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Pulsar wind nebulae (PWNe) are main gamma-ray emitters in the Galactic plane. Although the leptonic scenario is able to explain most PWNe emission well, a hadronic contribution cannot be excluded. High-energy emission raises the possibility…

We present a spectroscopic investigation of 25 objects previously reported as possible Planetary Nebulae (PNe) in recent catalogs to obtain their physical properties and to establish their true nature. We found 11 objects showing intense…

We report observations of the high (R$\sim$18000) and medium (R$\sim$5900) resolution, near-infrared spectra of Jupiter's polar regions with the GNIRS instrument at the Gemini North telescope. The observations correspond to the area of main…

We report the first detection of X-ray emission in a pre-planetary nebula, Hen 3-1475. Pre-planetary nebulae are rare objects in the short transition stage between the Asymptotic Giant Branch and planetary nebula evolutionary phases, and…

We have detected CO+ toward the photon-dominated region (PDR) associated with the reflection nebula NGC 7023. This is the first detection of CO+ in the vicinity of a Be star. A CO+ column density of ~ 3E11 cm-2 has been derived toward the…

A hot central star illuminating the surrounding ionized H II region usually produces very rich atomic spectra resulting from basic atomic processes: photoionization, electron-ion recombination, bound-bound radiative transitions, and…

Several Pulsar Wind Nebulae (PWNe) have been detected in the TeV band in the last decade.The TeV emission is typically interpreted in a purely leptonic scenario, but this usually requires that the magnetic field in the Nebula be much lower…

Diffuse X-ray emission has been detected in a small number of planetary nebulae (PNe), indicating the existence of shocked fast stellar winds and providing support for the interacting-stellar-winds formation scenario of PNe. However, the…

We present VLT UVES echelle spectrophotometry of the Orion nebula in the 3100 to 10400 A range. We have measured the intensity of 555 emission lines, many of them corresponding to permitted lines of different heavy-element ions. This is the…

Emission from the molecular ion H$_3^+$ is a powerful diagnostic of the upper atmosphere of Jupiter, Saturn, and Uranus, but it remains undetected at Neptune. In search of this emission, we present near-infrared spectral observations of…

Exoplanets that receive stellar irradiance of approximately Earth's or less have been discovered and many are suitable for spectral characterization. Here we focus on the temperate planets that have massive H2-dominated atmospheres, and…

A significant fraction of the molecular gas in star-forming regions is irradiated by stellar UV photons. In these environments, the electron density (n_e) plays a critical role in the gas dynamics, chemistry, and collisional excitation of…

We present deep optical spectra of the archetypal young planetary nebula (PN) NGC 7027, covering a wavelength range from 3310 to 9160 A. The observations were carried out by uniformly scanning a long slit across the entire nebular surface,…

Accurate emission line fluxes from planetary nebulae (PNe) provide important constraints on the nature of the final phases of stellar evolution. Large, evolved PNe may trace the latest stages of PN evolution, where material from the AGB…

We present far-IR (57-196 mu) spectra of 21 protostars in the Orion molecular clouds, obtained with the Photodetector Array Camera and Spectrometer (PACS) onboard the Herschel Space observatory, as part of the Herschel Orion Protostar…

Neptune-size exoplanets are less studied as characterizing their atmospheres presents challenges due to their relatively small radius and atmospheric scale height. As the most common outcome of planet formation, these planets are crucial…

Spectroscopic observations obtained with the VLT of one planetary nebula (PN) in Sextans A and of five PNe in Sextans B and of several HII regions (HII) in these two dwarf irregular galaxies are presented. The extended spectral coverage,…

This paper continues our study of the behaviour of near infrared helium recombination lines in planetary nebula. We find that the 1.7007um 4^3D-3^3P HeI line is a good measure of the HeI recombination rate, since it varies smoothly with the…

This paper presents an analysis of the concentration of the hydrogen molecule inside the ionized region of planetary nebulae. The equations corresponding to the ionization and chemical equilibria of H, H+, H-, H2, H2+, and H3+ are coupled…

The presence of O VI ions can be indicative of plasma temperatures of a few times 10^5 K that is expected in heat conduction layers between the hot shocked stellar wind gas at several 10^6 K and the cooler (~10,000 K) nebular gas of…