We present preliminary analyses of Stokes [I, Q, U, V] spectra of a sunspot penumbra using two different analysis/inversion procedures. It has long been known that the Stokes spectra from sunspot penumbrae, even at disk center, commonly show multiple lobes and asymmetries. Hence, the magnetic/thermodynamic maps obtained from Stokes spectra using

The spatial distribution of stellar populations, the star formation history, and other properties of the dwarf irregular (dIrr) galaxy DDO 190 have been analyzed using color-magnitude diagrams of about 3900 resolved stars and the Hα fluxes of H II regions. From the mean color index of the red giant branch (RGB), a mean metallicity [Fe/H]=-2.0 is

Analyses of the near-ultraviolet continuum of late-type stars have led to controversial results regarding the performance of state-of-the-art model atmospheres. The release of the homogeneous International Ultraviolet Explorer (IUE) final archive and the availability of the high-accuracy Hipparcos parallaxes provide an opportunity to revisit this

A long flux enhancement, with an exponential decay time of 86 min, is detected in 4U 1735-44 with the BeppoSAX Wide Field Cameras. We argue that this is a type I X-ray burst, making it the longest such burst ever observed. Current theories for thermonuclear bursts predict shorter and more frequent bursts for the observed persistent accretion rate.

Multiple shell planetary nebulae (MSPNe) are those which, in addition to the main bright inner shell, show one or two additional external shells. These faint external shells often have aspherical geometries, indicating an interaction with the surrounding interstellar medium (ISM). Our aim is to investigate, first of all, if the current theoretical

The High Altitude Observatory of the National Center for Atmospheric Research (HAO/NCAR) in collaboration with the Instituto de Astrofísica de Canarias (IAC) have recently completed a two-station helioseismic network with sites at Mauna Loa, Hawaii and Izana, Tenerife. The instruments are Doppler imagers employing Magneto-Optical filters and are