Buscar
Mostrando ítems 41-50 de 56
Planet Detectability in the Alpha Centauri System
(Institute of Physics Publishing, 2018)
We use more than a decade of radial-velocity measurements for α Cen A, B, and Proxima Centauri from the High Accuracy Radial Velocity Planet Searcher, CTIO High Resolution Spectrograph, and the Ultraviolet and Visual Echelle ...
Model-independent large-scale magnetohydrodynamic quantities in magnetic clouds
(Elsevier, 2005-12)
Magnetic clouds are the interplanetary manifestation of coronal mass ejections, which are transient expulsions of major quantities of magnetized plasma, from the Sun toward the heliosphere. The magnetic flux and helicity ...
The test case of HD 26965: difficulties disentangling weak doppler signals from stellar activity
(IOP Publishing Ltd, 2018)
We report the discovery of a radial velocity signal that can be interpreted as a planetary-mass candidate orbiting the K dwarf HD 26965, with an orbital period of 42.364 +/- 0.015 days, or alternatively, as the presence ...
Linking two consecutive non-merging magnetic clouds with their solar sources
(American Geophysical Union, 2009-12)
On 15 May 2005, a huge interplanetary coronal mass ejection (ICME) was observed near Earth. It triggered one of the most intense geomagnetic storms of solar cycle 23 (Dstpeak = −263 nT). This structure has been associated ...
Discovery of an activity cycle in the solar-analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates
(EDP Sciences, 2016-05)
Context. Most stellar activity cycles similar to that found in the Sun have been detected by using the chromospheric Ca ii H&K lines as stellar activity proxies. However, it is unclear whether such activity cycles can be ...
Rotação diferencial em estrelas do tipo solar
(Universidade Federal do Rio Grande do NorteBRUFRNPrograma de Pós-Graduação em FísicaFísica da Matéria Condensada; Astrofísica e Cosmologia; Física da Ionosfera, 2014-04-07)
Stellar differential rotation is an important key to understand hydromagnetic
stellar dynamos, instabilities, and transport processes in stellar interiors as well as for
a better treatment of tides in close binary and ...
Prediction of the occurrence of flares in the solar cycle 24 from the evolution of magnetic polarity barycenters in active regions
(Universidad Nacional de ColombiaBogotá - Ciencias - Maestría en Ciencias - AstronomíaObservatorio Astronómico NacionalFacultad de CienciasBogotá, ColombiaUniversidad Nacional de Colombia - Sede Bogotá, 2021)
Solar bipolar active regions and the processes that occur in them have been studied and analyzed for decades, generating many types of models and characterizations for the occurrence of different eruptive events that take ...
Análise astrométrica e espectroscópica de estrelas do aglomerado jovem NGC 6530
(Universidade Federal de Minas GeraisBrasilICX - DEPARTAMENTO DE FÍSICAPrograma de Pós-Graduação em FísicaUFMG, 2020-03-13)
In this work, we have studied NGC 6530, a young (∼ 2.3 Myr) open cluster located at a distance of 1325 pc from the Sun. The study of young clusters provides crucial information about the star formation process, because ...
The effect of ISM absorption on stellar activity measurements and its relevance for exoplanet studies
(EDP Sciences, 2017-05)
Past ultraviolet and optical observations of stars hosting close-in Jupiter-mass planets have shown that some of these stars present an anomalously low chromospheric activity, significantly below the basal level. For the ...
On the generation of subphotospheric acoustic sources
(Universidad Nacional de ColombiaBogotá - Ciencias - Maestría en Ciencias - AstronomíaObservatorio Astronómico NacionalFacultad de CienciasBogotá, ColombiaUniversidad Nacional de Colombia - Sede Bogotá, 2021)
This work explored the possibility of the generation of seismic signals on the Sun from a confinement of energy located in the solar interior. This idea was developed through two sections. In the first section, corresponding ...