The atmospheric parameters were derived using a strictly spectroscopic method based on the LTE analysis of equivalent widths of FeI and FeII lines. With existing photometric data and the Hipparcos parallaxes, we estimated stellar masses and ages via evolutionary tracks fitting. The stellar radii were calculated from either estimated masses and the

Cosmological simulations make use of sub-grid recipes for the implementation of galactic winds driven by massive stars because direct injection of supernova energy in thermal form leads to strong radiative losses, rendering the feedback inefficient. We argue that the main cause of the catastrophic cooling is a mismatch between the mass of the gas

We analyze the spectral asymmetry of Stokes V (circularly polarized) profiles of an individual network patch in the quiet Sun observed by Sunrise/IMaX. At a spatial resolution of 0farcs15-0farcs18, the network elements contain substructure which is revealed by the spatial distribution of Stokes V asymmetries. The area asymmetry between the red and

We report the detection of orbital decay in the 12.75-minute, detached binary white dwarf (WD) SDSS J065133.338+284423.37 (hereafter J0651). Our photometric observations over a 13 month baseline constrain the orbital period to 765.206543(55) s and indicate that the orbit is decreasing at a rate of (- 9.8 ± 2.8) × 10-12 s s-1 (or -0.31 ± 0.09 ms yr

We have performed power spectral analysis of surface temperatures, velocities, and magnetic fields, using spectropolarimetric data taken with the Hinode Solar Optical Telescope. When we make power spectra in a field of view covering the supergranular scale, kinetic and thermal power spectra have a prominent peak at the granular scale while the

Esta tesis doctoral se centra en la búqueda y caracterización de enanas marrones (cuerpos celestes con ~13-75 veces la masa de Júpiter, MJup) y objetos aislados de masa planetaria (con masas por debajo del límite de combustión del deuterio a ~13MJup) en las regiones de formación estelar Sigma Orionis (~3 Ma) y Upper Scorpio (~5 Ma). En el cúmulo