168443, reveal Keplerian variations that imply the presence of companions with masses (M sin i) of 1.28 and 5.04 M_Jup and orbital periods of 437 d and 58 d, respectively. The orbits have large eccentricities of e=0.45 and e=0.54, respectively. All 9 known extrasolar planet candidates with a=0.2-2.5 AU have orbital eccentricities greater than 0.1, higher than that of Jupiter (e=0.05). Eccentric orbits may result from gravitational perturbations imposed by other orbiting planets or stars, by passing stars in the dense star-forming cluster, or by the protoplanetary disk. Based on published studies and our near-IR adaptive optics images, HD210277 appears to be a single star. However, HD168443 exhibits a long-term velocity trend consistent with a close stellar companion, as yet undetected directly.Comment: AASTeX, 31 pages including 10 Postscript figures, to appear in the Astrophysical Journal (July 1999

Produtividade de milho inoculado com Azospirillum brasilense em diferentes doses de nitrogênio, em latossolo vermelho - safra 2011/12.

O objetivo desse trabalho foi avaliar a produtividade do milho cultivado em Latossolo Vermelho na safra 2011/12, na presença ou ausência de inoculação de sementes com Azospirillum brasilense, em diferentes doses de N em cobertura. A inoculação de sementes de milho com Azospirillum brasilense e a aplicação de doses de nitrogênio em cobertura não proporcionaram incrementos significativos na produtividade de grãos de milho cultivados na safra 2011/12, em Latossolo Vermelho de Campos Novos e Canoinhas

Produtividade de genótipos de milho na presença ou ausência de inoculação com Azospirillum brasilense e adubação nitrogenada de cobertura - Safra 2012/13.

O objetivo desse trabalho foi avaliar a produtividade de genótipos de milho com bases genéticas distintas, na presença ou ausência de inoculação de sementes com A. brasilense e de adubação nitrogenadas de cobertura. A inoculação de sementes de milho com Azospirillum brasilense não proporcionou incrementos significativos na produtividade de grãos de milho, em diferentes genótipos, com e sem adubação nitrogenada de cobertura. A adubação com 100 kg ha-1 de N, aplicados em cobertura, proporcionou aumento de produtividade de grãos de milho em relação à ausência de adubação nitrogenada de cobertura. Nos dois locais avaliados, houve variação entre genótipos para produtividade de grãos, todavia sem interação com adubação nitrogenada de cobertura e inoculação com Azospirillum brasilense