Related papers: EUV-driven ionospheres and electron transport on e…
The chemical evolution of an exoplanetary Venus-like atmosphere is dependent upon the ultraviolet to near ultraviolet (FUV-NUV) radiation ratio from the parent star, the balance between CO$_{2}$ photolysis and recombination via reactions…
The best-characterized exoplanets to date are planets on close-in transiting orbits around their host stars. The high level of irradiation and transiting geometry of these objects make them ideal targets for atmospheric investigations.…
Radiation in the extreme ultraviolet (EUV) and soft X-ray holds clues to the location of the missing baryons, the energetics in stellar feedback processes, and the cosmic enrichment history. Additionally, EUV and soft X-ray photons help…
The planet-star interaction is manifested in many ways. It was found out that a close-in exoplanet causes small but measurable variability in the cores of a few lines in the spectra of several stars which corresponds to the orbital period…
HD17156b is a newly-found transiting extrasolar giant planet (EGP) that orbits its G-type host star in a highly eccentric orbit (e~0.67) with an orbital semi-major axis of 0.16 AU. Its period, 21.2 Earth days, is the longest among the known…
The detections of atomic hydrogen, heavy atoms and ions surrounding the extrasolar giant planet (EGP) HD209458b constrain the composition, temperature and density profiles in its upper atmosphere. Thus the observations provide guidance for…
The bolometric radiation from a central body is potentially a powerful driver of atmospheric escape from planets or satellites. When heated above their equilibrium temperatures those satellites, due to their low surface gravity, are be…
Context. The detection of the He I 10830 A triplet in exoplanet atmospheres has opened a new window for probing planetary properties, including atmospheric escape. Unlike Lyman alpha, the triplet is less affected by ISM absorption.…
High-energy radiation from the Sun governs the behavior of Earth's upper atmosphere and such radiation from any planet-hosting star can drive the long-term evolution of a planetary atmosphere. However, much of this radiation is unobservable…
The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with older generation stars showing higher $\alpha$-element abundances while the later generations becoming enriched…
Isolated galaxies are the ideal reference sample to study the galaxy structure minimising potential environmental effects. We selected a complete sample of 14 nearby, late-type, highly inclined ($i\geq80^{\circ}$), isolated galaxies from…
A key first step to constrain the impact of energetic particles in exoplanet atmospheres is to detect the chemical signature of ionisation due to stellar energetic particles and Galactic cosmic rays. We focus on GJ$\,$436, a well-studied M…
Aims. We study the evolution of rotation and high energy X-ray, extreme ultraviolet (EUV), and Ly-alpha emission for F, G, K, and M dwarfs, with masses between 0.1 and 1.2 Msun, and provide our evolutionary code and a freely available set…
The formation of gas giant planets must occur during the first few Myr of a star's lifetime, when the protoplanetary disc still contains sufficient gas to be accreted onto the planetary core. The majority of protoplanetary discs are exposed…
Cosmic rays provide an important source for free electrons in the Earth's atmosphere and also in dense interstellar regions where they produce a prevailing background ionization. We utilize a Monte Carlo cosmic ray transport model for…
Stellar population models produce radiation fields that ionize oxygen up to O+2, defining the limit of standard HII region models (<54.9 eV). Yet, some extreme emission line galaxies, or EELGs, have surprisingly strong emission originating…
It is becoming clear that the atmospheres of the young, self-luminous extrasolar giant planets imaged to date are dusty. Planets with dusty atmospheres may exhibit detectable amounts of linear polarization in the near-infrared, as has been…
Spectroscopic studies of extreme-ionization galaxies (EIGs) are critical to our understanding of exotic systems throughout cosmic time. These EIGs exhibit spectral features requiring >54.42 eV photons: the energy needed to fully ionize…
The evolution of a planet's atmosphere depends strongly on its host star's properties. When their host stars are younger, planets can experience stronger winds and EUV emissions. This is particularly true for planets orbiting M-dwarfs due…
Medium-resolution spectra from 3650 angstroms to 10,000 angstroms are presented for 96 giant H II regions distributed in 20 spiral galaxies. We have calculated two separate grids of photoionization models, adopting single-star atmospheres…