We present Hα, [N II] lambda6583, [O III] lambda5007 ground-based images, Hubble Space Telescope (HST) (V band) archival images, VLA-A 3.6 cm continuum data, and high-resolution long-slit spectra of the planetary nebula NGC 6884. The VLA and HST images show an extremely knotty and filamentary nebula with an elliptical central structure also

We present in this paper a detailed study of the kinematical properties of the ionized gas around the young massive star clusters in the nucleus of NGC 4214. The analysis is based on bidimensional spectroscopical data, allowing to derive the spatial variation of different properties (intensity, velocity and width / line splitting) of the emission

Based on ISO short-wavelength spectrograph (SWS)+long-wavelength spectrograph (LWS) observations, IRAS 16594-4656 is identified as a new member of the rare class of C-rich proto-planetary nebulae with the 21 μm dust feature in emission. In addition, the major polycyclic aromatic hydrocarbon (PAH) emission bands at 3.3, 6.2, 7.7, 8.6, and 11.3 μm

Helioseismology requires continuous measurements of very long duration, months to years. This paper addresses the specific and limited case of full disk measurements of p-mode oscillations, although it can be generalized, to some extent, to the case of imaged helioseismology. First, a method of mode by mode (or rather pair of modes by pair of modes

In this paper we develop an evolutionary stellar population synthesis model to predict spectral energy distributions (SEDs) for single-age, single-metallicity stellar populations (SSPs) at resolution ~1.8 Å in two reduced but very important spectral regions around 4000 and 5000 Å. The input stellar database is composed of a subsample of ~500 stars

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